What is the solubility of silver chromate in parts per million?

Solubility of a given compound is referred to a specific temperature and solvent. This means that you need some data or starting information.

In this case you can use the molar solubility of the silver chromate in water at 25.0 °C.

The molar solubility of silver chormate is 1.10 * 10 ^ -12 M.

This means 1.10 * 10 -12 mol of silver chromate per liter of solution.

Given that the concentration of the solution is so low the density of it is almost the same density of water, i.e. 1g/mL.

Then you have 1.10 - 10^-12 mol of silver chromate per 1000 g of solution

Now convert the moles of silver chromate in grams, using its molar mass.

Silver chromate is Ag2CrO4.

Molar mass of Ag2 CrO4 = 2*108g/mol +52g/mol + 4*16g/mol = 332 g/mol

1.10 * 10^-12 mol * 332 g/mol = 3.652 * 10^ -10 g.

That is the number of grams in 1000 grams of solution, then you need to multiply times 1000 to convert to 1,000,000 grams of solution =

3.652 * 10^-10 * 10^3 grams of Ag2CrO4 / 1,000,000 grams of solution = 3.652 * 10^-7 grams of Ag2CrO4 / 1,000,000 grams of solution =

Remember ppm is parts per million, then it is 3.652 * 10^ -7 ppm

3.652 * 10^-7 ppm