How would you solve this?

"Calculate the amount of energy transferred if only 650.50 grams of sulfur trioxide (SO3) gas were produced. (Remember the ∆H = - 396.8 kJ is part of the balanced equation) "

balanced equation: 2 SO2 (g) + O2 (g) ⇌ 2 SO3 (g) ∆H = - 396.8 kJ

1.6*10^3 KJ

Explanation:

We must first calculate the number of moles corresponding to 650.50g of sulphur trioxide.

Number of moles = mass of sulphur trioxide / molar mass of sulphur trioxide

Molar mass of sulphur trioxide = 80.066 g/mol

Given mass of sulphur trioxide = 650.50g

Number of moles = 650.50g / 80.066 g/mol

Number of moles = 8.124 moles of sulphur trioxide

Now from the balanced reaction equation;

Formation of 2 moles of sulphur trioxide evolves 396.8KJ of energy.

Therefore formation of 8.124 moles of sulphur trioxide will evolve;

8.124moles * 396.8 KJ / 2 moles = 1611.8KJ or 1.6*10^3 KJ