Q. 255.0( 4 Votes )
Find the ratio by mass of the combining elements in the following compounds. (You may use Appendix-III)
(a) CaCO3
(b) MgCl2
(c) H2SO4
(d) C2H5OH
(e) NH3
(f) Ca(OH)2
Answer :
(a) CaCO3
Atomic mass of Ca = 40
Atomic mass of C = 12
Atomic mass of O = 16
Thus, CaCO3 = 40 : 12 : 16 × 3
= 40 : 12 : 48
Ratio by mass = 10 : 3 : 12
(b) MgCl2:
Atomic mass of Mg = 24
Atomic mass of Cl = 35.5
Thus, the ratio by mass = Mg : Cl x 2
= 24 : 35.5 x 2
= 24 : 71
(c) H2SO4:
Atomic mass of H = 1
Atomic mass of S = 32
Atomic mass of O = 16
Thus, the ratio by mass = 2XH : S : 4XO
= 2 : 32 : 64
= 1 : 16 : 32
(d) C2H5OH
The ratio by mass = 2XC : 6XH : O
= 2X12 : 6 : 16
= 24 : 6 : 16
= 12 : 3 : 8
(e) NH3
The ratio by mass = N : 3 × H
14 : 1
(f) Ca(OH)2
The ratio by mass = Ca : 2XO : 2 × H
= 40 : 32 : 2
= 20 : 16 : 1
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