8. GL Chem Mock

What is combustion?

• A slow reaction that does not produce heat or light.

• A method of cooling substances using water.

• Combustion is a rapid chemical reaction between a fuel and oxygen that produces heat and light.

• A process that only occurs in the absence of oxygen.

Which of the following is an example of thermal decomposition?

• Decomposition of calcium carbonate (CaCO3) into calcium oxide (CaO) and carbon dioxide (CO2) when heated.

• Decomposition of sodium chloride (NaCl) into sodium (Na) and chlorine (Cl) when heated.

• Decomposition of glucose (C6H12O6) into carbon dioxide (CO2) and water (H2O) when heated.

• Decomposition of water (H2O) into hydrogen (H2) and oxygen (O2) when heated.

What happens during oxidation?

• A substance remains unchanged and does not interact with other elements.

• A substance absorbs energy and increases in temperature.

• A substance gains electrons and may lose oxygen or gain hydrogen.

• A substance loses electrons and may gain oxygen or lose hydrogen.

Which reaction type involves a more reactive element displacing a less reactive one?

• Double displacement reaction

• Single displacement reaction

• Combustion reaction

• Synthesis reaction

What is diffusion in terms of the particle model?

• Diffusion is the transfer of energy between particles without movement.

• Diffusion is the process of particles settling at the bottom of a container.

• Diffusion is the movement of particles from high to low concentration due to random motion.

• Diffusion is the movement of particles from low to high concentration.

Which of the following describes an exothermic reaction?

• A reaction that absorbs energy, typically in the form of heat.

• A reaction that occurs spontaneously without energy change.

• A reaction that produces light without heat release.

• A reaction that releases energy, typically in the form of heat.

What is an endothermic reaction?

• A reaction that releases heat.

• An endothermic reaction is a reaction that absorbs heat.

• A reaction that occurs without any temperature change.

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

What does the law of conservation of mass state?

• Mass is only relevant in solid substances.

• Mass is conserved in chemical reactions; it cannot be created or destroyed.

• Mass is lost during physical changes.

• Mass can be created in chemical reactions.

What happens to mass during a chemical reaction?

• Mass is irrelevant in a chemical reaction.

• Mass is destroyed during a chemical reaction.

• Mass increases during a chemical reaction.

• Mass is conserved during a chemical reaction.

What is the role of a catalyst in a chemical reaction?

• A catalyst is consumed during the reaction and cannot be reused.

• A catalyst speeds up a chemical reaction by lowering activation energy.

• A catalyst changes the products of the reaction to create new substances.

• A catalyst slows down a chemical reaction by increasing activation energy.