Find the amount of CuSO4.5H2O needed to prepare 500 mL of 0.25 M solution.
How many moles do you need?
That is M x L = moles.
Then moles CuSO4.5H2O = grams CuSO4.5H2O/molar mass CuSO4.5H2O
You know moles and molar mass, solve for grams.
To find the amount of CuSO4.5H2O needed to prepare a 0.25 M solution in 500 mL, we can follow these steps:
Step 1: Determine the molecular weight of CuSO4.5H2O.
The molecular weight of CuSO4 is 159.61 g/mol, and the molecular weight of H2O is 18.02 g/mol. Therefore, the molecular weight of CuSO4.5H2O is:
(159.61 g/mol) + (5 * 18.02 g/mol) = 249.69 g/mol
Step 2: Calculate the number of moles needed.
The molarity (M) is defined as moles of solute per liter of solution. Since we want to prepare a 500 mL solution, we need to convert 500 mL to liters:
500 mL = 500/1000 L = 0.5 L
The number of moles can be calculated using the formula:
moles = Molarity * Volume(L)
Therefore, the number of moles needed is:
0.25 mol/L * 0.5 L = 0.125 moles
Step 3: Calculate the mass of CuSO4.5H2O needed.
The mass can be calculated using the formula:
mass (g) = moles * molecular weight
Therefore, the mass of CuSO4.5H2O needed is:
0.125 moles * 249.69 g/mol = 31.21 grams
So, you would need 31.21 grams of CuSO4.5H2O to prepare a 500 mL 0.25 M solution.