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

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.