Chemical Reactions

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. Example: Freezing water.

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What is a catalyst?

Back

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.

Tags

NGSS.HS-PS1-5

Front

What are some signs that a chemical reaction has occurred?

Back

Signs of a chemical reaction include color change, odor change, and change in properties.

Tags

NGSS.MS-PS1-2

Front

What happens to the number of atoms in a chemical reaction?

Back

The number of atoms remains the same before and after a chemical reaction; they are rearranged but not created or destroyed.

Tags

NGSS.MS-PS1-5

Front

What is a molecule?

Back

A molecule is made of two or more atoms bonded together.

Tags

NGSS.MS-PS1-1

Front

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

Back

A physical change affects physical properties without changing the substance's identity, while a chemical change results in the formation of new substances.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS1-5

Front

What is an example of a chemical change?

Back

Burning wood is an example of a chemical change, as it transforms the wood into ash and smoke.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

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.

Tags

NGSS.MS-PS1-5

Front

What is an atom?

Back

An atom is the smallest unit of an element that retains the properties of that element.

Tags

NGSS.MS-PS1-1

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.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5