Determine the heat of transformation of
$C_{(d i a m o n d)} \to C_{(g r a p h i t e)}$ from the following data
$C_{(d i a m o n d)} + O_{2} (g) \to C {C O}_{2} (g); (Δ H = - 94.5 k c a l)$
$C_{(g r a p h i t e)} + O_{2} (g) \to C {C O}_{2} (g); (Δ H = - 94.0 k c a l)$

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Solution

$C_{(d i a m o n d)} + O_{2} (g) \to C {C O}_{2} (g); Δ H = - 94.5 k c a l) . . . . (i)$
$C_{(g r a p h i t e)} + O_{2} (g) \to C {C O}_{2} (g); Δ H = - 94.0 k c a l) . . . . . (i i)$
Subtracting eq(ii) from (i) the required equation is obtained
$Δ H_{t r a n s f o r m a t i o n} = - 94.5 - (- 94.0)$
$= - 0.5 k c a l$

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Similar questions

C_{(d i a m o n d)} + O_{2} (g) \to C O_{2} (g) △ H = - 94.5 K c a l

C_{(g r a p h i t e)} + O_{2} (g) \to C O_{2} (g) △ H = - 94.0 K c a l

C_{d i a m o n d} \to C_{(g r a p h i t e)}

(i n k c a l)

C_{(d i o m o n d)} + O_{2} (g) \to C O_{2} (g) . . . (i) (Δ H = - 94.5 k c a l) C_{(g r a p h i t e)} + O_{2} (g) \to C O_{2} (g) . . . (i i) (Δ H = - 94.0 k c a l)

Δ H

C (g r a p h i t e) \to C (d i a m o n d)

C (g r a p h i t e) + O_{2} (g) ⟶ C O_{2} (g); Δ H^{o} = - 393.5 k J

C (g r a p h i t e) + O_{2} (g) ⟶ C O_{2} (g); Δ H^{o} = - 395.4 k J

Assertion- $C (g r a p h i t e) + O_{2 (g)} \to C O_{2 (g)}$ ,

$Δ H = - 393.5 k . J$

$C (d i a m o n d) + O_{2 (g)} \to C O_{2 (g)}$ ,

$Δ H = - 395.4 k . J$

Reason(R): graphite is more stable than diamond, so heat of combustion is less.

C_{(g r a p h i t e)} + O_{2 (g)} \to C O_{2 (g)}; Δ H = - 393.7 k J

C_{(d i a m o n d)} \to C_{(g r a p h i t e)}; Δ H = - 2.1 k J

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