If 0. 200 moles of agno₃ react with 0. 155 moles of h₂so₄ according to this unbalanced equation below, what is the mass in grams of ag₂so₄ that could be formed? agno₃(aq) + h₂so₄ (aq) → ag₂so₄ (s) + hno₃ (aq)

Balance the reaction.

a AgNO₃ (aq) + b H₂SO₄ (aq)   →   c Ag₂SO₄ (s) + d HNO₃ (aq)

Count the atoms of each element on either side:

• Ag : a = 2c

• N : a = d

• O : 3a + 4b = 4c + 3d

• H : 2b = d

• S : b = c

Let c = 1. Then a = d = 2 and b = 1 and all the counts are consistent. So the balanced reaction is

2 AgNO₃ (aq) + H₂SO₄ (aq)   →   Ag₂SO₄ (s) + 2 HNO₃ (aq)

which is to say 1 mol H₂SO₄ is needed for every 2 mol AgNO₃ to produce 1 mol Ag₂SO₄.

We start with 0.200 mol AgNO₃, so we can use up at most 0.100 mol H₂SO₄ (and leave an excess 0.055 mol). These react together to produce 0.100 mol Ag₂SO₄

Ag₂SO₄ has a molar mass of about 311.79 g/mol, so this reaction will produce a mass of

(0.100 mol) (311.79 g/mol) ≈ 31.2 g Ag₂SO₄