what mass of K2SO4 would you measure out to prepare 550 mL of a 0.76 M solution?
7.9
To calculate the mass of K2SO4 required to prepare a 0.76 M solution in 550 mL of water, we need to use the formula:
Mass (g) = concentration (M) x volume (L) x molar mass (g/mol)
First, let's convert the volume from milliliters to liters:
Volume (L) = 550 mL ÷ 1000 = 0.55 L
The molar mass of K2SO4 can be calculated as:
Molar Mass (K2SO4) = (2 x molar mass of K) + molar mass of S + (4 x molar mass of O)
Molar Mass (K2SO4) = (2 x 39.1 g/mol) + 32.1 g/mol + (4 x 16.0 g/mol)
Molar Mass (K2SO4) = 174.3 g/mol
Now we can calculate the mass using the formula mentioned earlier:
Mass (g) = 0.76 M x 0.55 L x 174.3 g/mol
Mass (g) = 69.86 g
So, you would measure out approximately 69.86 grams of K2SO4 to prepare a 0.76 M solution in 550 mL of water.
To find the mass of K2SO4 needed to prepare the solution, you need to know the molarity (M) and volume (V) of the solution. The molarity represents the number of moles of solute (in this case, K2SO4) per liter of solution.
First, we need to calculate the number of moles of K2SO4 required using the formula:
moles = molarity (M) x volume (V)
Given:
Molarity (M) = 0.76 M
Volume (V) = 550 mL = 0.55 L (since 1 L = 1000 mL)
moles = 0.76 M x 0.55 L
moles = 0.418 mol
Now, we can calculate the molar mass of K2SO4 (potassium sulfate) using the periodic table:
K (potassium) = 39.10 g/mol
S (sulfur) = 32.07 g/mol
O (oxygen) = 16.00 g/mol
Molar mass of K2SO4 = (2 x K) + S + (4 x O)
Molar mass of K2SO4 = (2 x 39.10) + 32.07 + (4 x 16.00)
Molar mass of K2SO4 = 174.26 g/mol
Finally, we can find the mass of K2SO4 by multiplying the molar mass by the number of moles:
mass = moles x molar mass
mass = 0.418 mol x 174.26 g/mol
mass ≈ 72.76 g
Therefore, you would need to measure out approximately 72.76 grams of K2SO4 to prepare a 550 mL 0.76 M solution.
M = moles/L
Solve for moles.
moles = grams/molar mass
Solve for grams.