# Question #d35fd

Jun 28, 2015

That much sodium contains 0.761 moles.

#### Explanation:

To determine the number of moles you have in a certain mass, you need to use molar mass.

Molar mass tells you what the exact mass of 1 mole of a substance is. In your case, the molar mass of sodium is approximately 23.0 g/mol.

This means that 1 mole of sodium will weigh 23.0 g. Since you have less than that, you can expect to have less than one mole.

$17.5 \cancel{\text{g") * "1 mole Na"/(23.0cancel("g")) = color(green)("0.761 moles Na}}$