Question

How many grams of Ca metal are needed to react with 15.3 liters of N2 gas at STP?
3 Ca(s) + N2(g) → Ca3N2(s)

Answer 1

Solution:

At standard temperature and pressure, 1 mole of any gas occupies 22.4 L.

According to the reaction equation for 1 mol of N₂ are needs 3 moles of Ca.

molar mass of Ca 40.078 gram/mol.

And then, calculate the mass of Ca

m Ca = $(15.3 L)/(22.4 L/mol)×(3 mol)/(1 mol)×40.078 g/mol$ = 82.12 g

Answer: are needed to react 82.12 grams of Ca.