Question

which jar contains a mixture?
a jar of solid carbon
a jar of carbon dioxide gas
a jar of liquid copper
a jar of copper and water

Explanation:

A mixture contains two or more substances that are not chemically combined. Solid carbon is an element, carbon - dioxide is a compound, and liquid copper is an element. A jar of copper and water has two substances (copper and water) that are not chemically bonded.

Answer:

a jar of copper and water