The mole (abbreviated molmol) is a counting unit used to simplify calculations that would otherwise involve very large numbers (see previous exercise: Of Mass and Moles).

One mole of a substance contains 6.02210236.0221023 formula units, as shown in the following unit factor:

6.0221023formulaunits1molsubstance6.0221023formulaunits1molsubstance

The term formula unit is a generic phrase that can mean a molecule, atom, ion, or whatever is represented by the chemical formula. For example, a mole of HeHe contains 6.02210236.0221023 helium atoms. A mole of N2N2 contains 6.02210236.0221023 diatomic N2N2 molecules.

Note that in one mole of N2N2 molecules, there are 2 moles of nitrogen atoms because each diatomic molecule of nitrogen (N2N2) contains two nitrogen atoms (NN).

This is particularly important for solving this problem.

The fuel used in many disposable lighters is liquid butane, C4H10 . Butane has a molecular weight of 58.1 grams in one mole. How many carbon atoms are in 3.00 g of butane? Express the number of atoms to three significant figures.