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Convert between dU and dH for a reaction using the change in gas moles

This type of question, asked 5 times: 26 Jun 2022, 28 Jun 2022, 26 Jul 2022, 8 Apr 2023, 5 Apr 2024. All 5 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    26 Jun 2022

    51
    For complete combustion of methanol
    CH3OH(l)+32O2( g)→CO2( g)+2H2O(l)CH_{3}OH(l) +\frac{3}{2}O_{2}(\text{ }g) \rightarrow CO_{2}(\text{ }g) + 2H_{2}O(l)
    the amount of heat produced as measured by bomb calorimeter is 726 kJ mol−1726\text{ }kJ{\text{ }mol}^{- 1} at 27∘C27^{\circ}C. The enthalpy of combustion for the reaction is −xkJmol−1- xkJmol^{- 1}, where xx is ____\_\_\_\_. (Nearest integer) (Given: R=8.3JK−1 mol−1R = 8.3JK^{- 1}{\text{ }mol}^{- 1} )

  2. Question 2

    28 Jun 2022

    142
    For combustion of one mole of magnesium in an open container at 300 K300\text{ }K and 1 bar pressure, ΔCH⊖\Delta_{C}H^{\ominus} =−601.70 kJ mol−1= - 601.70\text{ }kJ{\text{ }mol}^{- 1}, the magnitude of change in internal energy for the reaction is ____\_\_\_\_ kJkJ. (Nearest integer) (Given: R=8.3 J K−1 mol−1R = 8.3\text{ }J{\text{ }K}^{- 1}{\text{ }mol}^{- 1} )

  3. Question 3

    26 Jul 2022

    143
    For the reaction
    H2 F2( g)→H2( g)+F2( g)H_{2}{\text{ }F}_{2}(\text{ }g) \rightarrow H_{2}(\text{ }g) +F_{2}(\text{ }g)
    ΔU=−59.6 kJ mol−1\Delta U = - 59.6\text{ }kJ{\text{ }mol}^{- 1} at 27∘C27^{\circ}C. The enthalpy change for the above reaction is (−)( - ) ____\_\_\_\_ kJmol−1kJmol^{- 1} [nearest integer] Given: R=8.314R = 8.314 JK−1 mol−1JK^{- 1}{\text{ }mol}^{- 1}.

  4. Question 4

    8 Apr 2023

    144
    For complete combustion of ethene. C2H4( g)+3O2( g)→2CO2( g)+2H2O(l)C_{2}H_{4}(\text{ }g) + 3O_{2}(\text{ }g) \rightarrow 2CO_{2}(\text{ }g) + 2H_{2}O(l) the amount of heat produced as measured in bomb calorimeter is 1406 kJ mol−11406\text{ }kJ{\text{ }mol}^{- 1} at 300 K300\text{ }K. The minimum value of TΔST\Delta S needed to reach equilibrium is (−)( - ) ____kJkJ. (Nearest integer) Given: R=8.3JK−1 mol−1R = 8.3JK^{- 1}{\text{ }mol}^{- 1}

  5. Question 5

    5 Apr 2024

    53
    The heat of combustion of solid benzoic acid at constant volume is −321.30 kJ- 321.30\text{ }kJ at 27∘C27^{\circ}C. The heat of combustion at constant pressure is (−321.30−xR)( - 321.30 - xR) kJkJ, the value of xx is ______