Question

Given the equations below, which description applies to the conversion of diamond to graphite? C(s, diamond) + O2 (g) → CO2 (g), ∆H = –395.4 kJ CO2 (g) → C(s, graphite) + O2 (g), ∆H = 393.5 kJ Please explain your answer
A) Energy is created during the process.

B) Heat is neither released nor absorbed during the process.

C) Heat is released during the process.

D) The process is endothermic.

Answer 1

ans D) the process is endothermic

C(s, diamond + O2 (g)-->CO2(g),∆H= -395.5kJ

Answer 2

Answer: The correct answer is Option C.

Explanation:

We are given two reactions:

$C\text{(s,diamond)}+O_2(g)\rightarrow CO_2(g);\Delta H=-395.4kJ$     ....(1)

$CO_2(g)\rightarrow \text{(s, graphite)}+O_2(g); \Delta H=393.5kJ$     ....(2)

According to Hess’s law of constant heat summation, the heat absorbed or released in a given chemical equation is the same whether the process occurs in one step or several steps.

For the reaction of conversion of diamond to graphite, the equation follows:

$C\text{(s,diamond)}\rightarrow C\text{(s,graphite)}$

The enthalpy of the above reaction is given as:

$\Delta H_{rxn}=\Delta H_1+\Delta H_2\\\\\Delta H_{rxn}=(-395.5+393.5)kJ=-2kJ$

As, the enthalpy change for the reaction is coming out to be negative. Thus, it is getting released during the process.

Hence, the correct answer is Option C.