7th grade 2.1 Test

Front

What is reactivity in chemistry?

Back

Reactivity refers to the ability of a substance to undergo a chemical reaction and form new substances. It is a property that describes how readily a substance reacts with other substances.

Front

What is a chemical change?

Back

A chemical change is a process that results in the formation of new chemical substances. It involves breaking and forming bonds between atoms.

Front

What is evidence of a chemical change?

Back

Evidence of a chemical change includes color change, temperature change, gas production, formation of a precipitate, or the appearance of new substances.

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. Examples include changes in state, shape, or size.

Front

What happens when vinegar is mixed with baking soda?

Back

When vinegar is mixed with baking soda, a chemical reaction occurs that produces carbon dioxide gas, resulting in bubbling.

Front

What is an example of a physical change?

Back

Mixing oil and vinegar is an example of a physical change because the substances retain their original properties and can be separated.

Front

What is the process of baking bread an example of?

Back

Baking bread is an example of a chemical change because it involves the transformation of ingredients into new substances through heat.

Front

What does it mean when soot appears after a fire?

Back

The appearance of soot after a fire indicates that a chemical change has occurred, as new substances (like carbon) are formed during combustion.

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 composition of the substance.

Front

What is density?

Back

Density is a physical property defined as mass per unit volume of a substance, often expressed in grams per cubic centimeter (g/cm³).