General Chemistry 1 - First Periodical Examination Reviewer PDF

General Chemistry I – First Periodical Examination Reviewer Lesson 1: Properties of Matter e) State of Matter Physical Properties - The physical form in which a...

General Chemistry I – First Periodical Examination Reviewer Lesson 1: Properties of Matter e) State of Matter Physical Properties - The physical form in which a substance exists at room - A property of matter that can be temperature, such as; observed or measured without changing the identity of the Solid = matter has a definite matter. shape and volume Liquid = matter takes the shape - Anything that has mass and of its container and has a takes up space definite volume Gas = matter changes in both - States of matter: solid, liquid, shape and volume and gas f) Thermal Conductivity - Particle arrangement determines - The ability to transfer thermal the state of matter. energy from one area to another. - Physical properties identify g) Color matter through; h) Hardness a) Density - Resistance of a solid to - the amount of mass in a given scratching volume. Density equals mass divided by volume. i) Melting point - Temperature at which a solid - A substance is always the same change to a liquid at a given pressure and temperature regardless of the Chemical Property size of the sample of the substance. - A property of matter that describes a substance based on - The density of one substance is its ability to change into a new usually different from that of substance with different another substance. properties. b) Malleability - Can be observed with sense, and - The ability to be pounded into are not as easy to observe as thin sheets. physical properties. c) Ductility a) Combustibility (only when - The ability to be drawn or pulled fireworks explode) into a wire b) Flammability (only when d) Solubility wood burns) – How easily a - The ability to dissolve in substance ignites and burns another substance.  General Chemistry I – First Periodical Examination Reviewer - Particles in liquids are farther c) Reactivity (only when iron apart and can slide past each oxidizes – rust) – How other. readily a substance combines chemically with - Particles in gases are far apart other substances. and move freely in all i. Acids directions. ii. Bases iii. Oxidation Physical Change d) Toxicity – The degree to - A change that affects one or which a substance is more physical properties of a poisonous substance. - Do Not form new substances. Understanding Phase Changes - Can often be Undone - Matter can change from one state to another. Chemical Change - Phase changes are - A change that occurs when one transformations between states or more substances are changed of matter. into entirely new substances with different properties. - Common phase changes include - Can Not change back under melting, freezing, evaporation, normal conditions (some can be and condensation. changed back by other chemical means) - During a phase change, the arrangement of particles - 5 signs of chemical change changes. a) Odor Production – an odor - Energy is either absorbed or far different from what is released during a phase change. should smell like. The Particle Model of Matter b) Change in Temperature - All matter is made up of tiny, i. Exothermic (bond constantly moving particles. formation) – when energy is released - The state of matter depends on during the chemical how its particles are arranged. change - Particles in solids are closely ii. Endothermic (bond packed and vibrate in fixed breaking) – energy positions. is absorbed causing a decrease in the  General Chemistry I – First Periodical Examination Reviewer temperature of the reactant material. - Knowing whether a property is intensive or extensive can help c) Change in Color identify a substance. d) Formation of Bubbles – indicates the presence of a Lesson 2: Isotopes gas. Bubbles produced when boiling water is not a - atoms of a given element that differ chemical change. in the number of neutrons and consequently in mass. e) Formation of a Precipitate – When two liquids are Working with Atomic Notation combined and a solid is produced. Energy and Matter - Energy is the ability to do work or cause change. - Matter is anything that has mass and takes up space. - Energy can be transferred between objects or converted into different forms. - The law of conservation of energy states that energy cannot be created or destroyed. - The relationship between energy and matter is described by Einstein's famous equation, E=mc². Various ways of identifying Isotopes Intensive vs Extensive Properties a) Using atomic notation - Intensive properties are independent of the amount of Ex: 126 C or simply 12 C matter present. (temperature, color, density). b) Using mass notation - Extensive properties depend on Ex: Carbon-12 or C-12 the amount of matter present (mass, (read “carbon twelve” or “C volume, energy). twelve”)  General Chemistry I – First Periodical Examination Reviewer Finding the Number of Protons – radiation (tracers, The number of protons in an atom is biopharmaceuticals). equal to the atomic number of the element. - Radioactive isotopes are effective tracers because their radioactivity is Finding the Number of Electrons easy to detect. - The number of electrons in an atom is equal to the atomic number - A tracer is a substance that can be of an element, for neutrally charged used to follow the pathway of that species. This means the number of substance through some structure. electrons and the number of protons For instance, leaks in underground in an element are equal. water pipes can be discovered by running some tritium (H-3)-)- Finding the Number of Neutrons - containing water through the pipes The number of neutrons in an atom and then using a Geiger counter to can be calculated by subtracting the locate any radioactive tritium atomic number from the atomic subsequently present in the ground mass. around the pipes. (Recall that tritium is a radioactive isotope of Why are masses on the periodic hydrogen.) table usually expressed as decimal numbers? - Phosphorus-32 is used in plant sciences for tracking a plant's - Masses on the table are weighted uptake of fertilizer from the roots to averages of all known isotopes of the leaves. the element of interest - Co-60 (gamma source) and X-rays Parenthesis ( ) – indicates the most are used to irradiate many foods in stable isotope on the Periodic Table. the United States. Ionizing radiation Stable means “longest living” and can be used to kill food-borne suggests that the element of interest illnesses like salmonella and E. coli. is radioactive. Irradiating food can also prolong shelf-life, delay ripening, and Uses of Isotopes destroy insects. In addition, gamma/x-ray can sterilize foods I. Medicine making refrigeration unnecessary. II. Agriculture Often, sterilized food is served to III. Industry hospital patients who have impaired immune systems. - Radioisotopes (radioactive isotopes or radionuclides or radioactive nuclides) are used in two major ways: either for their radiation alone (irradiation, nuclear batteries) or for the combination of chemical properties and their  General Chemistry I – First Periodical Examination Reviewer Lesson 3: Writing Ions Ions - are atoms, or groups of atoms, with a charge (positive or Ion – an atom that has gained or negative). They have different lost electrons, formed when numbers of protons and electrons. electrons are exchanged in the formation of an ionic compound. Only electrons can move, and ions are made by gaining or losing I. Monoatomic ion – a single electrons. atom that has gained or lost electrons Predicting Ionic Charges a) Cation - formed when a i. Group 1A – lose 1 electron neutral atom loses one or to form 1+ ions more electrons ii. Group 2A - Loses 2 electrons to form 2+ ions b) Anion - formed when a iii. Group 3A – Loses 3 neutral atom gains one electrons to form 3+ ions or more electrons iv. Group 4A – Rarely forms ions (tend to share and can II. Polyatomic ion - a group of lose or gain 4 electrons) bonded atoms that have v. Group 5A – Gains 3 gained or lost electrons electrons to form 3- ions. vi. Group 6A – Gains 2 Transitional Metal Ions - a special electrons to form 2- ions. case of Cations, which can form vii. Group 7A – Gains 1 electron more than one type of ion. to form 1- ions. viii. Group 8A – Stable noble 9 Polyatomic Ions gases do not form ions ix. Group B elements – Many 1. Ammonium - NH₄⁺ transition elements have 2. Acetate - CH₃COO / C2H3O2− more than one possible 3. Cyanide - CN− oxidation state while some 4. Bicarbonate - HCO3− has only one. 5. Hydroxide - OH− x. Post-transition elements – 6. Nitrate - NO3− Have more than one 7. Carbonate - CO32− possible oxidation state. 8. Sulfate - SO42− 9. Phosphate - PO43− Naming Cations - Two methods can clarify when Lesson 4 (a): Chemical Names more than one charge is possible: and Formulas Atoms - electrically neutral. 1. Stock system – uses Roman Because there is the same number of numerals in parenthesis to protons (+) and electrons (-). indicate the numerical value.  General Chemistry I – First Periodical Examination Reviewer 2. Classical method – uses root Lesson 4 (b): Naming and Writing word with suffixes (-ous, -ic). Formulas for Ionic Compounds Does not give true value. - Cation - if the charge is always the Steps: same (like in the Group A metals) just write the name of the metal. 1. Write the formulas for the cation and anion, including CHARGES - Transition metals can have more 2. Check to see if charges are than one type of charge. balanced. 3. Balance charges, if necessary, using - Indicate their charge as a Roman subscripts. Use parentheses if you numeral in parenthesis after the need more than one of a polyatomic name of the metal (Use your Ion ion. Use the criss-cross method to Sheet) balance subscripts. - Exceptions: Some of the transition metals have only one ionic charge: Do not need to use Roman numerals for these: ✓ Silver is always 1+ (Ag1+) ✓ Cadmium and Zinc are always 2+ (Cd2+ and Zn2+) Naming Anions - Anions are always the same charge - Change the monatomic element ending to – ide Polyatomic ions - Groups of atoms that stay together and have an overall charge and one name. Naming Ionic Compounds - Usually end in –ate or -ite 1. Name the cation first, then a) Sulfite - SO32- the anion. b) Chromate - CrO42- 2. Monatomic cation – the c) Dichromate - Cr2O72- name of the element d) Phosphite - PO33- Ex: Ca2+ = calcium ion  General Chemistry I – First Periodical Examination Reviewer 3. Monatomic anion – root + - - Can’t use charges to figure out how ide many of each atom (there are no charges present) Ex: Cl- = chloride CaCl2 = calcium - Ionic compounds use charges to chloride determine how many of each. You have to figure out the charges and Naming Ionic Compounds may need to criss-cross numbers. (Metals with multiple oxidation states) - Molecular compounds: the name tells you the number of atoms. Uses - Some metals can form more than prefixes to tell you the exact number one charge (usually the transition of each element present. metals) 1 = mono- - Use a Roman Numeral in their 2 = di- name: 3 = tri- 4 = tetra- Ex: 5 = penta- Pb2+ is the lead (II) cation 6 = hexa- PbCl2 = lead (II) chloride 7 = hepta- 8 = octa- Things to look for: 9 = nona- 10 = deca- I. If cations have ( ), the number in parenthesis is - To write the name, write two words: their charge. Prefix & name Prefix & name -ide II. If anions end in -ide they are probably off the periodic - One exception is we don’t write table (Monoatomic). mono if there is only one of the first elements. III. If an anion ends in -ate or – ite, then it is polyatomic. Lesson 4 (d): Naming and Writing Formulas for Acids and Bases Lesson 4 (c): Naming and Writing Formulas for Molecular Compounds Acid Molecular Compounds - Compounds that give off hydrogen ions (H1+) when dissolved in water - Made of just non-metals (the Arrhenius definition) - The smallest piece is a molecule - Will start the formula with H. - Can’t be held together by opposite - There will always be some charge attraction Hydrogen next to an anion.  General Chemistry I – First Periodical Examination Reviewer - The anion determines the name. a) HClO2 (Hydrogen Chlorite) is chlorous acid, then HClO Rules for Naming Acids: Name it would be hypochlorous acid as a normal compound first Writing Acid Formulas 1. If the anion attached to hydrogen ends in -ide, put the 1. Hydrogen will be listed first. prefix hydro- and change -ide to -ic acid 2. The name will tell you the anion. HCl - hydrogen ion and chloride ion = hydrochloric acid 3. Be sure the charges cancel out. H2S hydrogen ion and sulfide ion = hydrosulfuric acid 4. Starts with prefix hydro? - there is no oxygen, -ide - If the anion has oxygen in it, then it ending for anion. ends in -ate or -ite 5. No prefix hydro? 2. Change the suffix -ate to -ic acid -ate anion comes from –ic (use no prefix) ending Example: HNO3 Hydrogen and -ite anion comes from –ous nitrate ions = Nitric acid ending 3. Change the suffix -ite to -ous Names and Formulas for Bases acid (use no prefix) - A base is an ionic compound that Example: HNO2 Hydrogen and produces hydroxide ions (OH1-) nitrite ions = Nitrous acid when dissolved in water (the Arrhenius definition) 4. If the acid has 1 more oxygen than the –ic acid, add the prefix - Bases are named the same way as per- other ionic compounds: a) HClO3 (Hydrogen Chlorate) - The name of the cation (which is a is chloric acid metal) is followed by the name of the anion (which will be hydroxide). b) HClO4 would be perchloric acid - To write the formula: i. Write the symbol for the 5. If there is 1 less oxygen than the metal cation -ous acid, add the prefix hypo- ii. Followed by the formula for the hydroxide ion (OH1-)  General Chemistry I – First Periodical Examination Reviewer iii. Then use the criss-cross - Is the percent by mass of each method to balance the element in a formula charges. - First, figure out the total mass of each element to get the Formula Mass. Lesson 4 (e): The Laws Governing - Second, divide the Mass of the Formulas and Names particular element by the total Formula Mass - Third, multiply that number by 100 Law of Definite Proportions- in a to get the percentage. sample of a chemical compound, the masses of the elements are Formula: always in the same proportions. 0⁄ 𝐸 = (TG) −𝑥100% = H2O (water) and H2O2 (hydrogen 0 (MM) peroxide) Law of Multiple Proportions- E = element Dalton stated that whenever two TG = total grams of the element elements form more than one MM = molar mass compound, the different masses of one element that combine with the same mass of the other element are Lesson 6: Finding Empirical Formula, in the ratio of small whole numbers. Molecular Formula, Molar Mass, and Empirical Mass Reminder: 1. In an ionic compound, the net I. Empirical Mass = adding all the ionic charge is zero (criss-cross atomic mass of the elements method) (simplest ratio) 2. An -ide ending generally II. Molar Mass = adding the atomic indicates a binary compound masses of a given compound (based 3. An -ite or -ate ending means on the molecular formula) there is a polyatomic ion that III. Empirical Formula = the simplest has oxygen whole number ratio of the 4. Prefixes generally mean molecular formula. molecular; they show the IV. Molecular Formula = mm/em number of each atom (molar mass divided by empirical 5. A Roman numeral after the mass) name of a cation is the ionic charge of the cation - Exception: Formula when the grams are given Lesson 5: Chemical Quantities – Percent 0⁄ 𝐶𝑜𝑚𝑝 = 𝑚 (1 mol) 0 (𝑔)−> Composition (grams E)  General Chemistry I – First Periodical Examination Reviewer M(g) = mass of the element in grams The limiting reactant determines how much product is produced. E = element Once the limiting reactant is used up the reaction stops. Lesson 7: Stoichiometry The theoretical yield is the maximum amount of product that could be formed, based on the Road Map limiting reactant. Solving Limiting Reactant Problems - When you are given amounts of two or more reactants you MUST treat it as a limiting reactant problem. - To Solve: Do the 4 steps of stoichiometry with each amount of reactant, solving for the same product. - The reactant that produces the least amount of product (theoretical Lesson 8: Limiting Reactants and yield) is the limiting reactant. Excess Lesson 9: Gas Laws Stoichiometric amounts of reactants mean they are present in a mole ratio that corresponds exactly Gas law discovers and tackles the to the mole ratio predicted by the relationship of pressure, balanced chemical equation. temperature, volume, and amount of gas. This means that when a reaction is complete, there are no reactants left. I. Boyle’s Law The reactant, which is completely - Relationship between pressure and used up in a chemical reaction is volume called the limiting reactant. - Inverse relationship (As the volume of the gas increases, the Reactants that remain after the pressure decreases – vice versa) limiting reaction is over are called excess reactants.  General Chemistry I – First Periodical Examination Reviewer II. Charle’s Law - Relationship between volume and temperature - Direct relationship (As the temperature increases, the volume increases – vice versa) III. Avogadro’s Law - Relationship between volume and gas (number of moles) - Direct relationship - For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant. IV. PV=nRT - The ideal gas law relates the macroscopic properties of ideas gases. - sets variables of that gas's pressure (P) times volume (V) equal to the amount in moles (n) of that gas multiplied by the ideal gas constant (R – 0.0821) multiplied by its temperature (T).