Chemical Reactions Quiz

Which of the following best describes an exothermic reaction?

• It doesn't involve any heat changes.

• It remains at a constant temperature.

• It releases heat to the surroundings.

• It absorbs heat from the surroundings.

When you feel warmth radiating from a chemical reaction, it's most likely:

• An endothermic reaction.

• An exothermic reaction.

• A reversible reaction.

• A neutral reaction.

Combustion reactions are typically:

• Irreversible.

• Endothermic.

• Exothermic.

• Neutral.

Which of the following is an example of an exothermic reaction?

• Melting ice.

• Burning wood.

• Dissolving salt in water.

• Photosynthesis.

Endothermic reactions:

• Release heat to the surroundings.

• Don't involve any heat changes.

• Absorb heat from the surroundings.

• Only occur in biological systems.

When ice melts, it ____ heat from the surroundings.

• Doesn't affect

• Releases

• Generates

• Absorbs

Which of the following is an example of an endothermic reaction?

• Mixing vinegar and baking soda.

• Boiling water.

• Rusting of iron.

• Condensation of water vapor.

Breaking bonds in chemical reactions usually ____ energy.

• Releases

• Neutralizes

• Stabilizes

• Requires

Which of the following is true about exothermic reactions?

• They always involve a phase change.

• They always involve a release of energy to the surroundings.

• They always involve an increase in temperature.

• They always involve a decrease in temperature.

In an endothermic reaction, the energy of the products is ____ than the energy of the reactants.

• Lower

• Higher

• The same

• Variable