What do you understand by exothermic reaction and endothermic reaction? Give one example of each type.
(N/A) Exothermic reactions: Reactions which evolve heat are known as exothermic reactions. Evolution of heat can be shown using a '$+$' sign or by a $\Delta H$ with a '$-$' sign along with the product.
Example: $C_{(s)} + O_{2(g)} \longrightarrow CO_{2(g)} + 393.5 \ kJ$
Endothermic reactions: Reactions which absorb heat are called endothermic reactions. Absorbed heat can be shown as a '$-$' sign or in terms of $\Delta H$ with a '$+$' sign.
Example: $C_{(s)} + H_{2}O_{(g)} \longrightarrow CO_{(g)} + H_{2(g)} - 131.4 \ kJ$
Example: $C_{(s)} + O_{2(g)} \longrightarrow CO_{2(g)} + 393.5 \ kJ$
Endothermic reactions: Reactions which absorb heat are called endothermic reactions. Absorbed heat can be shown as a '$-$' sign or in terms of $\Delta H$ with a '$+$' sign.
Example: $C_{(s)} + H_{2}O_{(g)} \longrightarrow CO_{(g)} + H_{2(g)} - 131.4 \ kJ$
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Similar Questions
If the enthalpy of atomisation for $Br_{2(l)}$ is $x \ kJ/mol$ and the bond enthalpy for $Br_{2(g)}$ is $y \ kJ/mol$,what is the relation between them?
DifficultJEE MAIN 2020
View SolutionOn the basis of the thermochemical equations:
$H_{2}O_{(g)} + C_{(s)} \to CO_{(g)} + H_{2(g)} \quad \Delta H = 131 \ kJ$
$CO_{(g)} + \frac{1}{2} O_{2(g)} \to CO_{2(g)} \quad \Delta H = -282 \ kJ$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \to H_{2}O_{(g)} \quad \Delta H = -242 \ kJ$
$C_{(s)} + O_{2(g)} \to CO_{2(g)} \quad \Delta H = X \ kJ$
The value of $X$ will be $.... \ kJ$.
$H_{2}O_{(g)} + C_{(s)} \to CO_{(g)} + H_{2(g)} \quad \Delta H = 131 \ kJ$
$CO_{(g)} + \frac{1}{2} O_{2(g)} \to CO_{2(g)} \quad \Delta H = -282 \ kJ$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \to H_{2}O_{(g)} \quad \Delta H = -242 \ kJ$
$C_{(s)} + O_{2(g)} \to CO_{2(g)} \quad \Delta H = X \ kJ$
The value of $X$ will be $.... \ kJ$.
Medium
View SolutionConsider the following data:
Heat of combustion of $H_{2(g)} = -241.8 \ kJ \ mol^{-1}$
Heat of combustion of $C_{(s)} = -393.5 \ kJ \ mol^{-1}$
Heat of combustion of $C_2H_5OH_{(l)} = -1234.7 \ kJ \ mol^{-1}$
The heat of formation of $C_2H_5OH_{(l)}$ is $(-)$ $...... \ kJ \ mol^{-1}$ (Nearest integer).
Heat of combustion of $H_{2(g)} = -241.8 \ kJ \ mol^{-1}$
Heat of combustion of $C_{(s)} = -393.5 \ kJ \ mol^{-1}$
Heat of combustion of $C_2H_5OH_{(l)} = -1234.7 \ kJ \ mol^{-1}$
The heat of formation of $C_2H_5OH_{(l)}$ is $(-)$ $...... \ kJ \ mol^{-1}$ (Nearest integer).
$CuSO_{4(s)} + 5 H_2O_{(\ell)} \rightarrow CuSO_4 \cdot 5 H_2O_{(s)} ; \Delta H = -x \ kJ$. The value of $\Delta H$ represents:
Medium
View SolutionThe heat of combustion of solid benzoic acid at constant volume is $-321.30 \ kJ$ at $27^{\circ} C$. Its heat of combustion at constant pressure is :
Medium
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