Calculate the molarity of a solution made by dissolving 12.5 grams of Na2CrO4 in enough water to form exactly 550 mL of solution.

To calculate the molarity of a solution, you need to know the number of moles of the solute (the substance being dissolved) and the volume of the solution in liters.

First, let's calculate the number of moles of Na2CrO4:

Given mass of Na2CrO4 = 12.5 grams

The molar mass of Na2CrO4 can be found by adding the atomic masses of its constituent elements.

Na: 2 atoms x atomic mass of Na = 2 x 22.99 g/mol
Cr: 1 atom x atomic mass of Cr = 1 x 52.00 g/mol
O: 4 atoms x atomic mass of O = 4 x 16.00 g/mol

Total molar mass of Na2CrO4 = (2 x 22.99) + 52.00 + (4 x 16.00) g/mol

Now, divide the given mass of Na2CrO4 by its molar mass to find the number of moles:

Number of moles of Na2CrO4 = 12.5 g / (2 x 22.99 + 52.00 + 4 x 16.00) g/mol

Next, convert the volume of the solution from milliliters to liters:

Volume of solution = 550 mL = 550 mL x (1 L / 1000 mL)

Now that we have the number of moles of Na2CrO4 and the volume of the solution in liters, we can calculate the molarity:

Molarity (M) = Number of moles of solute / Volume of solution (in liters)

Substitute the values we calculated into the formula:

Molarity (M) = Number of moles of Na2CrO4 / Volume of solution

Now, plug in the values to get the answer.