Short Answer TypeThe enthalpy change (∆H) for the reaction
is -92.38 kJ at 298 K. what is the 
at 298 K?
∆U⊝ of combustion of methane is –X kJ mol–1. The value of ∆H⊝ is :
(i) = ∆U⊝
(ii) > ∆U⊝
(iii) < ∆U⊝
(iv) = 0
Long Answer Type
Short Answer TypeWhat do you understand by:
(i) Heat capacity of a substance
(ii) Heat capacity at constant volume
(iii) Heat capacity at constant pressure?
(i) Heat capacity: The heat capacity (C) of a sample of a substance is the quantity of heat needed to raise its temperature by 1°C (or one kelvin).
(ii) Heat capacity at constant volume: The heat supplied to a system to raise its temperature through 1°C keeping the volume of the system constant is called heat capacity at constant volume.
(iii) Heat capacity at constant pressure: The heat supplied to a system to raise its temperature through 1 °C keeping the external pressure constant is called heat capacity at constant pressure.
If q is the amount of heat supplied to a sample and as a result, if the temperature of the sample changes from initial temperature to a final temperature tf, then the heat capacity is given by
60.8 J of energy is required to change the temperature of 25.0 g of ethylene glycol (a compound used as an antifreeze in automobile engines) by 1.0 K. Calculate heat capacity of ethylene glycol.
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