0.499g of cuso4.XH2O when heated to constant weight gave a residue of 0.36g. what is the value of X
0.499 g - 0.36 g = 0.139 g = mass H2O expelled.
mols H2O = g/molar mass = 0.139/18 = 0.00772
mols CuSO4 = 0.36/160 = 0.00225
0.00772/0.00225 = 3.5 for X.
I suspect a typo in your post. Check it. X should be 5.0 or very close to that.
To find the value of X in CuSO4·XH2O, we need to calculate the difference in mass before and after heating.
Step 1: Calculate the mass of water lost during heating:
Initial mass - Final mass = Mass of water lost
0.499 g - 0.36 g = 0.139 g
Step 2: Determine the number of moles of water lost:
We can use the molar mass of water (H2O) to convert the mass of water lost into moles. The molar mass of water is 18.02 g/mol.
Number of moles = Mass of water lost / molar mass of water
= 0.139 g / 18.02 g/mol
≈ 0.0077 mol
Step 3: Determine the mole ratio between CuSO4 and H2O:
From the formula CuSO4·XH2O, we can see that there should be one mole of CuSO4 for every X moles of H2O.
So, the mole ratio is 1: X
Step 4: Convert moles of water lost to moles of X:
Since the mole ratio is 1: X, we can write the following equation:
0.0077 mol H2O × (1 mol X / X mol H2O) = 0.0077 / X mol
Step 5: Equate moles of X to the molar mass of X:
The molar mass of X is equal to the mass of X in grams per mole.
0.0077 / X mol × molar mass of X = Mass of X
Step 6: Substitute the given data to solve for X:
Given that the mass of X is 0.36 g, we can set up the equation:
0.0077 / X mol × molar mass of X = 0.36 g
Now, you can solve this equation to find the value of X.
To determine the value of X in the compound CuSO4·XH2O, we need to calculate the molar mass of CuSO4·XH2O and compare it with the given information.
Step 1: Calculate the molar mass of CuSO4.
- Copper (Cu) has a molar mass of 63.55 g/mol.
- Sulfur (S) has a molar mass of 32.07 g/mol.
- Oxygen (O) has a molar mass of 16.00 g/mol (there are 4 oxygen atoms in CuSO4).
Therefore, the molar mass of CuSO4 is:
63.55 g/mol + (32.07 g/mol + 4 × 16.00 g/mol) = 159.61 g/mol.
Step 2: Calculate the molar mass of H2O.
- Hydrogen (H) has a molar mass of 1.01 g/mol (there are 2 hydrogen atoms in H2O).
- Oxygen (O) has a molar mass of 16.00 g/mol.
Therefore, the molar mass of H2O is:
2 × 1.01 g/mol + 1 × 16.00 g/mol = 18.02 g/mol.
Step 3: Calculate the molar mass of CuSO4·XH2O.
The molar mass of CuSO4·XH2O is the sum of the molar masses of CuSO4 and XH2O:
159.61 g/mol + X × 18.02 g/mol.
Step 4: Calculate the mass of CuSO4.
Given that 0.499 g of CuSO4·XH2O produces a residue of 0.36 g, we can subtract the mass of the residue from the initial mass to find the mass of CuSO4:
0.499 g - 0.36 g = 0.139 g.
Step 5: Set up a proportion to find the value of X.
Since the molar mass of CuSO4·XH2O is equal to the mass of CuSO4, we have the equation:
159.61 g/mol + X × 18.02 g/mol = 0.139 g.
Solving for X:
X × 18.02 g/mol = 0.139 g - 159.61 g/mol
X × 18.02 g/mol = -159.471 g/mol
X = -159.471 g/mol ÷ 18.02 g/mol
X ≈ -8.85
Based on the calculation, X has a negative value, which is not meaningful. Thus, it is likely that there was an error in the experimental data or the given information.