2h2s (g) + 3o2 (g) → 2h2o (g) + 2so2 (g)

if 3.50 g of h2s are used in the above reaction, what will be the theoretical yield of water in grams?

There are three steps to do: 1) convert grams to moles, 2) convert moles to moles and 3) convert moles to grams

1) let's convert the 3.50 grams of H₂S to moles using the molar mass

molar mass H₂S= (2 x 1.01) + 32.0= 34.02 g/mol

3.50 g (1 mol/ 34.02 g)= 0.103 mol H₂S

2) let's convert moles of H₂S to moles of water using the mole-mole ratio from the balanced equation.

0.103 mol H₂S (2 mol H₂O/ 2 mol H₂S)= 0.103 mol H₂O

3) lastly, let's convert moles of water to grams using the molar mass

molar mass of H₂O= (2 x 1.01) + 16.0= 18.02 g/mol

0.103 mol H₂O (18.02 g/ mol)= 1.85 grams of H₂O

Answerhund's rule;