Chemical Reactions

What is the law of conservation of mass?

• Mass can be created or destroyed in a chemical reaction.

• Mass remains constant in a closed system during a chemical reaction.

• Mass can change forms but cannot be created or destroyed.

• Mass is only relevant in physical changes, not chemical reactions.

What does it mean for a chemical equation to be balanced?

• A balanced chemical equation has different numbers of atoms on each side of the equation.

• A balanced chemical equation has the same number of each type of atom on both sides of the equation, indicating that mass is conserved during the reaction.

• A balanced chemical equation shows that energy is lost during the reaction.

• A balanced chemical equation can have unequal charges on both sides.

What are reactants in a chemical reaction?

• Substances that are produced in a chemical reaction.

• Starting materials that undergo change to form products.

• Elements that cannot be changed during a reaction.

• The energy required to initiate a chemical reaction.

What is an endothermic reaction?

• A chemical reaction that releases heat to its surroundings.

• A chemical reaction that absorbs heat from its surroundings.

• A chemical reaction that occurs at a constant temperature.

• A chemical reaction that produces light energy.

What are products in a chemical reaction?

• Substances that are consumed during the reaction.

• Substances that are formed as a result of a chemical reaction.

• Elements that are mixed together before the reaction.

• Catalysts that speed up the reaction.

What role do catalysts play in chemical reactions?

• Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process.

• Catalysts are substances that slow down chemical reactions.

• Catalysts are used to change the color of chemical reactions.

• Catalysts are substances that are consumed during the reaction.

What is stoichiometry in chemistry?

• The study of chemical bonds and their properties.

• The calculation of reactants and products in chemical reactions based on the balanced equation.

• The process of mixing different chemicals to create a reaction.

• The measurement of temperature and pressure in chemical reactions.

What is an exothermic reaction?

• A chemical reaction that absorbs heat from its surroundings.

• A chemical reaction that releases heat to its surroundings.

• A reaction that occurs only in the presence of a catalyst.

• A reaction that requires energy input to proceed.

What is an example of a simple chemical reaction?

• The combustion of methane: CH₄ + 2O₂ → CO₂ + 2H₂O.

• The rusting of iron: 4Fe + 3O₂ → 2Fe₂O₃.

• The reaction of vinegar and baking soda: CH₃COOH + NaHCO₃ → CO₂ + H₂O + NaCH₃COO.

• The decomposition of water: 2H₂O → 2H₂ + O₂.

What is a chemical reaction?

• A process where substances are mixed without any change.

• A process in which one or more substances (reactants) are converted into one or more different substances (products) through the breaking and forming of chemical bonds.

• A method of separating mixtures into their individual components.

• A physical change that alters the state of a substance.