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Avogadro's Number

A gas cylinder contains exactly 15 moles of oxygen gas (O2). How many molecules of oxygen are in the cylinder?

Verified Answer :

using AVOs numberĀ 
moles -> moleculesĀ 
multiply moles # by AVOs #
15 x (6.022x10^23=

Avogadro's number of 6.02E23 is defined as the number of molecules in a mole. (For a compound, it would be the number of formula units in a mole.) Therefore, if we are given 15 moles of oxygen gas, multiplying by 6.02E23 gives the total number of molecules in the gas cylinder. This is equivalent to 9.03E24 molecules of oxygen gas contained in the cylinder.