A technician mixes a solution containing silver nitrate with a solution containing sodium chromate. 2.89 g of precipitate is produced (assume silver chromate). Calculate the mass of silver nitrate present in the first solution. Make sure you have the correct number of significant digits and units.

Answer 1

You really don't know from the way the problem is stated; however, I assume the problem means "if the exact amount of reagents are mixed to produce the 2.89 g Ag2C4O4 and neither reagent is left".

2AgNO3 + Na2CrO4 ==> Ag2CrO4 + 2NaNO3.

mols Ag2CrO4 = grams/molar mass = ?
Using the coefficients in the balanced equation, convert mols Ag2CrO4 to mols AgNO3.
Then mols = grams/molar mass. You know molar mass and mols, solve for grams.