Two reactions are given below: C(graphite) + O2(g) → CO2(g); Δ H = - 393.7 kj ; C(diamond) → C(graphite); Δ H = -2.1 kj What quantity of diamond will give 800 kj of heat on burning?

Question

Two reactions are given below: C(graphite) + O2(g) → CO2(g); Δ H = - 393.7 kj ; C(diamond) → C(graphite); Δ H = -2.1 kj What quantity of diamond will give 800 kj of heat on burning? (A) 24.25 g (B) 15.24 g (C) 2 g (D) 12.12 g

Tardigrade Admin · Accepted Answer

C(diamond) → O2(g) → CO2(g) = -393.7 + (-2.1) = -395.8 kj 12 g diamond gives 395.8 kj. 800 kj will be given by (12/395.8)×800 = 24.25 g

Q. Two reactions are given below :
$C_{(g r a p hi t e)} + O_{2 (g)} \to C O_{2 (g)}; Δ H = - 393.7 kj$ ;
$C_{(d iam o n d)} \to C_{(g r a p hi t e)}; Δ H = - 2.1 kj$
What quantity of diamond will give $800 kj$ of heat on burning?

$24.25 g$

$15.24 g$

$2 g$

$12.12 g$

$C_{(d iam o n d)} \to O_{2 (g)} \to C O_{2 (g)}$
$= - 393.7 + (- 2.1) = - 395.8 kj$
$12 g$ diamond gives $395.8 kj$ .
$800 kj$ will be given by $\frac{12}{395.8} \times 800 = 24.25 g$

Q. Two reactions are given below : C(graphite)​+O2(g)​→CO2(g)​;ΔH=−393.7kj ; C(diamond)​→C(graphite)​;ΔH=−2.1kj What quantity of diamond will give 800kj of heat on burning?

24.25g

15.24g

2g

12.12g