Question

Q.6. Verify by calculating that:

(a)5 moles of CO2 has higher mass than 5 moles of H20

(b)120 g of calcium and 120 g magnesium elements have a mole ratio of 3: 5.

Answer 1

(a) CO2 has molar mass               = 44g mol–1 

5 moles of CO2 have molar mass = 44 × 5 

                                                     = 220 g 

H2O has molar mass                   = 18 g mol–1 

5 moles of H2O have mass         = 18 × 5 g 

                                                   = 90 g 

(b) Number of moles in 240g Ca metal  = 240/ 40 = 6 

Number of moles in 240g of Mg metal  = 240 /24 = 10 

Ratio 6:10 

         3: 5

Answer 2

c=12
0=16
h=1

co2=12+32=44
h2o=2+16=18
5 mole co2=44*5=220
5 mole h20=90

b). Ca=40
mg=26
240 g Ca=240/40=6 mol
240g mg=240/24=10
ratio=6:10=3:5