Chemistry Question

Question

A sheet of aluminum foil has a length width and height of 8.2 cm 9.93 cm and 0.00150 cm respectively aluminum has a density of 2.70 g/cm³ . What is the mass in grams of the foil?

Answer 1

Hi Sam,

If you look at the end of the question it's asking for the mass. When we dissect the rest of the problem we see we are given the 3D dimensions of the aluminum and the density of aluminum.

We know that density=mass/volume. If we rearrange this equation by multiplying both sides by volume we get density*volume=mass.

So how do we find volume? Use the length, width, and height. If we multiply them together we get

8.2 cm*9.93 cm*0.00150 cm= 0.12 cm³ (this is our volume). Make sure all of these measurements are in the same units before multiplying.

We can then use our volume of 0.12 cm^3 and density of 2.70 g/cm^3 to find our mass.

The mass=0.12 cm³*2.70 g/cm³ which gives us 0.32 g.

You can double check your work by tracking your units. You can see that the cm³ cancels out and leaves us with grams. Hope this helps!

Answer 2

Hello, Sam,

This appears to be a straightforward calculation of total Al volume (cm^3) multiplied by it's density (g/cm^3).

The volume is 8.2 * 9.93 * 0.0015 = 0.122139 cm^3, which needs to be set to only 2 significant digits (the 8.2 value). = 0.12 cm^3

When the volume is multiplied by the density of Al (2.70g/cm^3), the volumes cancel (cm^3) and we are left with just grams. That yields a mass of 0.32 grams.

I hope that helps,

Bob