How many grams of oxygen reacted if 1320 kJ of heat was released?

Given:
Q1 = 1320 kJ

To find:
m (O2) -?

Decision:
1) Write down the equation of the thermochemical reaction:
S + O2 => SO2 + 440 kJ;
2) Make up the proportion and calculate the amount of substance O2:
440 kJ – 1 mol O2;
1320 kJ – (x) mol O2;
x = n (O2) = 1320 * 1/440 = 3 mol;
3) Using the periodic system of D.I.Mendeleev, calculate the molar mass of O2:
M (O2) = Mr (O2) = Ar (O) * N (O) = 16 * 2 = 32 g / mol;
4) Calculate the mass of O2:
m (O2) = n (O2) * M (O2) = 3 * 32 = 96 g.

Answer: O2 mass is 96 g