# science

posted by on .

I am a mom with limited math and science knowledge. my son is stumped and so am I. The question is "what is the mass of water that covers 12cm3 (that's 3rd power). I haven't a clue of the formula and neither does my son.

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It has a mass of 12 grams. I can elaborate if necessary.

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mass = volume x density.
The 12 cm^3 stands for 12 cubic centimeters (a volume), usually written either as 12 cm3 or as 12 cc or 12 c.c. (but the periods USUALLY are not written). Water has a density of approximately 1.0 gram/cc at temperatures around room T (it can be looked up in tables to 6 places but I assume this is pretty basic stuff so 1.0 is ok instead of writing 0.99997 g/cc). So we substitute 12 cc for the volume and 1.0 g/cc for the volume like this.
mass = volume x density.
mass = 12 cc x 1.0 g/cc = 12 g.
Note that 12 x 1 = 12 and the units are
cc x (g/cc) so the cc unit cancels to leave the mass unit of grams.
I hope this helps but feel free to follow up. By the way, to make things a little more comfortable for people who don't usually think in terms of the metric system, one U. S. teaspoon is almost 5 cc and a U. S. 5-cent piece weighs about 5 grams.

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thank you so much. I hate not having the answers but I didn't have much math and no science since 7th grade myself and kids today are learning more than I ever did.

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I can sympathize. Many of the questions on this board from high school students covers material in chemistry that I didn't have until I was studying for my Ph. D. And I get questions that stump me, too.