What sample is a pure substance? a. a test tube of zinc oxide.
b. a container of zinc and oxygen.
c. a flask of pond water.
d. a jar of soil.

The correct answer is A. A test tube of zinc oxide. Zinc oxide is a compound which is a pure substance composed of two or more elements. They can only be separated or broken down into its individual elements or smaller compounds by chemical means. Therefore, the answer is a test tube of zinc oxide.

Ithe undersigned only for use your own email and delete any and copies and of the itself and to be there is a good timewhat does a decrease in temperature indicate about the molecules in a sample of liquid water? decreased chemical energy of the moleculesdecreased kinetic energy of the moleculesincreased chemical energy of the moleculesincreased kinetic energy of the moleculeshow does a sample of helium at 15 â°c compare to a sample of helium at 215 k? the helium at 15 â°c has a higher average kinetic energy than the sample at 215 k.the helium at 15 â°c has lower nuclear energy than the sample at 215 k.the helium at 15 â°c has slower-moving atoms than the sample at 215 k.the helium at 15 â°c has smaller atoms than the sample at 215 k.