Chemistry Chapter 7 - Chemical Reactions - Quiz Questions (#1- #5)
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Q1-1: State the definition for REACTANT. |
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A1-1: A substance or a molecule that participates in a chemical reaction. (Note: usually found on the LEFT side of a chemical equation.) |
Q1-2: State the definition for PRODUCT. |
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A1-2: A substance that forms in a chemical reaction. (Note: usually found on the RIGHT side of a chemical equation.) |
Q1-3: State the definition for CHEMICAL ENERGY. |
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A1-3: The energy released when a chemical compound reacts to produce new products. |
Q1-4: State the definition for EXOTHERMIC REACTION. |
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A1-4: A chemical reaction in which energy is released to the surroundings as heat. (Whenever you see fire you have seen an exothermic reaction!) |
Q1-5: State the definition for ENDOTHERMIC REACTION. |
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A1-5: A chemical reaction that requires energy input. (This reaction ABSORBS heat -- ie, it gets cold.) |
Q1-6: List three signs that could indicate that a chemical reaction is taking place. |
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A1-6: a) formation of a gas; b) formation of a solid (ie, a "precipitate"); c) release of energy in the form of heat or light |
Q1-7: List four forms of energy that may be absorbed or released during a chemical reaction. |
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A1-7: heat, light, electricity, sound |
Q1-8: In the following equation, what are the reactants and what are the products? |
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A1-8: a) reactants: CH4 + 2O2 [methane & oxygen]; b)products: CO2 + 2H2O [carbon dioxide & water] |
Q2-1: What is a CHEMICAL EQUATION? |
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A2-1: A representation of a chemical reaction that uses symbols to show the relationship between the reactants and the products. |
Q2-2: What is a COEFFICIENT? |
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A2-2: A number that appears BEFORE a reactant or product that tells how many molecules of that substance are used in the reaction. |
Q2-3: What is a SUBSCRIPT? |
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A2-3: A number placed AFTER a chemical symbol that tells how many atoms of that element appear in the compound. |
Q2-4: Balance the following chemical equation ---- a) |
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Q2-4: Balance the following chemical equation ---- b) |
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Q2-4: Balance the following chemical equation ---- c) |
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Q2-4: Balance the following chemical equation ----- d) |
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Q2-5: Balance the following chemical equation ---- e) |
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Q2-4: Balance the following chemical equation ---- f) |
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Q2-4: Balance the following chemical equation ---- g) |
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Q2-4: Balance the following chemical equation ---- h) |
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Q2-4:Balance the following chemical equation ---- i) |
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Q2-4: Balance the following chemical equation ---- j) |
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Q2-4: Balance the following chemical equation ---- k) |
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Q2-4: Balance the following chemical equation ---- l) |
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Q3-1: Define the term SYNTHESIS REACTION and give an example. |
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A3-1: a) Two or more substances combine to form a new substance. b) N2 + 3 H2 à 2 NH3 |
Q3-2: Define the term DECOMPOSITION REACTION and give an example. |
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A3-2: a) When a single compound is broken down to form two or more simpler substances; b) 2 H2O à 2 H2 + O2 |
Q3-3: Define the term COMBUSTION REACTION and give an example. |
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A3-3: a) The oxidation reaction of an organic compound, in which heat is released; b) CH4 + 2 O2 à CO2 + 2 H2O |
Q3-4: Define the term SINGLE-DISPLACEMENT REACTION and give an example. a) Definition: |
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A3-4: a) Where one element or radical takes the place of another element or radical in a compound; b) 2 Cu2O + C à 4 Cu + CO2 |
Q3-5: Define the term ELECTROLYSIS. |
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A3-5: The breaking down of water into hydrogen and oxygen by passing electric current through water. |
Q3-6: Define the term DOUBLE-DISPLACEMENT REACTION and give an example. a) Definition: |
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A3-6: a) A reaction in which two compounds exchange ions; b) FeS + 2 HCl à H2S + FeCl2 |
Q3-7: What is a FREE RADICAL? |
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A3-7: An atom or a group of atoms that has one unpaired electron. (Hydrogen is often a free radical because it only has one electron available for bonding.) |
Q3-8: Define the term REDOX REACTION and give an example. |
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A3-8: a) This is an oxidation-reduction reaction in which one species is oxidized (loses electrons) and another is reduced (gains electrons); b) iron rusting to produce iron oxide |
Q4-1: List four factors that affect the rate of a reaction. |
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A4-1: temperature, surface area, concentration, pressure |
Q4-2: Define the term CATALYST. |
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A4-2: A substance that changes the rate of a chemical reaction without being consumed or changed significantly. |
Q4-3: Define the term ENZYME. |
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A4-3: A type of protein that speeds up metabolic reactions in plants and animals without being permanently changed or destroyed. |
Q4-4: Define the term SUBSTRATE. |
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A4-4: The reactant in reactions catalyzed by enzymes. |
Q4-5: Substances that slow reactions are called ____________________. |
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A4-5: inhibitors |
Q4-6: When you open a soda bottle, what change occurs that allows the dissolved carbon dioxide in the soda to come out of solution? |
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A4-6: You have changed the pressure. As long as the cap is on the bottle, the carbon dioxide dissolved in the water is spread out evenly throughout the bottle due to the pressure in side the bottle. Opening the bottle allows the gas to escape from a high pressure environment inside the bottle to a lower pressure area outside the bottle. |
Q4-7: Define the term CHEMICAL EQUILIBRIUM. |
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A4-7: A state of balance in which the rate of a forward reaction equals the rate of the reverse reaction and the concentrations of products and reactants remain unchanged. |
Q4-8: What is Le Chatelier’s principle? |
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A4-8: If a change is made to a system in chemical equilibrium, the equilibrium shifts to oppose the change until an new equilibrium is reached. |
Q4-9: Compare a catalyst and an inhibitor. |
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A4-9: A catalyst speeds up a reaction, an inhibitor slows it down. |
Q4-10: The Haber process uses Le Chatelier’s principle to produce more ammonia. What two things do they have to do to the reaction to get more ammonia as a product? |
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A4-10: high pressure and low temperature |
Q5-1: Chemical reactions occur when substances undergo __________ changes to form new substances. |
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A5-1: chemical |
Q5-2: Chemical reactions involve changes in __________. |
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A5-2: energy |
Q5-3: A chemical equation uses __________ to represent a chemical reaction |
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A5-3: symbols |
Q5-4: . A balanced equation tells you the _______ ______, or proportion of ________ and ________, in a chemical reaction. |
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A5-4: mole ratio ..... reactants ... products |
Q5-5: List four types of chemical reactions. |
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A5-5: synthesis, decomposition, single-replacement, double-displacement |
Q5-6: Free-radical reactions and redox reactions can be understood as changes in the number of __________ that atoms have. |
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A5-6: electrons |
Q5-7: Anything that increases _________ between particles will increase the rate of a reaction. |
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A5-7: contact |
Q5-8: Process that go in both directions may result in ______________. |
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A5-8: chemical equilibrium |