What is the mole (mol)?
The mole is the SI unit for “amount of a substance” and is a unit quantity which refers to how much of an element or compound is present.
We have used other words to represent an understood amount, such as “a couple” meaning 2 or “dozen” meaning 12. Consider the same for the mole. A mole can represent how much or amount of a substance.
Moles and Mass
1 mole of an element is 1 unit of that element:
- 1 mole of carbon is the same as saying 1 unit of carbon or 1 C
- 1 mole of carbon is equivalent to the atomic mass of carbon
- 1 mole of carbon = 12 g of carbon
1 mole of a compound is equivalent to the formula weight of the compound:
- 1 mole of glucose is the same as saying 1 unit of glucose or 1 C6H12O6.
- 1 mole of a compound is equivalent to the formula weight of the compound
- 1 mole of glucose = 180 grams
IMPORTANT NOTE: These equivalencies are conversion factors! You can use dimensional analysis to convert one unit to another like any other simple unit conversion.
Recall the set up of dimensional analysis such that given units are positioned to cancel out!
Let’s try some examples:
1. How many moles are in 144 grams of glucose, C6H12O6?
2. How many grams of NaOH are present in 3.45 moles of NaOH? [Ans: 138]