(C) The molar enthalpy of vaporisation is the enthalpy change for the process: $H_2O_{(l)} \to H_2O_{(g)}$.We are given:$(I) \ H_{2(g)} + \frac{1}{2}O

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(C) The molar enthalpy of vaporisation is the enthalpy change for the process: $H_2O_{(l)} \to H_2O_{(g)}$.We are given:$(I) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(l)}; \Delta H^o_1 = -285.9 \ kJ \ mol^{-1}$$(II) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(g)}; \Delta H^o_2 = -241.8 \ kJ \ mol^{-1}$To obtain the target equation,subtract equation $(I)$ from equation $(II)$:$(II) - (I): H_2O_{(l)} \to H_2O_{(g)}$$\Delta H^o_{vap} = \Delta H^o_2 - \Delta H^o_1$$\Delta H^o_{vap} = -241.8 - (-285.9) \ kJ \ mol^{-1}$$\Delta H^o_{vap} = 44.1 \ kJ \ mol^{-1}$

Class 11 Chemistry Thermodynamics Heat of reaction, Bond energy and Hess law

Difficult

Given:
$(I) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(l)}; \Delta H^o_{298\ K} = -285.9 \ kJ \ mol^{-1}$
$(II) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(g)}; \Delta H^o_{298\ K} = -241.8 \ kJ \ mol^{-1}$
The molar enthalpy of vaporisation of water will be $kJ \ mol^{-1}$.

JEE MAIN 2013 All JEE MAIN

A
$241.8$
B
$22$
C
$44.1$
D
$527.7$

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Class 11

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Thermodynamics

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Heat of reaction, Bond energy and Hess law

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The energy required to break one mole of $Cl-Cl$ bonds in $Cl_2$ is $242 \, kJ \, mol^{-1}.$ The longest wavelength of light capable of breaking a single $Cl-Cl$ bond is $............ \, nm.$
$(c = 3 \times 10^8 \, m \, s^{-1}$ and $N_A = 6.02 \times 10^{23} \, mol^{-1}).$

MediumAIEEE 2010

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The combustion enthalpies of carbon,hydrogen,and methane are $-393.5 \ kJ/mole$,$-284.8 \ kJ/mole$,and $-890.4 \ kJ/mole$ respectively at $25 \ ^oC$. The value of the standard formation enthalpy of methane at that temperature is ..... $kJ/mole$.

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The calorific value of glucose is ...... $KJ/g$. Given: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O ; \Delta H = -2900 \, KJ/mol$.

Medium

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The heat of solution of anhydrous $CuSO_4$ and $CuSO_4 \cdot 5 H_2 O$ are $-70 \ kJ \ mol^{-1}$ and $+12 \ kJ \ mol^{-1}$ respectively. The heat of hydration of $CuSO_4$ to $CuSO_4 \cdot 5 H_2 O$ is $-x \ kJ$. The value of $x$ is:

MediumJEE MAIN 2024

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When $50 \ cm^3$ of a strong acid is added to $50 \ cm^3$ of an alkali,the temperature rises by $5 \ ^oC$. If $250 \ cm^3$ of each liquid are mixed,the temperature rise would be $... \ ^oC$.

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Given:$(I) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(l)}; \Delta H^o_{298\ K} = -285.9 \ kJ \ mol^{-1}$$(II) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(g)}; \Delta H^o_{298\ K} = -241.8 \ kJ \ mol^{-1}$The molar enthalpy of vaporisation of water will be $kJ \ mol^{-1}$.

Similar Questions

The energy required to break one mole of $Cl-Cl$ bonds in $Cl_2$ is $242 \, kJ \, mol^{-1}.$ The longest wavelength of light capable of breaking a single $Cl-Cl$ bond is $............ \, nm.$$(c = 3 \times 10^8 \, m \, s^{-1}$ and $N_A = 6.02 \times 10^{23} \, mol^{-1}).$

The combustion enthalpies of carbon,hydrogen,and methane are $-393.5 \ kJ/mole$,$-284.8 \ kJ/mole$,and $-890.4 \ kJ/mole$ respectively at $25 \ ^oC$. The value of the standard formation enthalpy of methane at that temperature is ..... $kJ/mole$.

The calorific value of glucose is ...... $KJ/g$. Given: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O ; \Delta H = -2900 \, KJ/mol$.

The heat of solution of anhydrous $CuSO_4$ and $CuSO_4 \cdot 5 H_2 O$ are $-70 \ kJ \ mol^{-1}$ and $+12 \ kJ \ mol^{-1}$ respectively. The heat of hydration of $CuSO_4$ to $CuSO_4 \cdot 5 H_2 O$ is $-x \ kJ$. The value of $x$ is:

When $50 \ cm^3$ of a strong acid is added to $50 \ cm^3$ of an alkali,the temperature rises by $5 \ ^oC$. If $250 \ cm^3$ of each liquid are mixed,the temperature rise would be $... \ ^oC$.

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Given:
$(I) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(l)}; \Delta H^o_{298\ K} = -285.9 \ kJ \ mol^{-1}$
$(II) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(g)}; \Delta H^o_{298\ K} = -241.8 \ kJ \ mol^{-1}$
The molar enthalpy of vaporisation of water will be $kJ \ mol^{-1}$.

The energy required to break one mole of $Cl-Cl$ bonds in $Cl_2$ is $242 \, kJ \, mol^{-1}.$ The longest wavelength of light capable of breaking a single $Cl-Cl$ bond is $............ \, nm.$
$(c = 3 \times 10^8 \, m \, s^{-1}$ and $N_A = 6.02 \times 10^{23} \, mol^{-1}).$