# Stuck on mass, volume problems

1. Jun 15, 2004

### terpsgirl

What is the mass of a 10.0 cm cubed cube of copper?
i know that (g/cm cubed)= copper = 8.96 but I'm not sure how to tackle this problem.

also....
If I have 51.5 g of a 50.0 cm cubed volume of one of these substances, which would it be?
Alumininum 2.70 mass density, Copper 8.96, Iron 7.87, Lead 11.4, Water 1.00, Seawater 1.03, Mercury 13.6, Gasoline 0.680....How do I determine which one it is?

A cubic tank holds 1,000.0 kg of water. What are the dimensions of the tank in meters? Whats the reasoning?

Thanks so much!

2. Jun 16, 2004

### BobG

For the first two, the units of measure should give you a pretty good clue.

Mass is measured in grams and that's what you want. You know the density (g/cm^3) and you know the volume (cm^3). If you multiply the density by the volume, the cm^3 will cancel out and leave you with grams.

Same principle for the second, except you know different variables. Set your equation up so you your answer is in the right format for density. Match your density to the choices.

For the third, you have to know how your units of measure are defined. 1 gram is equal to the mass of 1 cm^3 of water. 1000 g (1 kg) is equal to (1000 cm)^3, or (10m)^3. The only challenge here is remembering to multiply your units of measure before you cube them.