Balance the following equations: i. H2SO4 + ….NaHCO3 → Na2SO4 + ….H2O + ……CO2
ii. H2 + I2 → ….HI
iii. …..NaOH + H2SO4 → Na2SO4 + …..H2O
iv. ……FeSO4 → Fe2O3 + SO2 + SO3
v. C3H6O2 + …..O2 → ….CO2 + …..H2O
b) Calculate the molecular masses of the following:
i. H2SO4

ii. CH4

iii. NH3

c) 56g of iron reacts with 71g of chlorine. How many grams of iron react with 35.5g of chlorine?

(I)

(II)

(III)

(IV)

(V)

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(I)

(ANS)

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Solution:

Molecular mass of,

H = 1

S = 32

O = 16

Now,

There are 2 atoms of Hydrogen, 1 atoms of Sulfur and 4 atoms of Oxygen present, thus,

(II)

(ANS)

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Solution:

Molecular Mass,

Carbon = 12

Hydrogen = 1

Now

There are 1 atom of Oxygen and 4 atoms of Hydrogen present, thus,

(III)

(ANS)

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Solution:

Molecular Mass,

Nitrogen = 14 grams

Hydrogen = 1

Now,

There are 1 atoms of Nitrogen and 3 atoms of Hydrogen present, thus,

56     71

x       35.5

Simplify the equation

X = 28 grams

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28 grams of Iron(fe) will react with chlorine.

the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.