Question

Question #2b5ce

Answer 1

`6.0 * 10^(23)`

Explanation:

The thing to remember about an element's molar mass, which you'll find listed in the Periodic Table, is that it tells you the mass of `6.022 * 10^(23)` atoms of that element.

This is the case because the molar mass of an element represents the mass of exactly `1` mole of that element. And since Avogadro's constant tells you that

`color(blue)(ul(color(black)("1 mole" = 6.022 * 10^(23)color(white)(.)"particles")))`

you can say that the molar mass of an element tells you the mass of `6.022 * 10^(23)` atoms of that element.

Now, the Periodic Table tells you that carbon--diamond is simply an allotrope of carbon, i.e. a form that carbon can take--has a molar mass of `"12.011 g mol"^(-1)`.

This means that `1` mole of carbon has a mass of `"12.011 g"`. In other words, `6.022 * 10^(23)` atoms of carbon, the equivalent of `1` mole of carbon, have a mass of `"12.011 g"`.

This means that `"12 g"` of carbon will contain

`12 color(red)(cancel(color(black)("g"))) * (6.022 * 10^(23)color(white)(.)"atoms of C")/(12.011color(red)(cancel(color(black)("g")))) = color(darkgreen)(ul(color(black)(6.0 * 10^(23)color(white)(.)"atoms of C")))`

The answer is rounded to two sig figs, the number of sig figs you have for the mass of carbon.