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

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To calculate the molarity (M) of a solution, you need to know the moles of the solute and the volume of the solution.

Step 1: Calculate the moles of Na2CrO4.
To calculate the number of moles, you need to know the molar mass of Na2CrO4. The molar mass can be calculated by adding up the atomic masses of all the elements in the compound.

The atomic masses of the elements are:
Na (sodium) = 22.99 g/mol
Cr (chromium) = 52.00 g/mol
O (oxygen) = 16.00 g/mol

The molar mass of Na2CrO4 can be calculated as follows:

(2 * Na) + Cr + (4 * O) = (2 * 22.99 g/mol) + 52.00 g/mol + (4 * 16.00 g/mol) = 105.99 g/mol

Now, you can calculate the moles of Na2CrO4 by dividing the given mass by the molar mass:

moles = mass / molar mass = 12.5 g / 105.99 g/mol

Step 2: Calculate the volume of the solution in liters.
The given volume is 550 mL, but molarity is typically expressed in liters. So, convert the volume from milliliters to liters by dividing by 1000:

volume = 550 mL / 1000 = 0.55 L

Step 3: Calculate the molarity.
The molarity (M) is defined as moles of solute per liter of solution. Therefore, divide the moles of Na2CrO4 calculated in step 1 by the volume of the solution calculated in step 2:

Molarity = moles / volume = moles / 0.55 L

Now, plug in the calculated values to find the molarity.