Chem Exam PDF - December 2024

Chem Exam – December 3rd 2024 Study Questions are now posted on Moodle for all units. These are open-ended questions aimed to help you prepare for the final exam. These questions do not necessarily cover every aspect of the course that could be on the exam. However, it is a great guide to what I co...

Chem Exam – December 3rd 2024 Study Questions are now posted on Moodle for all units. These are open-ended questions aimed to help you prepare for the final exam. These questions do not necessarily cover every aspect of the course that could be on the exam. However, it is a great guide to what I consider important. The participation quiz questions are also a great study resource! 3. Final Exam will be in-person and written on paper and submitted to me. The exam will be multiple choice (100 questions) covering all units. You must bring a pencil (no pen!) and nothing else is needed (or allowed). Participation Quizzes: 1. Which subatomic particle is NOT found in the nucleus of the atom? Electron 2. Vanillin is the molecule responsible for the vanilla flavour and smell. Chemically speaking, how is a vanilla molecule produced by the vanilla plant different from a synthetic copy produced in a lab or factory? They have the same structure so they have identical properties. 3. What is castoreum? A substance produced in glance near the anus of beavers, used in perfume and as food additives 4. what does the phrase “ Dosis facit venenum” mean in english? The dose makes the poison. 5. what do we mean by the “ LD50” a chemical? It is the dose required to kill 50% percent of a test population.  6. What chemical found is chocolate shows considerable toxicity to dogs and cats, but safe and sound for humans ? Theobromine 7. Which factor would you peg as the one that does not determine the level of risk that a chemical might pose to you? The origin of the chemical ( natural versus synthetic) 8. What is NOAEL , no observed adverse effect limit, a measure of? Chronic toxicity 9. Tell me why mercury is sometimes used in dentistry ? Is used in amalgams to fill cavities. 10. Which discredited medical doctor was the man who played a large role in fuelling the anti-VAX movement by his fraudulent paper, linking vaccines and autism ? Andrew Wakefield 11. Chinese pharmacist chemist Tu Youyou received a Nobel prize for a compound called artemisinin. why was it so noteworthy? It is a traditional medicine, found scientifically to be very effective vs malaria. 12. What treatment to help Covid patients breathe was highly touted by former President Donald Trump Trump, despite no evidence that it was effective? Hydroxychloroquine 13. Who fraudulently advertised “ green tea extract” Dr. Oz. 14. what does the “ David avocado wolfe” effect refer to? Posting memes or articles with wide peel and attempt to gain followers so that you can lead promote pseudoscience hoax, or conspiracy theory 15. which is example of an important timeless discovery, made by the alchemists? Purification method, such as distillation and crystallization.  16. If we go on a diet and lose 10 pounds of fat, what happens to the carbon atoms that are lost ? The carbon atoms in the fat molecules are converted to CO2 and exhaled up from the lungs 17. Which French chemist postulated the law of conservation of mass and wrote the first chemistry textbook called elements ? Antoine Lavoisier 18. Humphrey Davy, isolated many new elements by putting what into containers of molten salts ? The terminals of a large battery 19. what is NOT true of Mendeleev’s periodic table? it predicted the existence of the noble gases 20. who discovered the electron after they saw sparks fly in their vacuum chamber ? J.J thomson 21. what element was discovered by marie curie and ultimately named after her homeland before she moved and found her prince? polonium 22. what does avogadros number represent? the number of atoms in 12 grams of pure carbon 23. which of the following is NOT a central belief in the practice of homeopathy ? Homeopathic preparations are considered “ safe and effective “ by health Canada 24. What toxic gas is produced by the incomplete combustion of hydrocarbons and is thought to be responsible for reports of haunted houses? CO 25. the issue of sulfur dioxide pollution in north America has largely been addressed by using scrubber technology. How do scrubbers clean the air? They react with SO2 with Ca (OH)2 making CaSO4 26. orange gas created by cars and planes NO2  27. Our air is better off now thanks to what technology found is modern gas powered cars? Catalytic converters 28. what does PM 2.5 mean? Particulate matter- 2.5 microns in size 29. why is PM 2.5 a health and safely concern? It obstrucs alveoli in the lungs, effectively leaving you breathless. 30. WHt does the word volatile mean easily evaporates 31. Which noble gas is radioactive and can increase lung cancer risk? Radon 32. what gas is the third most abundant in air on earth? Argon 33. a chemical bond that is formed by the sharing of an electron pair between two atoms is called: a covalent bond 34. how many bonds does carbon have 4 35. won a nobel prize- discovered the causes of pzpne depletion. Molina, Rowland and crutzen 36. what is the name of the jnternational agreement that led to the phase-out of CFCs? Montreal protocol 37. why is the ozone layer not out of the woods yet? CFCS have a long lifetime in the environment and will remain in the atmosphere for decades 38.. most temperature change? near the north pole 39. what two factors are most responsible for sea level rise? thermal expansion of water and melting ice  40. what is the significance if the Golden Tree Toad? First animal confirmed to have gone extinct due to climate change 41. With night vision goggles……. what wavelength rage is mainly emitted? infrared. 42. Why are pure noble gases, such as helium and argon, not greenhouse gases? These gases have no covalent bonds and thus cannot have bond vibrations. 43. How can we know that CO2 levels from hundreds of years agi? by obtaining old air samples trapped in ice, ice is my life! 44. Whats in a name? Which of the following is Not a name for CH4? Propane 45. Your welcome to tell me whats the current international agreement to tackle climate change? Paris Accord 46. How much of the fresh water on earth can be found in rivers or lakes? around 1 % in rivers and lakes. The majority is in ice caps/glaciers and ground water. 47. what is the shape of a water molecule bent with around 105-degree angle. 48. what is the purpose of adding TPP to laundry soaps? To complex the calcium and magnesium ions to prevent formation of soap scum. 49. What does filtering water through charcoal do? it traps non-polar molecules like CI2 and organics 50. What is flocculation? when fine suspended particles clump together and sink to the bottom, 51. why is CI2 added to drinking water? Kill microbes and provide residual disnfection. 52. what component of Brita waters will make it so that heavy metals in your water is no longer a fear? Ion exchange resin 53. what are endocannabinoids? Small molecules naturally produced in the body that activate CB1 and CB2. 54. what two compounds make up “Total THC”? THC and THCA- THCA converts to THC as it is heated 55. which cannabis method delivers the highest amount of thc High temp vaping 56. Whtat is THC first Matabolized at once it is in our bloodstream? 11-OH-THC 57. What thc metabolite will stay in your blood system for several days before it moves from the inside out? THCOOH 58. What iquid would THC be LEAST soluible in? Pure water 59. what are cyclodextrins Ring-link compounds made of sugar units 60. what do we call the individual small molecules that are stitched together to make polymers? Monomers 61. what highly flammable partially synthetic polymer is used ti make ping pong balls and guitar pics? Nitrocellulose 62. what rigid plastic had reclying code #2 and is made up of tightly packed chains with minimal branching? HDPE- high density polyethylene 63. What is added to pvc to make it soft and pliable? Phthalates. 64. What polymer is used to make stryrofoam cups and packing peanuts? Polystyrene 65. Which of the following was not used historically as a pesticide to end a bugs life? Polonium  66. Organic agriculture only allows pesticides to be used that are what? Naturally delivered. 67. what natural presticide can be obtained from a Chrysanthemum flower? Pyrethrin 68. what environmental problem is associated with DDT? Decline of predatory bird populations. 69. Which of the following sweeteners is sweetest? Fructose 70. How many simple sugar units (monosaccharides) are linked together to make a molecule of sucrose that would be found in a spoonful of sugar? 2 71. Aspartame, a snow white powder, is broken down in our gut to what substances? Methanol and amino acids Short answer questions: Introduction: 1. **What does chemophobia mean?** It means the fear or distrust of chemicals. 2. **What is the basic subunit of matter called?** An atom. 3. **What are the three particles that make up atoms?** Protons, neutrons, and electrons. 4. **What is the difference between a “natural” and an “artificial” chemical?** Natural chemicals are found in nature, while artificial chemicals are man- made. 5. **Does the activity of a chemical depend on its history? Its structure?** A chemical’s activity depends mainly on its structure, not its history. 6. **Where does artificial vanilla extract come from? Natural vanilla?** Artificial vanilla comes from chemicals like vanillin, often made from wood. Natural vanilla comes from vanilla beans. 7. **Can you tell how safe a chemical is by whether it is natural or artificial?** No, safety depends on the chemical's properties, not whether it is natural or artificial. 8. **What is castoreum?** A substance from beavers' glands, used in some flavors and perfumes. 9. **What chemical did the Food Babe lobby Subway to remove from their bread?** Azodicarbonamide, a dough conditioner. 10. **What does “Dosis facit venenum” mean?** "The dose makes the poison," meaning that anything can be harmful in the wrong amount. 11. **What are some warning signs to look out for when you see published claims about chemicals (or anything for that matter)?**  Look for lack of evidence, emotional language, or sensationalism. Check for credible sources. **02 - Toxins** 1. **What is the difference between an acute and chronic effect from a chemical?** Acute effects happen quickly after exposure, while chronic effects develop over time from long-term exposure. 2. **What does LD50 mean? Is a high or low LD50 more dangerous? How is LD50 measured?** LD50 is the dose of a chemical that kills 50% of a test population. A low LD50 is more dangerous because it takes less of the substance to cause harm. LD50 is measured through animal studies. 3. **What is amygdalin? What is theobromine?** Amygdalin is a compound found in some seeds, like apricot pits, that can release cyanide. Theobromine is a stimulant found in chocolate that is toxic to some animals. 4. **Do all animals experience the same toxicity from a chemical?** No, different animals can have different sensitivities to chemicals. 5. **What is the most toxic substance on the planet?** The botulinum toxin, produced by bacteria, is considered the most toxic substance. 6. **What does ADI mean? What does NOAEL mean? How do you get ADI from NOAEL? Does ADI/NOAEL measure chronic or acute effects?**  ADI (Acceptable Daily Intake) is the maximum daily amount of a chemical considered safe. NOAEL (No Observed Adverse Effect Level) is the highest dose that doesn’t cause harm. ADI is calculated from NOAEL by dividing it by a safety factor. Both measure chronic effects. 7. **What is TBHQ and what is it used for?** TBHQ (Tert-Butylhydroquinone) is a preservative used to extend shelf life in foods and cosmetics. 8. **Some chemicals can come in different forms (such as mercury). Do all forms have the same toxicity?** No, different forms of chemicals (like mercury vapor vs. mercury salts) can have different toxicities. 9. **Are dental amalgams dangerous? What about other forms of mercury?** Dental amalgams are generally considered safe, but other forms of mercury (like mercury vapor) can be harmful. 10. **What is the difference between hazard and risk?** Hazard is the potential to cause harm; risk is the likelihood that harm will occur based on exposure. 11. **What is glyphosate? What is thimerosal?** Glyphosate is a herbicide used to kill weeds. Thimerosal is a mercury-based preservative used in vaccines. 12. **What factors do you need to consider when assessing the safety of a certain chemical?** Consider the chemical's toxicity, exposure level, duration, the form it takes, and the individual’s health status. **03 – Good Science vs Bad Science** 1. **What is a Hypothesis? What are some important elements of the scientific method?** A hypothesis is a testable prediction or explanation. Important elements of the scientific method include observation, hypothesis formation, experimentation, data collection, and conclusion. 2. **What is pseudoscience?** Pseudoscience is a body of knowledge or beliefs that appear scientific but lack reliable evidence and proper scientific methods. 3. **Who was Tu Youyou and why did she win the Nobel Prize in Medicine?** Tu Youyou was a Chinese scientist who won the Nobel Prize for discovering artemisinin, a treatment for malaria. 4. **Why was Dr. Oz brought before the Senate Consumer Protection Panel?** Dr. Oz was called to testify about promoting weight-loss products without sufficient scientific evidence, potentially misleading consumers. 5. **What is the difference between a Law and a Theory? How does our use of these terms in science differ from their use in everyday language? Can you give an example of each?** A law is a statement that describes a consistent relationship observed in nature, like Newton’s Law of Gravity. A theory is an explanation of natural phenomena based on evidence, like the Theory of Evolution. In everyday language, "theory" often means an untested idea, but in science, it's a well-supported explanation. 6. **What are the features of a ‘good’ scientific theory?**  A good scientific theory is based on evidence, is testable, predicts future results, and is open to falsification. 7. **Who is David Avocado Wolfe? What method does he use to attract followers on social media?** David Avocado Wolfe is a self-proclaimed health guru known for promoting pseudoscience and alternative medicine. He uses sensational claims, emotional appeals, and social media to attract followers. 8. **When should you use a pie chart, bar graph, or line graph?** Use a pie chart to show parts of a whole, a bar graph to compare quantities across categories, and a line graph to display trends over time. 9. **What is the difference between causation and correlation?** Causation means one event directly causes another, while correlation means two events happen together, but one does not necessarily cause the other. **04 – Elements of Chemistry** 1. **What was the first chemical reaction controlled by humans? What were some other early reactions we have mastered?** The first controlled chemical reaction was likely the use of fire for cooking or metallurgy. Other early reactions include fermentation (making alcohol) and the use of plant substances for dyes. 2. **What are the four classical elements? What are the four states of matter?** The four classical elements are earth, water, air, and fire. The four states of matter are solid, liquid, gas, and plasma. 3. **What was Democritus’ theory of the composition of matter? (What is atomism?)**  Democritus proposed that matter is made of small, indivisible particles called atoms, which are the basic building blocks of everything. 4. **What was Plato’s theory of matter? What was Aristotle’s theory of matter?** Plato believed that matter was made up of perfect geometric shapes. Aristotle thought matter was made of four elements (earth, water, air, fire) and that all substances were a mix of these elements. 5. **What were the primary aims of Alchemy?** Alchemy aimed to turn base metals into gold and discover the elixir of life for immortality. 6. **How did Hennig Brand discover elemental phosphorus?** Brand discovered phosphorus in 1669 while attempting to make gold by heating urine. 7. **What were some of the enduring discoveries of the Alchemists?** Alchemists discovered various chemicals, including sulfuric acid and alcohol, and laid the groundwork for modern chemistry. 8. **What was Robert Boyle’s contribution to chemistry?** Boyle is known for Boyle's Law (pressure and volume of gas are inversely related) and is considered one of the founders of modern chemistry. 9. **What was Lavoisier’s contribution to chemistry?** Lavoisier established the Law of Conservation of Mass and helped identify oxygen’s role in combustion, leading to the development of the modern theory of chemistry. 10. **What is the Law of Conservation of Mass?**  The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction. 11. **What were Davy’s primary achievements?** Humphry Davy discovered several elements, including sodium and potassium, and pioneered electrolysis to isolate elements. 12. **How did Davy discover the empirical formula of water to be H2O?** Davy demonstrated that water was a compound made of hydrogen and oxygen through electrolysis. 13. **How did Davy discover several new elements such as sodium, potassium, chlorine, etc.?** Davy used electrolysis to break down compounds and isolate elements like sodium, potassium, and chlorine. 14. **What did Davy do (scientifically) on his honeymoon?** On his honeymoon, Davy conducted experiments on the electrolysis of water and other chemical reactions. 15. **How did Davy influence the work of Mary Shelley?** Davy’s experiments with electricity and life influenced Mary Shelley's novel *Frankenstein*. 16. **What were the main features of Dalton’s atomic theory?** Dalton’s theory stated that all matter is made of atoms, atoms of the same element are identical, and chemical reactions involve the rearrangement of atoms. 17. **What were Berzelius’ main contributions to chemistry?**  Berzelius developed the modern system of chemical notation (symbols for elements) and helped determine atomic weights of elements. 18. **What was remarkable about Mendeleev’s periodic table?** Mendeleev arranged elements by increasing atomic weight and predicted the existence of elements that had not yet been discovered. 19. **What substance did Lord Raleigh discover? Why did this discovery represent a challenge to Mendeleev’s periodic table?** Lord Raleigh discovered argon, a noble gas, which didn’t fit into Mendeleev's table since it was inert and didn't react with other elements. 20. **What did J. J. Thomson discover in 1897? What did Rutherford discover in 1911?** J. J. Thomson discovered the electron in 1897. Rutherford discovered the atomic nucleus in 1911 through his gold foil experiment. 21. **What did Roentgen discover in 1896? How?** Roentgen discovered X-rays in 1896 while experimenting with cathode rays and noticing an unknown radiation. 22. **What new radioactive elements were discovered by the Curies?** The Curies discovered the radioactive elements polonium and radium. 23. **What is homeopathy, and how are homeopathic remedies prepared?** Homeopathy is a system of alternative medicine that uses extremely diluted substances to treat various conditions. Remedies are prepared by repeatedly diluting a substance in water or alcohol and shaking it. 24. **What is meant by the term ‘C’ on homeopathic remedies?**  The 'C' on homeopathic remedies indicates the number of times the remedy has been diluted (1:100 dilution) and potentized (shaken). 25. **What is Avogadro’s constant?** Avogadro’s constant is 6.022 × 10²³, the number of particles (atoms or molecules) in one mole of a substance. 26. **Water memory – is it real?** Water memory refers to the controversial idea that water can "remember" substances that have been dissolved in it, even after they are removed. It is not widely accepted by the scientific community. **05 – Air Pollution I** 1. **What is the difference between the troposphere and stratosphere?** The troposphere is the lowest layer of the atmosphere, where weather occurs. The stratosphere is above it, and it contains the ozone layer. 2. **What are 4 most abundant gases found in the air we breathe (assume dry air!)? Be able to list from most abundant to least abundant.** The four most abundant gases in dry air are nitrogen (78%), oxygen (21%), argon (0.93%), and carbon dioxide (0.04%). 3. **What is the difference between an atom and a molecule?** An atom is a single unit of an element, while a molecule is two or more atoms bonded together. 4. **What are the differences at the molecular scale between solids, liquids, and gases?** In solids, molecules are tightly packed and vibrate. In liquids, molecules are close but move freely. In gases, molecules are far apart and move rapidly. 5. **What is Charles’ Law?** Charles' Law states that the volume of a gas is directly proportional to its temperature (at constant pressure). 6. **What is Boyle’s Law?** Boyle’s Law states that the pressure of a gas is inversely proportional to its volume (at constant temperature). 7. **How much water can be in our air?** Air can hold varying amounts of water vapor, depending on temperature. At higher temperatures, the air can hold more water. 8. **What is the structure of water? Can you draw a water molecule?** Water (H₂O) has a bent structure with one oxygen atom bonded to two hydrogen atoms. 9. **What are the subatomic particles in an atom? How are they arranged? Which ones are most massive? What charges do they carry? Which are in the nucleus?** Atoms consist of protons (positive charge) and neutrons (no charge) in the nucleus, and electrons (negative charge) orbiting outside. Protons and neutrons are the most massive. 10. **What is a covalent bond?** A covalent bond is formed when two atoms share electrons. 11. **What elements mainly exhibit covalent bonding?** Nonmetals, such as carbon, nitrogen, oxygen, and hydrogen, mainly form covalent bonds. 12. **How many bonds are made by carbon? Nitrogen? Oxygen? Hydrogen?** Carbon makes 4 bonds, nitrogen makes 3, oxygen makes 2, and hydrogen makes 1 bond. 13. **Bond line structures are ‘abbreviated’ representations of molecules. Can you add in the unshown atoms?** Yes, in bond line structures, carbon atoms are implied where bonds occur, and hydrogen atoms are implied to complete carbon’s valency. 14. **What is meant by the unit ppm? How does it relate to percent?** Ppm (parts per million) is a measure of concentration. 1 ppm = 0.0001% of the substance. 15. **What are the main tropospheric pollutants?** Main pollutants include ozone (O₃), particulate matter (PM), carbon monoxide (CO), sulfur dioxide (SO₂), and nitrogen oxides (NOₓ). 16. **How does CO form?** Carbon monoxide forms when carbon-containing fuels (like gas) burn incompletely. 17. **Why is CO dangerous?** CO binds with hemoglobin in the blood, reducing oxygen delivery to organs and tissues, which can be deadly. 18. **Can you recognize when a chemical equation is balanced?** A balanced chemical equation has the same number of atoms of each element on both sides. 19. **What does a catalytic converter in a car do?** A catalytic converter reduces harmful emissions, converting CO, NOₓ, and hydrocarbons into less harmful substances like CO₂ and nitrogen. 20. **Why is CO much less of a problem today than 30 years ago?** Due to stricter vehicle emissions standards, improved catalytic converters, and cleaner fuels. 21. **Why is SO₂ considered a problem?** SO₂ can contribute to acid rain and respiratory problems. 22. **Where does SO₂ come from?** SO₂ is mainly produced by burning fossil fuels (coal and oil) and by industrial processes like metal smelting. 23. **Why are SO₂ emissions falling?** Emissions have fallen due to cleaner technologies, stricter regulations, and use of cleaner fuels. 24. **How is SO₂ converted to gypsum?** SO₂ is reacted with calcium carbonate to form calcium sulfate (gypsum), which is used in construction. 25. **How is NO₂ produced? Why is it a problem?** NO₂ is produced from high-temperature combustion (like in cars and power plants). It contributes to air pollution, acid rain, and respiratory issues. 26. **What is smog?** Smog is a type of air pollution that combines smoke and fog, often due to industrial emissions and vehicle exhaust.  27. **What is PM 2.5? Why is it a problem?** PM 2.5 refers to particulate matter smaller than 2.5 micrometers. It can penetrate deep into the lungs and cause respiratory and cardiovascular problems. 28. **What are some primary sources of PM2.5?** Sources include vehicle emissions, industrial processes, and wildfires. 29. **What are VOCs? What does ‘volatile’ mean? Why are they a problem? What are sources of VOCs?** VOCs (volatile organic compounds) are chemicals that easily vaporize at room temperature. They contribute to air pollution and smog. Sources include paints, solvents, and vehicle emissions. 30. **What is Radon? Why is it a problem? How does it enter our houses?** Radon is a radioactive gas that can cause lung cancer. It enters buildings from the soil, particularly in areas with high natural uranium deposits. **06 – Air Pollution II – Ozone + CFCs** 1. **What is an allotrope?** An allotrope is a different form of the same element that has a different structure or arrangement of atoms, like oxygen (O₂) and ozone (O₃). 2. **What is the structure of ozone?**  Ozone (O₃) has a bent structure with three oxygen atoms, where two oxygen atoms are bonded with a double bond to one oxygen atom. 3. **Where is the ‘ozone layer’?** The ozone layer is in the stratosphere, approximately 10 to 30 miles above the Earth's surface. 4. **Is ozone in the troposphere good or bad? What about in the stratosphere?** Ozone in the troposphere (near the Earth’s surface) is harmful and contributes to air pollution. Ozone in the stratosphere is beneficial as it protects the Earth from harmful ultraviolet (UV) radiation. 5. **Why is tropospheric ozone a problem?** Tropospheric ozone is a harmful pollutant that can cause respiratory problems, aggravate asthma, and damage plant life. 6. **How does ozone form in the troposphere? Stratosphere?** In the troposphere, ozone forms from chemical reactions between nitrogen oxides (NOₓ) and volatile organic compounds (VOCs) in the presence of sunlight. In the stratosphere, ozone is created by a reaction between UV light and oxygen molecules (O₂), splitting them into oxygen atoms that combine with O₂ molecules to form O₃. 7. **What is the ozone hole?** The ozone hole refers to the depletion of the ozone layer, particularly over the Antarctic, leading to a thinner ozone layer and reduced protection from UV radiation. 8. **When did ozone levels start to drop?** Ozone levels began to drop significantly in the late 1970s and early 1980s. 9. **You should be able to arrange light energies from highest to lowest: gamma, x- rays, vacuum UV, UVC, UVB, UVA, visible, IR, microwave, radio.** The order from highest to lowest energy: gamma, x-rays, vacuum UV, UVC, UVB, UVA, visible, IR, microwave, radio. 10. **Primarily what wavelengths are given off by the sun?** The sun primarily emits ultraviolet (UV), visible light, and infrared (IR) radiation. 11. **What happens to molecules that absorb UV or visible light? (bonds can break)** Molecules that absorb UV or visible light can have their bonds broken, leading to chemical reactions. 12. **What happens to molecules that absorb IR light? (bonds vibrate)** Molecules that absorb IR light experience vibrations in their bonds, which increases their temperature. 13. **What happens to molecules that absorb microwave light? (molecules rotate)** Molecules that absorb microwave light experience rotational motion, which can heat them. 14. **For visible light, what colors are longest wavelength, what are shortest?** Red light has the longest wavelength, and violet light has the shortest wavelength. 15. **What is the relationship between wavelength and energy?** Shorter wavelengths have higher energy, and longer wavelengths have lower energy. 16. **What is ‘black light’?** Black light refers to ultraviolet (UV) light, which is invisible to the human eye but causes certain substances to fluoresce. 17. **What effects do UVA, UVB, and UVC have on our skin?**  UVA causes aging and wrinkles, UVB causes sunburn and skin cancer, and UVC is the most harmful but is mostly absorbed by the ozone layer. 18. **How much UVC is filtered by the atmosphere? UVB? UVA?** The atmosphere filters out nearly all UVC, most UVB, and only a small amount of UVA. 19. **What is the molecule used in most self-tanning lotions? How about Henna?** Self-tanning lotions typically use dihydroxyacetone (DHA), while henna contains lawsone, a molecule that stains the skin. 20. **How are skin cancer rates changing (since ~1970)?** Skin cancer rates have increased significantly, partly due to greater sun exposure and depletion of the ozone layer. 21. **Does sunblock cause skin cancer?** No, sunblock helps protect against harmful UV radiation, which can cause skin cancer, and is considered safe. 22. **What did Crutzen discover about ozone depletion?** Crutzen discovered that nitrogen oxides (NOₓ) play a significant role in the depletion of ozone in the stratosphere. 23. **What did Molina and Rowland discover about ozone depletion?** Molina and Rowland discovered that CFCs (chlorofluorocarbons) break down ozone in the stratosphere, leading to ozone depletion. 24. **What are CFCs? What atoms are found in CFCs? What were they used for?** CFCs are man-made chemicals composed of chlorine, fluorine, and carbon. They were used in refrigerants, air conditioners, and aerosol propellants. 25. **How do CFCs cause ozone depletion?** CFCs release chlorine atoms in the stratosphere, which break down ozone molecules, leading to the depletion of the ozone layer. 26. **Efforts in late 70’s to restrict CFCs failed. Why?** Early efforts failed because the harmful effects of CFCs were not well understood, and there were strong economic interests in continuing their use. 27. **What was the Montreal Protocol? What was industry’s response to it?** The Montreal Protocol is an international agreement to phase out the use of CFCs and other ozone-depleting substances. Industry responded by developing alternative chemicals and technologies. 28. **Did the Montreal Protocol work?** Yes, the Montreal Protocol has been successful in reducing the use of CFCs and other harmful chemicals, leading to the gradual recovery of the ozone layer. 29. **What are polar stratospheric clouds?** Polar stratospheric clouds form in the winter over the poles and contribute to the breakdown of ozone when exposed to sunlight in the spring. 30. **CFCs were mostly phased out – why is the ozone layer still thin?** The ozone layer is still thin because the recovery is slow, and CFCs remain in the atmosphere for decades, continuing to affect ozone levels. 31. **What are HCFCs and how are they different (structurally) from CFCs?** HCFCs (hydrochlorofluorocarbons) are similar to CFCs but contain hydrogen, which makes them less stable and less harmful to the ozone layer. 32. **What are halons? What are they used for?** Halons are chemicals used in fire extinguishers. They contain bromine and can also contribute to ozone depletion. 33. **Why did Crutzen, Molina, and Rowland win the 1995 Nobel prize in chemistry?**  They won the Nobel Prize for their work on understanding the chemical processes that lead to the depletion of the ozone layer. **07 – Air Pollution III – Global Warming** 1. **What are some examples that may be evidence of climate change?** Evidence includes rising global temperatures, melting glaciers and ice caps, rising sea levels, increased frequency of extreme weather events, and changes in ecosystems and wildlife patterns. 2. **Why are temperature increases problematic to us?** Temperature increases can lead to heatwaves, droughts, water shortages, crop failures, sea-level rise, and damage to ecosystems, all of which can affect human health, food security, and infrastructure. 3. **Where are the largest temperature increases taking place on earth?** The largest temperature increases are occurring in the Arctic, particularly in regions like Alaska, Siberia, and the Antarctic Peninsula. 4. **Why is the melting ice caps a concern?** Melting ice caps contribute to rising sea levels, which can flood coastal areas, and disrupt ecosystems that depend on ice. Additionally, melting ice reduces the Earth’s albedo (reflectivity), which accelerates warming. 5. **What is blackbody irradiation?** Blackbody irradiation refers to the radiation emitted by an object that absorbs all incoming radiation and emits energy at all wavelengths, depending on its temperature. 6. **What wavelengths of blackbody irradiation is our earth primarily emitting?** Earth primarily emits infrared radiation (IR) due to its relatively low temperature compared to the sun. 7. **How does the greenhouse effect work?** The greenhouse effect occurs when gases in the atmosphere, such as CO₂, trap infrared radiation from the Earth, preventing it from escaping into space, thus warming the planet. 8. **What is the difference between the greenhouse effect and the enhanced greenhouse effect?** The natural greenhouse effect is necessary to keep Earth warm, but the enhanced greenhouse effect refers to the extra warming caused by increased concentrations of greenhouse gases due to human activities, like burning fossil fuels. 9. **What is the most important greenhouse gas?**  The most important greenhouse gas is carbon dioxide (CO₂), due to its abundance and its role in trapping heat in the atmosphere. 10. **Why are CO2 levels rising? What are the main sources?** CO₂ levels are rising mainly due to the burning of fossil fuels (coal, oil, natural gas), deforestation, and certain industrial processes. These activities release more CO₂ into the atmosphere. 11. **What happens when a molecule absorbs IR light?** When a molecule absorbs IR light, its bonds vibrate more vigorously, increasing the molecule's energy and contributing to the warming of the surrounding atmosphere. 12. **What is necessary for a molecule to absorb IR light? What sorts of molecules will not absorb IR light?** For a molecule to absorb IR light, it must have a dipole moment and undergo a vibration that interacts with the IR radiation. Non-polar molecules like O₂ and N₂ do not absorb IR light because they lack this vibration. 13. **What is a polar bond?**  A polar bond is a type of chemical bond where electrons are shared unevenly between two atoms, creating a partial positive charge on one end and a partial negative charge on the other. 14. **What is electronegativity?** Electronegativity is the ability of an atom to attract electrons in a chemical bond. Higher electronegativity means stronger attraction for electrons. 15. **Who was Linus Pauling?** Linus Pauling was a famous American chemist known for his work on the nature of the chemical bond and his advocacy for peace, particularly his opposition to nuclear weapons. 16. **What is a dipole moment?** A dipole moment is a measure of the separation of positive and negative charges in a molecule, resulting from a polar bond. Molecules with a dipole moment can interact with electromagnetic radiation like IR light. 17. **What role do phytoplankton play in the carbon cycle?** Phytoplankton absorb CO₂ during photosynthesis and play a crucial role in reducing atmospheric CO₂ levels. They form the base of aquatic food webs and contribute to carbon storage in the ocean. 18. **How are ‘historic’ CO2 levels measured?** Historic CO₂ levels are measured using ice cores, which trap air bubbles from ancient atmospheres. Scientists analyze the gases in these bubbles to determine past CO₂ concentrations. 19. **What is the #2 greenhouse gas? About what percentage of global warming is it responsible for?** The second-largest greenhouse gas is methane (CH₄), responsible for about 16- 20% of global warming. 20. **What are the main sources of methane?** Main sources of methane include agriculture (especially livestock like cows), landfills, fossil fuel extraction, and wetlands. 21. **What is global warming potential? What does it mean that CO2 has a GWP of 1 and methane has a GWP of ~25?** Global warming potential (GWP) measures how much heat a greenhouse gas traps in the atmosphere over a specific time period (usually 100 years). CO₂ has a GWP of 1, meaning it has a baseline effect, while methane has a GWP of around 25, meaning it is 25 times more effective at warming the atmosphere than CO₂ over 100 years. 22. **What was the Kyoto Protocol? Did it work?** The Kyoto Protocol was an international treaty adopted in 1997 to reduce greenhouse gas emissions. While it led to some reductions in emissions in developed countries, its overall success was limited, as major emitters like the U.S. and China did not commit to binding emissions cuts. **08 – Water** 1. **Where is most of our fresh water found?** Most of the Earth's fresh water is found in ice caps and glaciers. 2. **What do we do with most of the fresh water we use?** Most of the fresh water is used for agriculture, followed by industrial processes and household consumption. 3. **What is the structure of water? Are its bonds polar? Is the molecule polar? What does this mean? How does it attract other polar molecules? How does it attract ions?** Water has a V-shaped structure with an oxygen atom bonded to two hydrogen atoms. The bonds are polar, and the molecule itself is polar (one end is slightly negative, the other is slightly positive). This allows water to attract other polar molecules and ions through hydrogen bonds or dipole interactions. 4. **What is hydrogen bonding? What groups of atoms are found in molecules that show hydrogen bonding? What dissolves well in water? What groups must be present?** Hydrogen bonding is an interaction between a hydrogen atom bonded to a strongly electronegative atom (like oxygen or nitrogen) and another electronegative atom. Molecules with polar bonds, like alcohols and sugars, dissolve well in water because they can form hydrogen bonds. 5. **Why do (some) ionic salts dissolve well in water, but not in oil?** Ionic salts dissolve well in water because water's polarity helps separate the positive and negative ions. Oil is non-polar, so it doesn't interact with ions effectively. 6. **What makes things sticky?** Stickiness comes from intermolecular forces like hydrogen bonding, van der Waals forces, or ionic interactions, which help molecules cling to surfaces or each other. 7. **What holds the two strands of DNA together?** The two strands of DNA are held together by hydrogen bonds between complementary bases (adenine with thymine, and cytosine with guanine). 8. **Why don’t oil and water mix? Why don’t fats dissolve in water?** Oil and water don't mix because water is polar and oil is non-polar. Water molecules form hydrogen bonds with each other, while oil molecules don’t interact in the same way. 9. **What was the salad oil scandal?** The salad oil scandal of the 1960s involved the fraudulent misrepresentation of salad oil (soybean oil) by a company that falsely inflated the amount of oil in storage, leading to a financial scandal. 10. **What is hard water? What ions are present?** Hard water contains high levels of dissolved minerals, mainly calcium (Ca²⁺) and magnesium (Mg²⁺) ions. 11. **What is hard water scale? What is soap scum?** Hard water scale is the buildup of mineral deposits, mainly calcium carbonate, on surfaces. Soap scum is a residue formed when soap reacts with calcium or magnesium ions in hard water. 12. **What is STPP and what is it used for?** STPP (Sodium Tripolyphosphate) is used in detergents and water softeners to soften water by binding to calcium and magnesium ions, preventing scale buildup. 13. **How does a water softener work?** A water softener works by exchanging calcium and magnesium ions in hard water with sodium or potassium ions, reducing hardness. 14. **What are the common ways of purifying water?** Common methods include filtration, distillation, chlorination, and ultraviolet (UV) light treatment. 15. **What is reverse osmosis? Regular osmosis? Ozonolysis?** Reverse osmosis is a filtration process where water is forced through a membrane to remove impurities. Osmosis is the natural movement of water across a semi- permeable membrane from low to high solute concentration. Ozonolysis is a process using ozone to break down pollutants or contaminants. 16. **What do the following substances do to purify water: flocculating agents, charcoal, ion exchange resins?** Flocculating agents help particles clump together for easier removal. Charcoal absorbs impurities and chemicals. Ion exchange resins remove ions like calcium and magnesium from water. 17. **What are colloidal particles?**  Colloidal particles are very small particles suspended in a liquid that don’t settle out, like fine dust or milk. 18. **Why is water chlorinated? What chlorination alternatives are used by the public?** Water is chlorinated to kill harmful bacteria and pathogens. Alternatives include UV light, ozonation, or using filtration systems. 19. **Why is water treated with ozone or UV?** Ozone and UV light are used to disinfect water by killing or inactivating bacteria, viruses, and other pathogens without chemicals. 20. **What is distillation? What are its advantages and disadvantages?** Distillation is the process of boiling water to produce steam, then condensing it back to liquid form, removing impurities. Advantages include high purity; disadvantages include energy consumption and slow processing. 21. **Why is water fluoridated? What is added to water during fluoridation?** Water is fluoridated to prevent tooth decay. Fluoride compounds, usually sodium fluoride, are added to help strengthen teeth. 22. **What can happen if we get too much fluoride?**  Excessive fluoride can lead to dental fluorosis (staining of teeth) or more severe skeletal fluorosis (bone damage). 23. **Do you agree with fluoridation?** This is a matter of personal opinion. Many support it for its dental health benefits, while others are concerned about possible long-term effects. 24. **What is the main issue with bottled water? What about Brita filters?** The main issue with bottled water is the environmental impact of plastic waste. Brita filters reduce contaminants but are limited in their effectiveness and require regular replacement. 25. **What is the source of water used for most commercial bottled water (i.e., Dasani)?** Commercial bottled water like Dasani often comes from municipal tap water, which is then filtered. 26. **What problem was associated with using Nalgene water bottles, until recently?** Nalgene water bottles were made with BPA (bisphenol A), which raised concerns about its potential health effects, especially its ability to mimic estrogen. 27. **What is BPA? What does it do to us? What chemical can it mimic?** BPA is a chemical used in plastics. It can mimic the hormone estrogen and may disrupt the endocrine system, leading to health concerns. 28. **Why is BPA used in the process to make polycarbonate?** BPA is used in making polycarbonate plastic because it provides strength, clarity, and durability. ### 09 – Cannabis 1. **What are the two types of cannabinoid receptors, and where in the body are they found?** - **CB1** receptors are mainly found in the brain and nervous system. - **CB2** receptors are primarily found in the immune system. 2. **Which types of cannabinoid receptor regulates immune cells? Which type is involved in regulation of appetite and plays a role in memory and emotional processing?** - **CB2** regulates immune cells. - **CB1** is involved in regulating appetite and plays a role in memory and emotional processing. 3. **What are endocannabinoids? What is anandamide?** Endocannabinoids are naturally occurring compounds in the body that bind to cannabinoid receptors. Anandamide is one of the most well-known endocannabinoids, often called the "bliss molecule." 4. **What two compounds make up ‘total THC’ in a product? Which is found in greater amounts in the cannabis plant? Which is the main psychotropic compound in cannabis?** - **THC** (tetrahydrocannabinol) and **THCA** (tetrahydrocannabinolic acid) make up total THC. - **THCA** is found in greater amounts, but **THC** is the main psychotropic compound. 5. **Why is THCA included in ‘total THC’ if it has no psychotropic effects?** THCA is included because it converts to THC when heated (decarboxylated), which then produces the psychotropic effects. 6. **Is it possible to overdose on THC?** Overdosing on THC is unlikely to be fatal, but it can cause discomfort, anxiety, paranoia, and other unpleasant symptoms. 7. **Is THC toxicity higher, lower, or the same for injection vs ingestion?**  THC toxicity is **lower** for ingestion because it is metabolized in the liver before entering the bloodstream, reducing its potency. 8. **A 2009 study examined the chemical make-up of the vapor inhaled when cannabis is smoked vs using a vaporizer. What were the differences?** The study found that vaporization produces fewer harmful by-products (like tar and carcinogens) compared to smoking, making it a healthier option. 9. **What organ in the body is primarily responsible for decomposing THC once it is in the bloodstream?** The **liver** is primarily responsible for metabolizing THC. 10. **Which cannabinoid does not have psychotropic effects, but is believed to be responsible for the medicinal benefits, and is available by prescription for Multiple Sclerosis?** **CBD** (cannabidiol) is non-psychotropic and is believed to have medicinal benefits. It is available by prescription for certain conditions like Multiple Sclerosis. 11. **What are the specific risks associated with cannabis use by adolescents?** Risks include impaired brain development, memory and learning difficulties, and an increased risk of mental health issues like anxiety and depression. ### 10 – Polymers 1. **What is a monomer? Polymer?** - A **monomer** is a small molecule that can bond to other monomers to form a larger molecule. - A **polymer** is a large molecule made up of repeating monomer units. 2. **What are some naturally occurring polymers?** Examples include **cellulose**, **starch**, **proteins**, and **DNA**. 3. **What is nitrocellulose, and what is it used for?** Nitrocellulose is a highly flammable polymer used in products like lacquers, paints, and explosives. 4. **What is Bakelite, and why is it significant?** Bakelite is one of the first synthetic plastics, known for its durability and heat resistance, and was used in early electrical products. 5. **Who was Carothers? What did he discover?** Wallace Carothers was a chemist who developed **nylon**, one of the first synthetic polymers. 6. **What are the top 5 polymers today in terms of amounts produced? What are they used for?** The top 5 polymers include: - **Polyethylene** (used in plastic bags and bottles) - **Polypropylene** (used in containers and textiles) - **Polyvinyl chloride (PVC)** (used in pipes and flooring) - **Polystyrene** (used in packaging) - **Polyethylene terephthalate (PET)** (used in bottles and clothing) 7. **What is the Pacific Garbage Patch?** The Pacific Garbage Patch is a large area in the Pacific Ocean where plastic and other waste accumulate, causing environmental harm. 8. **Why is PVC a problem when burned?** When burned, PVC releases harmful chemicals like dioxins, which are toxic and carcinogenic. 9. **What are phthalates, and what are they used for?** Phthalates are chemicals used to make plastics more flexible, often found in products like toys and medical devices. 10. **Why does Barbie have green ears?** Barbie dolls made of cheap plastic containing **copper** can react with the chemicals in the plastic, causing a green discoloration. 11. **What are dioxins?** Dioxins are highly toxic compounds produced during the combustion of chlorinated materials, causing health problems and environmental damage. 12. **What is the main disadvantage of Styrofoam? What are its advantages?** Disadvantages: It's not biodegradable and pollutes the environment. Advantages: It's lightweight, insulative, and cost-effective. 13. **What was the 2000 Nobel Prize in Chemistry for?** The Nobel Prize in Chemistry in 2000 was awarded for the discovery of **fullerenes**, a new form of carbon molecules. 14. **What are OLEDs?** OLEDs (Organic Light Emitting Diodes) are a type of display technology that uses organic compounds to emit light when an electric current passes through them. 15. **What are bioplastics?**  Bioplastics are plastics made from renewable biomass sources, such as plant starches, and are often biodegradable. ### 11 – Pesticides 1. **What is the WHO pesticide hazard scale based on?** The WHO pesticide hazard scale is based on the toxicity and potential risks of pesticides to human health. 2. **What are some pesticides that are permitted for use in organic farming?** Some examples include **neem oil**, **pyrethrin**, and **diatomaceous earth**. 3. **What does DDT stand for? What was the chemical used for?** DDT stands for **Dichlorodiphenyltrichloroethane**. It was used as an insecticide, primarily to control malaria and typhus. 4. **What environmental problems have been associated with DDT use?** DDT caused the thinning of eggshells in birds of prey, leading to population declines, and it remains persistent in the environment. 5. **What was ‘Silent Spring’?**  "Silent Spring" is a book by Rachel Carson that exposed the dangers of DDT and other pesticides, leading to environmental awareness and change in pesticide policies. 6. **What species seemed to be most affected by DDT use?** Birds of prey, especially the **bald eagle** and **peregrine falcon**, were most affected by DDT. 7. **What is ‘Agent Orange’? Where and when was it used?** Agent Orange is a herbicide used by the U.S. military during the **Vietnam War** to defoliate forests and destroy crops. 8. **What problems are associated with Agent Orange?** Agent Orange caused long-term health problems for veterans and the Vietnamese population, including cancers and birth defects, due to the presence of **dioxins**. 9. **What is TCDD? Why is it a concern?** TCDD (Tetrachlorodibenzo-p-dioxin) is a highly toxic dioxin compound found in Agent Orange, causing severe health issues and environmental contamination. 10. **What is 2,4-D and what is it used for?**  2,4-D is a herbicide used to control broadleaf weeds, commonly in agriculture and forestry. 11. **What is glyphosate? Why is its use controversial? Is it safe? Does it cause autism?** Glyphosate is a widely used herbicide. Its use is controversial due to concerns about its potential to cause cancer (classified as a probable carcinogen by IARC) and its environmental impact. There is no evidence linking glyphosate to autism. --- ### 12 – Food Chemistry 1. **What is the difference between monosaccharides, disaccharides, and starches?** - **Monosaccharides** are simple sugars (e.g., glucose). - **Disaccharides** are two monosaccharides linked together (e.g., sucrose). - **Starches** are complex carbohydrates made of many glucose units. 2. **What are some common monosaccharides?** Examples include **glucose**, **fructose**, and **galactose**. 3. **What does ‘carbohydrate’ mean?** Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen. They serve as a primary energy source for the body. 4. **What natural sugar is sweetest?** **Fructose** is the sweetest natural sugar. 5. **What is HFCS-42? What is it made from? How?