Chemistry Review PDF

CHEMISTRY REVIEW Page 1 Questions ​ 1.​ Define atomic number and atomic mass. ​ ​ Atomic Number: The number of protons in the nucleus of an atom, which determines the element’s identity. ​ ​ Atomic Mass: The total mass of an atom, approximately equal to the sum of pro...

CHEMISTRY REVIEW Page 1 Questions ​ 1.​ Define atomic number and atomic mass. ​ ​ Atomic Number: The number of protons in the nucleus of an atom, which determines the element’s identity. ​ ​ Atomic Mass: The total mass of an atom, approximately equal to the sum of protons and neutrons in the nucleus. It is measured in atomic mass units (amu). ​ 2.​ Name the 3 subatomic particles and include their function, relative mass, and charge. ​ ​ Protons: Positive charge (+1), mass ~1 amu, determines the element’s identity. ​ ​ Neutrons: No charge (neutral), mass ~1 amu, stabilizes the nucleus. ​ ​ Electrons: Negative charge (-1), negligible mass (~0 amu), involved in chemical bonding and reactions. ​ 3.​ How is the periodic table organized? The periodic table is organized by increasing atomic number (proton count). Elements are grouped into periods (rows) and groups/families (columns) based on similar chemical properties. ​ 4.​ Define “valence shell.” The outermost electron shell of an atom, containing the electrons involved in bonding. ​ 5.​ What kind of elements become cations? Anions? ​ ​ Cations: Metals, as they lose electrons. ​ ​ Anions: Non-metals, as they gain electrons. ​ 6.​ Name the families on the periodic table. ​ ​ Alkali metals ​ ​ Alkaline earth metals ​ ​ Transition metals ​ ​ Halogens ​ ​ Noble gases ​ ​ Chalcogens (oxygen family) Page 2 Questions ​ 7.​ Charges for families and examples of elements: ​ ​ Alkali metals (Group 1): +1 (e.g., Sodium - Na) ​ ​ Alkaline earth metals (Group 2): +2 (e.g., Calcium - Ca) ​ ​ Chalcogens (Group 16): -2 (e.g., Oxygen - O) ​ ​ Halogens (Group 17): -1 (e.g., Chlorine - Cl) ​ ​ Noble gases (Group 18): 0 (e.g., Neon - Ne) ​ 8.​ Examples from the families: Refer to #7 for examples. ​ 9.​ Stock system elements and formulas: Examples include: ​ ​ Iron (II) oxide: FeO ​ ​ Copper (II) sulfate: CuSO₄ ​ ​ Lead (II) nitrate: Pb(NO₃)₂ ​ 10.​ Define covalent and ionic compounds. ​ ​ Covalent compounds: Formed by sharing electrons between nonmetals (e.g., H₂O). ​ ​ Ionic compounds: Formed by the transfer of electrons between metals and nonmetals (e.g., NaCl). ​ 11.​ Why do atoms form bonds? To achieve stability by filling their valence shell, often by completing the octet rule. ​ 12.​ Maximum electrons in the first 3 electron shells: ​ ​ 1st shell: 2 electrons ​ ​ 2nd shell: 8 electrons ​ ​ 3rd shell: 18 electrons ​ 13.​ Bond between X and Y: ​ ​ X loses electrons (cation), Y gains electrons (anion). ​ ​ Bond type: Ionic bond. Examples: NaCl, MgO. ​ 14.​ Define diatomic molecule: A molecule consisting of two atoms of the same element (e.g., H₂, O₂, N₂). Page 3 Questions ​ 15.​ Name the ionic compounds: ​ ​ PbCl₂: Lead (II) chloride ​ ​ K₂S: Potassium sulfide ​ ​ NiBr₃: Nickel (III) bromide ​ ​ KI: Potassium iodide ​ 16.​ Name the covalent compounds: ​ ​ CCl₄: Carbon tetrachloride ​ ​ NO₃: Nitrogen trioxide ​ ​ PCl₃: Phosphorus trichloride ​ ​ CS₂: Carbon disulfide ​ 17.​ Name the 7 diatomic molecules: ​ ​ H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂ Page 4 Questions ​ 1.​ Law of conservation of mass: Matter is neither created nor destroyed in a chemical reaction. ​ 2.​ Define acid, base, pH, and indicator: ​ ​ Acid: Donates H⁺ ions, pH < 7. ​ ​ Base: Donates OH⁻ ions, pH > 7. ​ ​ pH: Scale measuring acidity/basicity. ​ ​ Indicator: Substance that changes color based on pH. ​ 3.​ Define chemical reaction: A process in which substances (reactants) are transformed into new substances (products) with different properties. ​ 4.​ Five types of reactions and examples: ​ ​ Synthesis: A + B → AB (e.g., 2H₂ + O₂ → 2H₂O) ​ ​ Decomposition: AB → A + B (e.g., 2H₂O → 2H₂ + O₂) ​ ​ Single displacement: A + BC → AC + B (e.g., Zn + HCl → ZnCl₂ + H₂) ​ ​ Double displacement: AB + CD → AD + CB (e.g., NaCl + AgNO₃ → NaNO₃ + AgCl) ​ ​ Combustion: Hydrocarbon + O₂ → CO₂ + H₂O ​ 5.​ Neutralization: Reaction of acid and base to form water and salt (e.g., HCl + NaOH → NaCl + H₂O). ​ 6.​ Balance reactions: a) 2PbO → 2Pb + O₂ b) Na₃N → 3Na + N₂ c) Sn + 2Cl₂ → SnCl₄ d) Zn + H₂SO₄ → ZnSO₄ + H₂ e) HNO₃ + Mg(OH)₂ → Mg(NO₃)₂ + H₂O ECOLOGY REVIEW 1. Define the following terms: ​ ​ Ecology: The study of interactions between organisms and their environment. ​ ​ Ecologist: A scientist who studies ecology. ​ ​ Ecosystem: A community of living organisms interacting with their non-living environment. ​ ​ Environment: The external surroundings and conditions in which an organism lives. ​ ​ Nutrient cycle: The movement and exchange of organic and inorganic matter back into the production of living matter (e.g., carbon, nitrogen cycles). ​ ​ Biodiversity: The variety of life in a particular ecosystem or on Earth as a whole. ​ ​ Sustainability: Meeting the needs of the present without compromising the ability of future generations to meet their needs. 2. Another term for non-living is: ​ ​ Abiotic. 3. What is a producer? ​ ​ A producer is an organism, like a plant or algae, that makes its own food through photosynthesis or chemosynthesis. 4. True/False: All consumers depend on producers. Explain. ​ ​ True. Producers are the base of the food chain, providing energy and nutrients for primary consumers (herbivores) and indirectly for higher-level consumers. 5. How do decomposers contribute to an ecosystem? ​ ​ Decomposers break down dead organisms, recycling nutrients like nitrogen and carbon back into the soil for plants to use. 6. What is always found at the base of the food chain? ​ ​ Producers, such as plants, algae, or phytoplankton. 7. What is a top carnivore? ​ ​ A top carnivore, or apex predator, is a predator at the top of the food chain that has no natural predators (e.g., lions, orcas). 8. Draw (and label) a diagram which represents the carbon cycle. ​ ​ Key components include: ​ ​ Photosynthesis: Plants absorb CO₂. ​ ​ Respiration: CO₂ is released by organisms. ​ ​ Decomposition: Decomposers release CO₂. ​ ​ Combustion: Burning fossil fuels adds CO₂ to the atmosphere. 9. What is the chemical reaction for cellular respiration? ​ ​ C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP). 10. In what type of organism does cellular respiration occur? ​ ​ Cellular respiration occurs in all organisms, including plants, animals, fungi, and microbes. 11. Name a source of excess atmospheric CO₂. ​ ​ Combustion of fossil fuels (e.g., cars, factories, power plants). 12. What is the greenhouse effect? Name 5 consequences of greenhouse gases. ​ ​ The greenhouse effect is the trapping of heat in Earth’s atmosphere by gases like CO₂, methane, and water vapor. ​ ​ Consequences: ​ 1.​ Global warming. ​ 2.​ Melting ice caps. ​ 3.​ Rising sea levels. ​ 4.​ Extreme weather events. ​ 5.​ Loss of biodiversity. 13. Draw and explain the steps in the nitrogen cycle. ​ ​ Steps: ​ 1.​ Nitrogen fixation: Conversion of N₂ to ammonia by bacteria or lightning. ​ 2.​ Nitrification: Ammonia is converted to nitrites, then nitrates. ​ 3.​ Assimilation: Plants absorb nitrates. ​ 4.​ Ammonification: Decomposers release ammonia from organic matter. ​ 5.​ Denitrification: Bacteria convert nitrates back to N₂ gas. 14. What are the consequences of too many nitrates in the atmosphere? ​ ​ Excess nitrates can lead to eutrophication, acid rain, and air pollution. 15. Identify all the steps in eutrophication. ​ ​ ​ 1.​ Excess nutrients (like nitrates/phosphates) enter water. ​ 2.​ Algae bloom grows. ​ 3.​ Algae die and decompose, consuming oxygen. ​ 4.​ Hypoxia (low oxygen) kills aquatic life. 16. How does a green plant produce its own food? ​ ​ Through photosynthesis: converting sunlight, CO₂, and water into glucose and oxygen. 17. Explain the phenomenon known as bioaccumulation and give an example. ​ ​ Bioaccumulation is the buildup of toxic substances (like mercury) in an organism. ​ ​ Example: Mercury in fish increases as it moves up the food chain. 18. Name three density-dependent factors and three density-independent factors. ​ ​ Density-dependent factors: Disease, competition, predation. ​ ​ Density-independent factors: Natural disasters, temperature, pollution. 19. Describe the evolution of a population introduced to an environment. ​ ​ Graph explanation: ​ 1.​ Lag phase: Slow growth as organisms adapt. ​ 2.​ Exponential growth: Rapid increase due to resources. ​ 3.​ Carrying capacity: Growth stabilizes as resources are limited. ​ ​ Graph typically shows an S-shaped curve. 20. Describe the conditions needed to attain carrying capacity. ​ ​ Balanced resource availability, predation, disease control, and sustainable reproduction rates. 21. What are possible consequences for introducing a new species into an ecosystem? ​ ​ Consequences: ​ 1.​ Competition with native species. ​ 2.​ Predation on native species. ​ 3.​ Ecosystem imbalance. ​ 4.​ Decline or extinction of native species. 22. In what 5 ways do exotic species infiltrate ecosystems? ​ 1.​ Transportation (ships, planes). ​ 2.​ Pet trade. ​ 3.​ Agricultural practices. ​ 4.​ Habitat modification. ​ 5.​ Intentional release. 23. Explain the concept of sustainability. Give an example of a sustainable practice. ​ ​ Sustainability ensures resources are conserved for future generations. ​ ​ Example: Using renewable energy sources like solar power. 24. How does biodiversity affect sustainability? ​ ​ Greater biodiversity ensures ecosystem stability and resilience to changes. 25. What affects biodiversity? ​ ​ Habitat destruction, pollution, overharvesting, climate change, and invasive species. PHYSICS REVIEW