If you start with 3.500 g of ZnSO4 (Zinc Sulfate) & 7 H2O and heat it for 10+ minutes to remove the water of hydration, what will be the mass of water removed?
Hint: Since you know the number of grams of hydrated salt present you then know the number of moles. Once you know that you can figure out how many moles of water would be released and then its mass.
I'm really at a loss getting this one started. So if anyone knows...
mols ZnSO4.7H2O = 3.500/molar mass(including the 7 mols H2O)
mols H2O = mols ZnSO4.7H2O*7 = ??
g H2O = mols H2O x molar mass H2O = xx grams.
To solve the problem, we need to calculate the molar mass of ZnSO4⋅7H2O, determine the number of moles of ZnSO4⋅7H2O, and then find the number of moles of water released during the heating process.
1. Calculate the molar mass of ZnSO4⋅7H2O:
To calculate the molar mass, you need to sum up the atomic masses of all the atoms in the compound.
Molar mass of Zn = 65.38 g/mol
Molar mass of S = 32.06 g/mol
Molar mass of O = 16.00 g/mol
Molar mass of H = 1.01 g/mol
Therefore, molar mass of ZnSO4⋅7H2O = (65.38 g/mol) + (32.06 g/mol) + 4 × (16.00 g/mol) + 7 × [(1.01 g/mol) + (1.01 g/mol)] = xx g/mol.
2. Calculate the number of moles of ZnSO4⋅7H2O:
To find the number of moles, divide the mass of ZnSO4⋅7H2O by its molar mass.
Number of moles of ZnSO4.7H2O = 3.500 g ÷ xx g/mol = xx mol.
3. Calculate the number of moles of water released:
Since there are 7 moles of water per one mole of ZnSO4⋅7H2O, multiply the number of moles of ZnSO4⋅7H2O by 7 to get the number of moles of water released.
Number of moles of water = xx mol × 7 = xx mol.
4. Calculate the mass of water:
To find the mass of water, multiply the number of moles of water by the molar mass of water.
Mass of water = xx mol × (18.02 g/mol) = xx g.
By following these steps, you will be able to determine the mass of water removed during the heating process. Note that you'll need to substitute the values for the molar mass in step 1 to get the final answer.