.......moles..........?

Question

..........Moles........?

Mass of CuSO4 xH2O:

5.00g

Mass of CuSO4:

3.196g

Mass of H2O:

1.804g

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Moles of CuSO4?

Moles of H2O:

Moles of H2O for every mole of CuSO4?

Chemical formula of CuSO4 XH2O?

Answer 1

You can use the molar mass of a substance of known mass to find the moles of that substance.

1. mass x molar mass = moles

g x mol/g = mol

or

2. moles x molar mass = mass

mol x g / mol = g

since you know the mass and want to find the moles we'll use the first equation.

procedure: compute molar mass of substance and then multiply the mass of the substance by the inverse of the molar mass to find the moles of the substance.

molar mass CuSO4: 63.546 + 32.065 + 4(15.999) = 159.607 g/mol

moles of CuSO4:

(3.196 g CuSO4)(mol CuSO4/159.607 g CuSO4) = 0.020024184 mol CuSO4

molar mass of H2O: 2(1.00794) + 15.999 = 18.01488 g/mol

moles of H2O:

(1.840 g H2O)(mol H2O/ 18.01488 g H2O) = 0.102137788 mol H2O

moles of H2O for every mole of CuSO4:

moles of H2O/moles of CuSO4 = 0.102137788mol/0.020024184mol = 5.100721607 = 5

CuSO4 * 5H2O

Answer 2

1.)moles of H2O = given mass by GAM[gram atomic mass = 18g]                 1.804/18 = 0.1moles

2.) moles of CuSO4 = 3.196/159[63+32+64]

                              =0.02 moles

4.) for calculating the value of x, use empirical formula way.