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Given:
$straight N subscript 2 left parenthesis straight g right parenthesis space plus space 3 straight H subscript 2 left parenthesis straight g right parenthesis space rightwards arrow space space 2 NH subscript 3 left parenthesis straight g right parenthesis semicolon space space space space space space space space space space space space space space space space space space increment subscript straight r straight H to the power of 0 space equals space minus 92.4 space kJ space mol to the power of negative 1 end exponent$
What is the standard enthalpy of formation of NH₃ gas?

The enthalpy of formation of ammonia is the enthalpy change for the formation of 1 mole of ammonia from its elements.
Given that enthalpy of formation for 2 moles of NH₃ = –92.4 kJ

Therefore, standard enthalpy of formation for

Hence standard enthalpy of formation for NH₃

191 Views

How much heat is evolved when 204g of ammonia are produced according to the equation,
$space straight N subscript 2 left parenthesis straight g right parenthesis space plus space 3 straight H subscript 2 left parenthesis straight g right parenthesis space rightwards arrow space space 2 NH subscript 3 left parenthesis straight g right parenthesis semicolon space increment straight H space equals space 92.6 space kJ$

2 mol i.e. 34 g of NH₃ produced are accompanied by the evolution of 92.6 kJ of heat.
So, 204 g of NH₃ produced would be accompanied by evolution of

106 Views

What do you mean by the standard enthalpy of combustion?

Standard enthalpy of combustion is defined as the enthalpy per mole of the substance, all the reactants and products being in their standard states i.e. at 298K and 1 bar pressure. It is denoted by ∆_CH°.

(i) Combustion of butane:

(ii) Combustion of glucose:

109 Views

Combustion of glucose is according to the following reaction:

straight C subscript 6 straight H subscript 12 straight O subscript 6 left parenthesis straight s right parenthesis space plus space 6 straight O subscript 2 left parenthesis straight g right parenthesis space rightwards arrow space space 6 CO subscript 2 left parenthesis straight g right parenthesis space plus space 6 straight H subscript 2 straight O left parenthesis straight g right parenthesis semicolon space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space increment straight H space equals space minus 250 space kJ

How much heat energy is needed for the formation of 1.8g of glucose?

The formation of glucose can be represented by reversing the reaction.

Gram molecular mass of

= 12 x 6 + 12 x 1 + 6 x 16
= 180 g
Heat energy needed to form 180 g of glucose = 250 kJ
Heat energy needed to form 1.8 g of glucose

111 Views

What will be the amount of heat evolved when 39 gm of C₆H₆(l) are burnt? Given that:
$straight C subscript 6 straight H subscript 6 left parenthesis straight l right parenthesis space plus space 15 over 2 straight O subscript 2 left parenthesis straight g right parenthesis space space rightwards arrow space space 3 straight H subscript 2 straight O left parenthesis straight l right parenthesis space plus space 6 CO subscript 2 left parenthesis straight g right parenthesis semicolon increment straight H space equals space minus 3264.6 space kJ space mol to the power of negative 1 end exponent$