What is the enthalpy of formation of water(l) in terms of X1,X2,X3,X4 is: (i) textH( textaq)+ + textOH( textaq)- arrow ( textH)2 textO (ℓ â) ; Δ textH = - textX1 text k J mol-1 (ii) ( textH)2 ( textg) + (1/2) ( textO)2 ( textg) arrow ( textH)2 textO (ℓ ) ; Δ textH = - textX2 text k J mol-1 (iii) ( textCO)2 ( textg) + ( textH)2 ( textg) arrow textCO ( textg) + ( textH)2 textO ; Δ textH = - textX3 text k J mol-1 (iv) ( textC)2 ( textH)2 ( textg) + (5/2) ( textO)2 ( textg) arrow 2 ( textCO)2 ( textg) + ( textH)2 textO (ℓ ) ; Δ textH = + 4 textX4 text k J mol-1

Question

What is the enthalpy of formation of water(l) in terms of X1,X2,X3,X4 is: (i) textH( textaq)+ + textOH( textaq)- arrow ( textH)2 textO (ℓ â) ; Δ textH = - textX1 text k J mol-1 (ii) ( textH)2 ( textg) + (1/2) ( textO)2 ( textg) arrow ( textH)2 textO (ℓ ) ; Δ textH = - textX2 text k J mol-1 (iii) ( textCO)2 ( textg) + ( textH)2 ( textg) arrow textCO ( textg) + ( textH)2 textO ; Δ textH = - textX3 text k J mol-1 (iv) ( textC)2 ( textH)2 ( textg) + (5/2) ( textO)2 ( textg) arrow 2 ( textCO)2 ( textg) + ( textH)2 textO (ℓ ) ; Δ textH = + 4 textX4 text k J mol-1 (A) - X2 k J m o l - 1 (B) + X1 k J m o l- 1 (C) + X3 k J m o l- 1 (D) - X4 k J m o l- 1

Tardigrade Admin · Accepted Answer

This reactions shows the formation of H2 O , and the - textX2 represents the enthalpy of formation of H2 O because as the definition suggests that the enthalpy of formation is the heat evolved or absorbed when one mole of substance is formed from its constituent elements in their standard form.

$- X_{2} k J m o l^{- 1}$

$+ X_{1} k J m o l^{- 1}$

$+ X_{3} k J m o l^{- 1}$

$- X_{4} k J m o l^{- 1}$

−X2​kJmol−1

+X1​kJmol−1

+X3​kJmol−1

−X4​kJmol−1

This reactions shows the formation of H2​O , and the −X2​ represents the enthalpy of formation of H2​O because as the definition suggests that the enthalpy of formation is the heat evolved or absorbed when one mole of substance is formed from its constituent elements in their standard form.

$- X_{2} k J m o l^{- 1}$

$+ X_{1} k J m o l^{- 1}$

$+ X_{3} k J m o l^{- 1}$

$- X_{4} k J m o l^{- 1}$