Unit 4 Review

Front

What is a chemical reaction?

Back

A process where substances (reactants) undergo a transformation to form new substances (products) with different properties.

Front

What is a physical change?

Back

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

Front

How does temperature affect chemical reactions?

Back

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

Front

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

Back

A chemical change results in the formation of new substances, while a physical change does not change the chemical identity of a substance.

Front

What is mass conservation in physical changes?

Back

In a physical change, the total mass of the substance remains the same before and after the change.

Front

What is an example of a physical change?

Back

Melting ice is a physical change; the ice changes state from solid to liquid but remains water.

Front

What is an example of a chemical change?

Back

Burning wood is a chemical change; it transforms into ash, smoke, and gases, which are different substances.

Front

What is the role of repetition in scientific investigations?

Back

Repetition helps verify results and ensures that findings are reliable and not due to random chance.

Front

What is the significance of observing changes in properties during a chemical reaction?

Back

Changes in properties, such as color, temperature, or state, indicate that a chemical reaction may have occurred.

Front

What is the definition of density?

Back

Density is the mass of a substance divided by its volume, often expressed in grams per cubic centimeter (g/cm³).