JSS 2: Molar mass

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Molar mass is the mass per unit mole of a given chemical substance.
The S.I.unit of molar mass is g/mol 
Examples:
Calculate the molar mass of the following:
1. Water (H2O)
2. Table salt (NaCl)
3. Calcium oxide (CaO)
4. Calcium carbonate (CaCO3)  
[H=1, O=16, Na=23, Cl=35.5, C=12, Ca=40]
Solution: 
1. H2O= 2(1) + 16 
            = 18g/mol 

2. NaCl= 23 +35.5 
             =58.5g/mol 

3. CaO= 40+16 
            =56g/mol 

4. CaCO3 = 40+12+3(16) 
                  =52+48 
                  =100g/mol

                   NUMBER OF ATOMS
Calculate the number of atoms in each of the following:
1. H2O
2. Three moles of H2O
3. NaOH 
4. Two moles of NaOH 
5. H2SO4
               Solution:
1. H2O   = 2+1= 3 atoms
2. 3H2O = 3(2+1)=3(3)= 9 atoms
3. NaOH = 1+1+1= 3 atoms
4. 2NaOH = 2 (3)= 6 atoms
5. H2SO4 = 2+1+4(1) = 3 + 4=7 atoms 
                      Assignment 
A. Calculate the molar mass of the following compounds:
1. Sodium nitrate (NaNO3)
2. Aluminum oxide (Al2O3)
3. Barium chloride (BaCl2)
4. Potassium hydroxide (KOH)
5. Hydrogen chloride (HCl)
6. Potassium sulphate (K2SO4)
7. Calcium carbonate (CaCO3)
8. Sodium oxide (NaO)
9. Hydrogen peroxide (H2O2)
10. Hydrogen carbonate( H2CO3)
[Na=23, N=14, O=16, Al=27, Ba=137, Cl=35.5, K= 39, S=32, Ca=40, C=12, H=1]

B. Find the number of atoms in each of the following :
1. Two moles of Sodium nitrate (NaNO3)
2. Three moles of Aluminum oxide (Al2O3)
3. One mole of Barium chloride (BaCl2)
4. Five moles of Potassium hydroxide (KOH)
5. Three moles of Hydrogen chloride (HCl)
6. Six moles of Potassium sulphate (K2SO4)
7. One mole of Calcium carbonate (CaCO3)
8. Four moles of Sodium oxide (NaO)
9. Five moles of Hydrogen peroxide (H2O2)
10. Ten moles of Hydrogen carbonate( H2CO3)

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