Air is about 78% nitrogen gas (N2) by mass. The molar mass of nitrogen gas is 28.0 g/mol. A 100.0-g sample of air contains how many moles of nitrogen

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(1) Answers

amodeo

To solve, first convert the 78% to 78 grams (100g of air will contain 78 grams of nitrogen).
Then, you will multiply 78 grams by 1 mol/28 g:
78 x (1/28)
The grams will cancel out, leaving you with 2.79 moles.