Calculate the molarity of a solution made by dissolving 16.0 grams of Na2CrO4 in enough water to form exactly 555 mL of solution.
mols Na2CrO4 = grams/molar mass
M = mols/L soln
To calculate the molarity of a solution, we need to know the number of moles of solute dissolved in a given volume of solution (in liters).
First, we need to convert the given mass of Na2CrO4 into moles. The molar mass of Na2CrO4 is calculated by summing the atomic masses of its constituent elements:
Molar mass of Na2CrO4 = (2 * Atomic mass of Na) + Atomic mass of Cr + (4 * Atomic mass of O)
= (2 * 22.99 g/mol) + 52.00 g/mol + (4 * 16.00 g/mol)
= 161.97 g/mol
Now we can calculate the number of moles of Na2CrO4:
Number of moles = Given mass / Molar mass
= 16.0 g / 161.97 g/mol
≈ 0.0988 mol
Next, we need to convert the given volume of solution into liters:
Volume of solution = 555 mL = 555 mL * (1 L / 1000 mL)
= 0.555 L
Finally, we can calculate the molarity:
Molarity (M) = Number of moles / Volume of solution
= 0.0988 mol / 0.555 L
≈ 0.178 M
Therefore, the molarity of the solution is approximately 0.178 M.