Question #98dd6

1 Answer
Stefan V.
Nov 25, 2015

6 * 10^(23)

Explanation:

You know that one mole of any substance contains exactly 6.022 * 10^(23) atoms or molecules of that substance - this is known as Avogadro's number.

In your case, you're dealing with a millimole, which represents the 1/1000"th" part of a mole.

So, if you need 10^3 millimoles to make one mole, it follows that you'd need 10^3 times more molecules of carbon dioxide, "CO"_2, to get 6.022 * 10^(23) molecules of carbon dioxide.

1color(red)(cancel(color(black)("mmole"))) * (1color(red)(cancel(color(black)("mole"))))/(10^3color(red)(cancel(color(black)("mmoles")))) * (6.022 * 10^(23)"molecules CO"_2)/(1color(red)(cancel(color(black)("mole")))) = 6.022 * 10^(23)"molecules CO"_2

You need to round this off to one sig fig, the number of sig figs you have for the number of millimoles of "CO"_2.

"no. of molecules of CO"_2 = color(green)(6 * 10^(23))

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