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    http://pmt.physicsandmathstutor.com/...%20Entropy.pdf

    Question 7a and question 9a
    I understand the questions but got a bit confused by the markscheme
    It says:
    For 7a. Standard enthalpy change: ΔHR = ΣΔ Hf products – ΣΔ Hf
    For 9a. ΔHa = ∑ ΔHf products – ∑ ΔHf reactants or
    = ΔHf CO2– (ΔHf CH4 + 2 ΔHf H2O) (1)

    Why is it calculating ΔHR in 7a but in 9a it is ΔHa?
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    (Original post by chemquestion)
    Why is it calculating ΔHR in 7a but in 9a it is ΔHa?
    Both calculations are to find DrH.
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    (Original post by Pigster)
    Both calculations are to find DrH.
    What does DrH mean?
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    Enthalpy change of reaction.
 
 
 
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