B. The forwards and backwards motions are equal
They both are actually the same thing
A. Molar Mass
Explanation:
Gram molecular mass is the mass in grams of one mole of a molecular substance. Gram molecular mass is the same as molar mass.
Density is mass over volume. If you put it into a formula it would look like this:
Based on the problem given, you can see that the mass of the aluminum block is 82.0 g and the volume is 12.8 cm3. Just put that into your equation and solve for it:
The answer is then letter C.