Converting Between Moles and Grams

To convert between moles and grams we will use the factor label system, which was discussed in the first unit of this text.

Remember that the molar mass of something is the number of grams in a mole. That means, for instance, that 1 mole of carbon weighs 12.011 g and that 12.011 g of carbon is one mole. Of course this idea works for molecules as well, so 1 mole of water weighs 18.0153 g and 18.0153 g of water is a mole.

Let's try a few problems: 

What is the mass (in grams) of 3.87 moles of sodium hydroxide? 
We'll solve this problem the way we solved other factor label problems, we start with the known and then put in a fraction equal to one, using the units in the problem to tell us which way to arrange the fraction.

A balloon contains 65.3 g of carbon dioxide. How many moles of CO2 are in the balloon?