Unit 4 Review

Front

What is the Law of Conservation of Mass?

Back

The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction. The total mass of the reactants equals the total mass of the products.

Front

How does heat flow between two touching objects?

Back

Heat flows from the object with a higher temperature to the object with a lower temperature until thermal equilibrium is reached.

Front

What happens to the mass of a liquid in a thermometer when it is heated?

Back

The mass of the liquid stays the same, even though the volume may increase.

Front

What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition.

Front

What is an example of a physical change?

Back

Dissolving sugar in water is an example of a physical change, as the sugar can be recovered and the chemical composition remains unchanged.

Front

How does temperature affect chemical reactions?

Back

Lower temperatures generally reduce the rate of chemical reactions, while higher temperatures can increase the rate of reactions.

Front

What is thermal equilibrium?

Back

Thermal equilibrium is the state in which two objects in contact with each other reach the same temperature, resulting in no net heat flow between them.

Front

What is the difference between a physical change and a chemical change?

Back

A physical change alters the form or appearance of a substance without changing its chemical composition, while a chemical change results in the formation of new substances.

Front

What is an example of a chemical change?

Back

Burning wood is an example of a chemical change, as it produces ash, smoke, and gases, changing the original substance into new substances.

Front

What is the role of temperature in the freshness of food?

Back

Lower temperatures slow down chemical reactions that cause food to spoil, helping to keep it fresh longer.