Chemical Reactions and Heat Transfer

What is the primary characteristic of a chemical reaction?

• Two substances combine to form a new substance with different chemical and physical properties.

• A substance changes its physical state, like melting or freezing, but remains the same substance.

• Two substances are mixed together but do not chemically interact or change.

• A substance is broken down into its original, simpler components without forming anything new.

Which reactions releases energy?

• endothermic

• exothermic

Which reactions absorbs energy?

• endothermic

• exothermic

Which type of chemical reaction releases energy, often causing its surroundings to feel warmer?

• Endothermic reaction

• Exothermic reaction

• Neutralization reaction

• Decomposition reaction

How do instant heat packs generate warmth?

• They contain a small battery that produces heat.

• They absorb heat from the surrounding air.

• They use an exothermic reaction, often involving iron and oxygen, to release heat.

• They convert light energy into thermal energy.

What type of reaction pulls heat from the surroundings making it feel colder?

• exothermic

• Neutral

• decomposition

• endothermic

Why does an instant cold pack feel cold when activated?

• It releases cold gas that was stored inside.

• It absorbs heat from its surroundings through an endothermic reaction.

• It undergoes an exothermic reaction that cools the environment.

• It converts electrical energy into cold energy.

If the temperature dropped, which reactions type is it?

• endothermic

• exothermic

If the temperature goes up, which type of reaction is it?

• endothermic

• exothermic