Heat of neutralization

[匿名]

2013-04-05 8:05 am

(1) 50cm3 1M NaOH + 50 cm3 1M HCl
(2) 50cm3 2M NaOH + 50 cm3 2M HCl

Questions:True or False , and why?

1/ Heat energy produced in (1)and(2) are the same.
2/ the rise in temperature in (2) is higher then that in (1)

Another questions:
3/ How does the rise in temperature change if the volume of both the acid and
alkali in (1) increases by 50 cm3?

4/How does the amount of heat energy produced change if the volume of both the acid and alkali in (1) increases by 50 cm3?

Conclusion : what is the relationship between heat energy produced and molarity of acid and alkali in a complete neutralization?

I have got confused with these things.
THANKS A LOT!!!

回答 (1)

放 rakion acc

2013-04-07 1:40 am

✔ 最佳答案

1/ false, because there is more reacting agents in the case of 2, so more heat energy will be released by the second reaction

2/ true. because the resultant mixtures have the same volume, and the energy given by the reaction involved in 2 is higher, so the temperature increase is higher.

3/ the rise in temperature remains unchanged. since the number of moles of reactants per unit volume of mixture is still the same. by E=mc (delta t), increase in temperature is the same.

4/ heat energy produced is doubled.

conclusion: for a complete neutralization, the heat energy produced depends on the number of moles of reactants, which in turn equal to the molarity times the volume of reactant.
However, the temperature increase is independent on the volume of reactants!

2013-04-08 03:35:02 補充：
do you understand what i am talking about :)

參考: AL chem A

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