Answers

2016-03-26T17:55:20+05:30
CrO₅ + H₂SO₄ → Cr₂(SO₄)₃ + H₂O + O₂ is the given reaction.
if we balance the reaction it would be
4(CrO₅) + 6(H₂SO₄) → 2(Cr₂(SO₄)₃ )+ 6(H₂O) + 7C
therefore 7 moles of  O₂ will be liberated

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2016-03-26T19:32:04+05:30
This is an authentic method, {it was confirmed that c_1 = 1}

Balance the chemical equation:

CrO5 + H_2SO_4 --> Cr_2(SO_4)_3 + H_2O + O_2

Add coefficients to all the molecules:

c_1 CrO5 + c_2 H_2SO_4 --> c_3 Cr_2(SO_4)_3 + c_4 H_2O + c_5 O_2

The number of Cr, O, H, and S atoms on both sides of the reaction must be equal:

Cr: | c_1 = 2 c_3

O: | 5 c_1+4 c_2 = 12 c_3+c_4+2 c_5

H: | 2 c_2 = 2 c_4

S: | c_2 = 3 c_3

Since the coefficients are only determined up to a multiplicative constant, set c_3 = 1 and solve for the
coefficients:

c_1 = 2
c_2 = 3c_3 = 1c_4 = 3c_5 = 7/2

Since one of the coefficients is a fraction, set c_3 = 2 and repeat the step above to obtain integer 
coefficients:

c_1 = 4
c_2 = 6c_3 = 2c_4 = 6c_5 = 7

Since the coefficients are all integers with a greatest common denominator = 1, 

Substitute the
coefficients into the chemical reaction to obtain the balanced equation:4

CrO5 + 6 H_2SO_4 --> 2 Cr_2(SO_4)_3 + 6 H_2O + 7 O_2

Now the number of moles of O2 obtained is 7


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