A mole is a unit of measurement used in chemistry. A mole of any element will contain the same amount of particles  Avogandro's number, or 6.02 x 10^23. Using the mole is a consistent method for converting between atoms/molecules and grams of an element. For example, one mole of carbon is exactly the same as one mole of oxygen in terms of particles, but one mole of carbon does not weigh the same as one mole of oxygen.

Pick an element. Determine how much of the element you have in terms of weight.

Divide the weight by its molar mass to determine how many moles your element is.
For example, if you have 18 grams of carbon and know that the molar mass of carbon is 12 grams, divide 18 by 12, which equals 1.5. This is the moles of carbon you have.

Translate the given amount of moles into another element's weight by diving the number of moles by the other element's molar mass.
For example, if you want to determine what 1.5 moles of carbon is equivalent to in oxygen, first convert the moles of carbon into grams of oxygen. Multiple 1.5 moles of carbon by oxygen's molar mass, which is 16. 1.5 X 16 = 24. 24 grams of oxygen is equivalent in weight to 1.5 moles of carbon.
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