Please Answer This 2 Questions
Answers
1 )
The total sum of the masses of the atoms or elements present in the molecule is termed as molecular mass.
i) Molecular mass of H2= 2 x Atomic mass of H
= 2 x 1
Molecular mass of H2 = 2 u
ii) Molecular mass of O2= 2 x Atomic mass of O
= 2 x 16
Molecular mass of O2= 32 u
iii) Molecular mass of Cl2= 2 x Atomic mass of Cl
= 2 x 35.5
Molecular mass of Cl2 = 71 u
iv) Molecular mass of CO2= Atomic mass of C + 2 x Atomic mass of O
= 12 + 2 x 16
Molecular mass of CO2 = 44 u
v) Molecular mass of CH4= Atomic mass of C + 4 x Atomic mass of H
= 12 + 4 x 1
Molecular mass of CH4 = 16 u
vi) Molecular mass of C2H6= 2 x Atomic mass of C + 6 x Atomic mass of H
= 2 x 12 + 6 x 1
Molecular mass of C2H6 = 30 u
vii) Molecular mass of C2H4= 2 x Atomic mass of C + 4 x Atomic mass of H
= 2 x 12 + 4 x 1
Molecular mass of C2H4 = 28 u
viii) Molecular mass of NH3= Atomic mass of N + 3 x Atomic mass of H
= 14 + 3 x 1
Molecular mass of NH3 = 17 u
ix) Molecular mass of CH3OH= Atomic mass of C + 4 x Atomic mass of H + 1 x Atomic mass of
= 12 + 4 x 1 + 16
Molecular mass of CH3OH = 32 u
2) Formula unit mass is defined as the sum of the atomic masses of all atoms that are present in a formula unit of the given compound.
Atomic mass of Zn = 65u
Atomic mass of Na = 23u
Atomic mass of K = 39u
Atomic mass of C = 12u
Atomic mass of O = 16u
Calculating the formula unit masses of the given compounds:
ZnO = Zn + O
ZnO = (65 + 16)u = 81u
Na2O = 2Na + O
Na2O = [(2 x 23)+16]u
Na2O = (46 + 16)u = 62u
K2CO3 = 2K + C + 3O
K2CO3 = [(2 x 39) + 12 + (3×16)]
K2CO3 = (78 + 12 + 48)u = 138u
Hence, the formula unit mass of ZnO is 81u, Na2O is 62u and K2CO3 is 138u.
Answer:
☝️Q. no.2
Q. no. 1
Solution
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Molecular mass of the given molecules are calculated below:-
H
2
= 2×1=2 g/mol
O
2
= 2×16=32 g/mol
Cl
2
= 2×35.5=71 g/mol
CO
2
= 1×C+2×16=44 g/mol
CH
4
= 1×12+4×1=16 g/mol
C
2
H
6
= 2×12+6×1=30 g/mol
C
2
H
4
= 2×12+4×1=28 g/mol
NH
3
= 1×14+3×1=17 g/mol
CH
3
OH = 1×12+4×1+1×16=32 g/mol
Q no. 2
