#1. How much heat is absorbed during production of 158 g of NO by the combinatio

ID: 897906 • Letter: #

Question

#1. How much heat is absorbed during production of 158 g of NO by the combination of nitrogen and oxygen?
N2(g)+O2(g)2NO(g), H = + 43.0 kcal

Answer as a positive value to the correct number os significant figures.

#2. For the production of ammonia from its elements, 3H2(g)+N2(g)2NH3(g),
H = -21.9 kcal.

- How many kilocalories are involved in the production of 30.46 g of NH3?

-How many kilocalories are involved if 16.34 g of H2 are consumed in this reaction?

- Is this process endothermic or exothermic?

(1) N2(g)+O2(g) 2NO(g), H = + 43.0 kcal

Molar mass of NO = At.mass of N + At.mass of O

= 14 + 16

= 30 g/mol

From the balanced equation ,

On production of 2 moles of NO it absorbs 43.0 kCal of heat

On production of 2x30 g of NO it absorbs 43.0 kCal of heat

On production of 158 g of NO it absorbs M kCal of heat

M = (158 x 43.0) / (2x30)

= 113.2 kCal of heat

So the correct answer is +113.2 kCal

(2) 3H2(g)+N2(g)2NH3(g),H = -21.9 kcal.

(i) Molar mass of NH3 = At.mass of N + ( 3xAt.mass of H )

= 14 + (3x1)

= 17 g/mol

From the balanced equation ,

on production of 2 moles of NH3 the amount of heat released is 21.9 kCal

on production of 2x17 g of NH3 the amount of heat released is 21.9 kCal

on production of 30.46 g of NH3 the amount of heat released is N kCal

N = ( 30.46 x 21.9 ) / ( 2x17)

= 19.6 kCal

(ii) Molar mass of H2 = 2xAt.mass of H = 2x1 = 2 g/mol

From the balanced equation ,

3 moles of H2 produces 21.9 kCal of heat

3x2 g of H2 produces 21.9 kCal of heat

16.34 g of H2 produces Y kCal of heat

Y = ( 16.34 x 21.9 ) / (3x2)

= 59.6 kCal of heat

(iii) Since the value of H is -ve , it clearly indicates the reaction is exothermic reaction.

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