Question

What is a `"mole"`?

Answer 1

One mole of stuff contains `6.022140857(74)xx10^23` individual items of that stuff.

Explanation:

`6.022140857(74)xx10^23` is often abbreviated as `N_A`; it is simply a number, like 10, or a dozen, or a Bakers' dozen. It has the property that if there are `N_A` `""^12C` atoms, then there is a mass of `12.00` `g` precisely of `""^12C`. So, if have a mole of methane, `CH_4`, I have a mass of `16.00` `g`. In terms of `N_A`, how many (i) carbon atoms, and (ii) hydrogen atoms are present in `16.00` `g` of methane.