Gchem density issue!

[yestomeds]

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This is really sad, but I'm seriously stumped by how to do density conversions.

We're talking about from g/cm^3 to kg/m^3 type stuff.

I've read over TPR on this section, but it was like a paragraph, and I don't get it.

Anyone know of a good quick resource I can use, just to figure this out once and for all?

 

[chemist16]

Just make sure your units cancel out. If you always do that, then there won't be a problem. For instance, g/cm^3 to kg/m^3 means you have to get rid of grams on top and cm^3 on the bottom. So to get rid of those, you have to multiply by the inverse. Just like to get "acceleration" out of F/a = m, you multiply by a. So, g/cm^3 * 1E6cm^3/m^3 * kg/1000g.

 

[JoeCaputo]

For your first several practice problems, expand 1/cm^3 to 1/cm* 1/cm* 1/cm

Now you can clearly see you have three cm's you need to cancel out, so three times, you multiply by 100cm/1m, and you end up with 1/(m*m*m).

After several practices you will get used to it and can shortcut it. For me, I write 1/cm^3 * (100cm/1m)^3.

I'll assume g to Kg is something you are familiar with ( *1kg/1000g)