Science Assessment ~ Topics ~ Substances, Chemical Reactions, and Conservation of Matter

Log In | Register

Topic: Substances, Chemical Reactions, and Conservation of Matter

Below is a list of key ideas related to Substances, Chemical Reactions, and Conservation of Matter. Select a key idea to see the sub-ideas, assessment items, results from our field testing, student misconceptions, and NGSS statements for that idea.

A pure substance has characteristic properties, such as density, a boiling point, and solubility, all of which are independent of the amount of the substance and can be used to identify it.

Many substances react chemically in predictable ways with other substances to form new substances with different characteristic properties.

When substances interact to form new substances, the atoms that make up the molecules of the original substances rearrange into new molecules.

Whenever substances within a closed system interact with one another, the total mass of the system remains the same.

Whenever atoms interact with each other, regardless of how they are arranged or rearranged, the total mass stays the same.

When substances interact to form new substances, the atoms that make up the molecules of the original substances rearrange into new molecules.
-and-
Whenever atoms interact with each other, regardless of how they are arranged or rearranged, the total mass stays the same.