Question

How many atoms or molecules are present in 1.0 mol of Au? How am I able to find the answer?

Answer 1

You use the fact that 1 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, 1 mole of gold will have exactly `6.022 * 10^(23)` atoms of gold.

`1.0cancel("mole") * (6.022 * 10^(23)"atoms")/(1cancel("mole")) = 6.022 * 10^(23)"atoms of Au"`

If round the answer to two sig figs, the number of sig figs in 1.0, you'll get

`"1.0 mole Au" = color(green)(6.0 * 10^(23)"atoms Au")`

Here's a video which illustrates how to solve a problem converting from

video from: Noel Pauller

And here is an advanced example...

video from: Noel Pauller