Final answer:
To find the molarity of a Na2CrO4 solution, divide the number of moles of Na2CrO4 by the volume of the solution in liters. The molarity is calculated to be 0.1077 M.
Step-by-step explanation:
The question asks to calculate the molarity of a solution made by dissolving sodium chromate (Na2CrO4) in water. To find the molarity, the number of moles of Na2CrO4 needs to be determined first. After that, you divide the number of moles by the volume of the solution in liters.
First, the molar mass of Na2CrO4 is calculated using the periodic table:
Na = 22.99 g/mol × 2 = 45.98 g/mol
Cr = 51.99 g/mol
O = 16.00 g/mol × 4 = 64.00 g/mol
Total = 161.97 g/mol
Next, the moles of Na2CrO4 are found:
12.9 g ÷ 161.97 g/mol = 0.0797 moles
Then, convert the volume of the solution from milliliters to liters:
740 ml = 0.740 L
Finally, calculate the molarity:
0.0797 moles ÷ 0.740 L = 0.1077 M (Molarity = moles/volume)
Therefore, the molarity of the Na2CrO4 solution is 0.1077 M.