I need help on an AS Level Paper 1 Chemistry question...

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Reply 20

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did u get an answer for this
if so then how do u do thi question??

Reply 21

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Original post by Giulia Z

Hi again! I was wondering if I could have some more help with the Summer 11, QP11 question 9?

9) 50 cm3 of 2.50 mol dm–3 hydrochloric acid was placed in a polystyrene beaker of negligible heat
capacity. Its temperature was recorded and then 50 cm3 of 2.50 mol dm–3 NaOH at the same
temperature was quickly added, with stirring. The temperature rose by 17 °C.

The resulting solution may be considered to have a specific heat capacity of 4.2 J g–1 K–1.

What is an approximate value for the molar enthalpy change of neutralisation of hydrochloric acid
and sodium hydroxide from this experiment?

A (5.2x050.0)/(17x2.4x50) J mol-1

B (5.2x10.0)/(17x2.4x50) J mol -1

C (5.2x050.0)/(17x2.4x100) J mol -1

D (5.2x50)/(17x2.4x100) J mol -1

The answer is C though I don't understand seeing as the mols of the two reactants need to be added together?