Calculate the molarity of the following.
45 grams of Na2SO4 dissolved to make 500 ml of solution
30 grams of C4H8O4 dissolved to make 450 ml of solution
To calculate the molarity of a solution, we first need to find the number of moles of the solute and then divide it by the volume of the solution in liters.
1. For the first solution (Na2SO4):
- Find the number of moles of Na2SO4 by dividing the given mass by its molar mass. The molar mass of Na2SO4 is calculated as follows:
Molar mass of Na = 22.99 g/mol
Molar mass of S = 32.07 g/mol
Molar mass of O = 16.00 g/mol
Total molar mass of Na2SO4 = (2 * Na) + S + (4 * O) = 22.99 * 2 + 32.07 + 16.00 * 4 = 142.04 g/mol
Number of moles of Na2SO4 = mass of Na2SO4 / molar mass of Na2SO4
= 45 g / 142.04 g/mol
≈ 0.316 moles of Na2SO4
- Convert the given volume from milliliters to liters:
500 ml = 500/1000 L = 0.5 L
- Finally, calculate the molarity of the Na2SO4 solution by dividing the number of moles by the volume in liters:
Molarity (M) = moles of solute / volume of solution (in liters)
= 0.316 moles / 0.5 L
≈ 0.632 M
Therefore, the molarity of the solution containing 45 grams of Na2SO4 dissolved in 500 ml of water is approximately 0.632 M.
2. For the second solution (C4H8O4):
- Following a similar process, we find the number of moles of C4H8O4:
Molar mass of C = 12.01 g/mol
Molar mass of H = 1.01 g/mol
Molar mass of O = 16.00 g/mol
Total molar mass of C4H8O4 = (4 * C) + (8 * H) + (4 * O)
= 4 * 12.01 + 8 * 1.01 + 4 * 16.00
≈ 144.12 g/mol
Number of moles of C4H8O4 = mass of C4H8O4 / molar mass of C4H8O4
= 30 g / 144.12 g/mol
≈ 0.208 moles of C4H8O4
- Convert the given volume from milliliters to liters:
450 ml = 450/1000 L = 0.45 L
- Calculate the molarity of the C4H8O4 solution by dividing the number of moles by the volume in liters:
Molarity (M) = moles of solute / volume of solution (in liters)
= 0.208 moles / 0.45 L
≈ 0.462 M
Therefore, the molarity of the solution containing 30 grams of C4H8O4 dissolved in 450 ml of water is approximately 0.462 M.
To calculate the molarity, we need to use the formula:
Molarity (M) = moles of solute / volume of solution in liters
First, we need to calculate the moles of each solute.
For Na2SO4:
The molar mass of Na2SO4 is calculated as:
2(22.99 g/mol) + 32.07 g/mol + 4(16.00 g/mol) = 142.04 g/mol
To calculate the moles, we divide the given mass by the molar mass:
moles = mass / molar mass = 45 g / 142.04 g/mol = 0.3164 mol
For C4H8O4:
The molar mass of C4H8O4 is calculated as:
4(12.01 g/mol) + 8(1.008 g/mol) + 4(16.00 g/mol) = 144.14 g/mol
To calculate the moles, we divide the given mass by the molar mass:
moles = mass / molar mass = 30 g / 144.14 g/mol = 0.208 mol
Now, let's calculate the molarity for each solution:
For Na2SO4:
Molarity (M) = moles of solute / volume of solution in liters
Molarity = 0.3164 mol / 0.5 L = 0.6328 M
For C4H8O4:
Molarity (M) = moles of solute / volume of solution in liters
Molarity = 0.208 mol / 0.45 L = 0.4622 M
Therefore, the molarity of the Na2SO4 solution is 0.6328 M, and the molarity of the C4H8O4 solution is 0.4622 M.