Calculate the mass of magnesium that can be burned in 33.6 liters of oxygen.

Given:
V (O2) = 33.6 l
Find: m (Mg)

Decision:
1 way
2 Mg + O2 = 2 MgO
1) n (O2) = 33.6 / 22.4 = 1.5 mol
2) n (Mg) / n (O2) = 2/1 (according to the equation) -> n (Mg) = 2n (O2) = 2 * 1.5 = 3 mol
3) m (Mg) = 3 mol * 24g / mol = 72g.

Answer: m (Mg) = 72g.

2 way
1) by condition: x g V l
2 Mg + O2 = 2 MgO
according to the equation: n 2 n 1
M 24 Vm 22.4
m 48 V 22.4

2) make up and solve the proportion:
m (Mg) = V (O2) by the condition * m (Mg) by the equation / V (O2) by the equation;
m (Mg) = 33.6 * 48 / 22.4 = 72g.
Answer: 72g.