Calculate the molarity of a solution which contains 6.456g of Na2CO3 dissolved in 250.0 ml of solution.
Molarity=mass/formulamass * 1/.250
To calculate the molarity of a solution, you need to know the amount of solute, the volume of the solution, and the molar mass of the solute.
Step 1: Determine the molar mass of Na2CO3.
The molar mass of Na2CO3 can be calculated by adding up the atomic masses of each element in the compound.
Na: 2 x atomic mass of Na = 2 x 22.99 g/mol = 45.98 g/mol
C: 1 x atomic mass of C = 1 x 12.01 g/mol = 12.01 g/mol
O: 3 x atomic mass of O = 3 x 16.00 g/mol = 48.00 g/mol
Therefore, the molar mass of Na2CO3 is 45.98 + 12.01 + 48.00 = 105.99 g/mol.
Step 2: Convert the mass of Na2CO3 to moles.
To convert the mass of Na2CO3 to moles, divide the mass by the molar mass.
Number of moles = mass (g) / molar mass (g/mol)
Number of moles = 6.456 g / 105.99 g/mol
Step 3: Convert the volume of the solution to liters.
The volume is given in milliliters, but molarity is expressed in moles per liter (M). Therefore, you need to convert milliliters to liters.
Volume (L) = volume (mL) / 1000
Volume (L) = 250.0 mL / 1000 = 0.250 L
Step 4: Calculate the molarity.
Molarity (M) = moles of solute / volume of solution (in liters)
Molarity (M) = (6.456 g / 105.99 g/mol) / 0.250 L
Molarity (M) ≈ 0.242 M
Therefore, the molarity of the solution is approximately 0.242 M.