Given below are two statements:Assertion (A): | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The enthalpy of formation of a substance is defined as the change in enthalpy when $1 \ mol$ of a substance is formed from its constituent element

Vedclass · Accepted Answer

Both $(A)$ and $(R)$ are correct and $(R)$ is the correct explanation of $(A)$

Vedclass · Answer

(A) The enthalpy of formation of a substance is defined as the change in enthalpy when $1 \ mol$ of a substance is formed from its constituent elements in their most stable states at standard conditions ($298 \ K$ and $1 \ bar$ pressure).Since graphite is the most stable allotrope of carbon at standard conditions,its standard enthalpy of formation is defined as zero.Therefore,the Assertion $(A)$ is correct because it states the standard enthalpy of formation of graphite is zero.The Reason $(R)$ is also correct because the stability of graphite as the most stable allotrope is the fundamental reason why its enthalpy of formation is taken as zero.Thus,$(R)$ is the correct explanation of $(A)$.

Given below are two statements:
Assertion $(A)$: The enthalpy of formation of graphite is taken as zero.
Reason $(R)$: Graphite is the thermodynamically most stable allotrope of carbon.
The correct answer is:

Similar Questions

For the reaction,$3 C_2 H_{2(g)} \longrightarrow C_6 H_{6(g)}$,calculate the standard enthalpy change. The values of $\Delta H_f$ for $C_2 H_2$ and $C_6 H_6$ respectively are $250 \ kJ \ mol^{-1}$ and $90 \ kJ \ mol^{-1}$.

Explain the bond enthalpy.

If $C_{(s)} + O_{2(g)} \rightarrow CO_{2(g)}$,$\Delta H = -X$,and $CO_{(g)} + \frac{1}{2} O_{2(g)} \rightarrow CO_{2(g)}$,$\Delta H = -Y$,calculate $\Delta_f H$ for $CO_{(g)}$ formation.

$C + \frac{1}{2} O_2 \to CO; \Delta H = -42 \ kJ$
$CO + \frac{1}{2} O_2 \to CO_2; \Delta H = -24 \ kJ$
The heat of formation of $CO_2$ is ..... $kJ$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module

Given below are two statements:Assertion $(A)$: The enthalpy of formation of graphite is taken as zero.Reason $(R)$: Graphite is the thermodynamically most stable allotrope of carbon.The correct answer is: