Chemical Reactions and Changes

Front

What is a chemical change?

Back

A process in which one or more substances are transformed into entirely new substances with different properties.

Front

What is an example of a chemical change?

Back

Burning of wood, rusting of iron, cooking of an egg.

Front

What happens during a burning reaction?

Back

A substance combines with oxygen, and chemical energy is changed to thermal, light, and sound energy.

Front

What is an exothermic reaction?

Back

A chemical reaction in which thermal energy is given out, causing the temperature to rise.

Front

What is formed when a substance burns in oxygen?

Back

An oxide is formed.

Front

What is an oxidation reaction?

Back

A reaction in which a substance combines with oxygen.

Front

What happens when potassium reacts with water?

Back

Potassium reacts with water to form potassium hydroxide and hydrogen.

Front

What occurs when magnesium is added to dilute hydrochloric acid?

Back

The test tube gets hot, indicating an exothermic reaction.

Front

What does exothermic mean in a chemical process?

Back

It means heat is moving outside, and it is a heat-generating chemical reaction.

Front

What do exothermic reactions release?

Back

They release energy from the chemicals into the surroundings.