If a 8.6195 g of a mixture which contains (20.0 % of CuSO4.XH2O and 80.0 % of sand) was heated in

a crucible then cooled in the desiccator the mass obtained was 7.9976 g.
a- Find X the number of water of hydration in the Hydrate (CuSO4.XH2O)
(MM of CuSO4 = 159.5 g/mol and MM of H2O = 18.00 g/mol).

please help me ,becauce i have final exam tomorrow

8.6195 = g CuSO4.xH2O + sand

-7.9976 = g CuSO4 - H2O + sand
----------
0.6219 = g H2O lost

8.6195 = g CuSO4.xH2O + sand
x 0.20 CuSO.xH2O

= 1.7239 = g CuSO4.xH2O
-0.6219 = mass xH2O
--------------
= 1.102 = g CuSO4

mols CuSO4 = g/molar mass = 1.102/159.5 = estimated 0.0069
mols H2O = g/molar mass = 0.6219/18 = estimated 0.0345
Then find the ratio for mols H2O per 1 mol CuSO4. That's 0.0345/0.0069 = 5.0
Then find ratio of

To find the number of water molecules of hydration (X) in the hydrate (CuSO4.XH2O), we can follow these steps:

Step 1: Calculate the mass of CuSO4 in the mixture:
To find the mass of CuSO4 in the mixture, we first need to determine the mass of the entire mixture by subtracting the mass obtained after heating and cooling from the initial mass:
Mass of mixture = Initial mass - Mass obtained after heating and cooling
Mass of mixture = 8.6195 g - 7.9976 g = 0.6219 g

Now, calculate the mass of CuSO4 in the mixture:
Mass of CuSO4 = Mass of mixture * Percentage of CuSO4
Mass of CuSO4 = 0.6219 g * (20.0% / 100) = 0.1244 g

Step 2: Calculate the moles of CuSO4:
To calculate the moles of CuSO4, we need to use its molar mass, which is given as 159.5 g/mol.
Moles of CuSO4 = Mass of CuSO4 / Molar mass of CuSO4
Moles of CuSO4 = 0.1244 g / 159.5 g/mol = 0.000778 mol

Step 3: Calculate the moles of H2O:
Since we know that CuSO4.XH2O is a hydrate, the molar ratio between CuSO4 and H2O is 1: X. Therefore, the moles of H2O will be the same as the moles of CuSO4.

Moles of H2O = Moles of CuSO4 = 0.000778 mol

Step 4: Calculate the mass of H2O:
To calculate the mass of H2O, we need to use its molar mass, which is given as 18.00 g/mol.
Mass of H2O = Moles of H2O * Molar mass of H2O
Mass of H2O = 0.000778 mol * 18.00 g/mol = 0.0140 g

Step 5: Calculate the value of X:
The mass of water (H2O) is equal to X times the molar mass of water.
Mass of H2O = X * Molar mass of H2O
0.0140 g = X * 18.00 g/mol

Cross-multiplying the equation:
X = (0.0140 g) / (18.00 g/mol)
X ≈ 0.00078 mol

Therefore, the number of water of hydration in the hydrate (CuSO4.XH2O) is approximately 0.00078.