Unit 5 Practice

Front

What is a physical change?

Back

A physical change is a change in an item's properties like its shape, size, or density.

Front

What is the dependent variable in an experiment?

Back

The dependent variable is the variable that is measured or observed in an experiment, such as reaction time in the context of playing video games.

Front

What is the independent variable in an experiment?

Back

The independent variable is the one thing you change on purpose in an experiment.

Front

What is a clue that a chemical reaction has taken place?

Back

Clues that a chemical reaction has taken place include changing color, formation of a gas, and formation of a precipitate.

Front

Which of the following is NOT a clue that a chemical reaction has taken place?

Back

Changing size is NOT a clue that a chemical reaction has taken place.

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 composition, while a chemical change results in the formation of new substances.

Front

Give an example of a physical change.

Back

An example of a physical change is melting ice into water.

Front

What is a chemical reaction?

Back

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.

Front

What is a precipitate?

Back

A precipitate is a solid that forms and settles out of a liquid mixture during a chemical reaction.

Front

What does it mean to control a variable in an experiment?

Back

To control a variable means to keep it constant and not change it during the experiment.