Question

calculate the number of moles in the following
1)10g of aluminium sulphate(AL=27,s=32,o=16)
2)1.06 g of sodium sulphate (NA23,s=32,o=32)
3)10g of calcium carbonate (ca=40,o=16,c=12)
4)8g of ammonium nitrate (n=14,h=1,o=16)
5)3g of calcium hydrogen carbonate(ca=40,h=1,o=16)
6)0.18g of water
7)4.9g of sulphur 6 acid

Answer 1

1)First, calculate the molar mass of aluminum sulfate:
Al: 27 g/mol
S: 32 g/mol
O: 16 g/mol x 4 = 64 g/mol

Molar mass of Al2(SO4)3 = 2(27 g/mol) + 3(32 g/mol) + 4(16 g/mol) = 342 g/mol

Number of moles = mass/molar mass
Number of moles = 10g/342 g/mol
Number of moles = 0.0293 mol

2) Molar mass of Na2SO4 = 2(23 g/mol) + 32 g/mol + 4(16 g/mol) = 142 g/mol

Number of moles = mass/molar mass
Number of moles = 1.06 g/142 g/mol
Number of moles = 0.00746 mol

3) Molar mass of CaCO3 = 40 g/mol + 12 g/mol + 3(16 g/mol) = 100 g/mol

Number of moles = mass/molar mass
Number of moles = 10 g/100 g/mol
Number of moles = 0.1 mol

4) Molar mass of NH4NO3 = 14 g/mol + 4(1 g/mol) + 2(16 g/mol) = 80 g/mol

Number of moles = mass/molar mass
Number of moles = 8 g/80 g/mol
Number of moles = 0.1 mol

5) Molar mass of Ca(HCO3)2 = 40 g/mol + 2(1 g/mol) + 2(16 g/mol) + 2(1 g/mol) = 162 g/mol

Number of moles = mass/molar mass
Number of moles = 3 g/162 g/mol
Number of moles = 0.0185 mol

6) Molar mass of H2O = 1 g/mol + 1 g/mol + 16 g/mol = 18 g/mol

Number of moles = mass/molar mass
Number of moles = 0.18 g/18 g/mol
Number of moles = 0.01 mol

7) Molar mass of H2SO4 = 2(1 g/mol) + 32 g/mol + 4(16 g/mol) = 98 g/mol

Number of moles = mass/molar mass
Number of moles = 4.9 g/98 g/mol
Number of moles = 0.05 mol