In a chemical analysis, a technician mixes silver nitrate solution with excess sodium chromate solution to produce 2.89g of precipitate. What mass of silver nitrate was present in the original solution?

A chromium(III) chloride solution is analyzed by having a sample of the solution react with a 50.0g piece of zinc metal. Adter the reaction, 38.5g of zinc remained. Calculate the mass of chromium (III) chloride that was present in the sample tested?

Do you have tips on making these simpler and on solving them? I go blank I don't understand them at all.....anything you can tell me would be great, thank you so much.