?

AP® Chemistry

Free Version

Upgrade subject to access all content

Easy

Change in Mass

APCHEM-X8OG4T

A 0.543 g sample of copper oxide is heated in a properly prepared crucible. Its final mass after heating is 0.519 g.

Which of the following is the BEST explanation for this change in mass?

A

The crucible was not completely cooled when​ weighed.

B

The sample was improperly stored while cooling, causing moisture to be absorbed by the copper oxide.​

C

The copper oxide decomposed and oxygen gas was produced.

D

Black soot appeared on the crucible while heating, changing the masses obtained in the lab.