Adding 43.1 cm3 of 11.6 moldm3 HCl to water to form 500cm3 of dilute solution, A temperature rise of 2.60 is observed, What is the enthalpy change of dilution of
hydrochloric acid?
(density of dilute solution = 1.00 g cm-3, specific heat capacity of dilute solution=
4.18 J g-1 K-1)
A. -5.45 kJmol-1
B. -10.9 kJmol-1
C. +5.45 kJmol-1
D. +10.9 kJmol-1
also,
Is it exothermic when there is a decrease of temperature during the reaction?
chemistry - enthalpy change
2012-10-05 5:09 am
回答 (2)
2012-10-05 7:37 am
✔ 最佳答案
The answer is : B. -10.9 kJ mol⁻¹An exothermic reaction (ΔH < 0) is a reaction in whichheat is given off. The heat given offrises the temperature of the surroundings. Since the temperature of surroundings is measured, then the temperature reading increases.
Heat given off = (500 x 1.00) x 4.18 x 2.60 = 5434 J = 5.434 kJ
No. of moles of HCl = 11.6 x (43.1/1000) = 0.49996 mol
Since temperature rises, the enthalpy change is exothermic, ΔH < 0.
Enthalpy change of dilution = -5.434/0.49996 = -10.9 kJ mol⁻¹
參考: micatkie
2012-10-09 5:01 am
The answer is B,I am sorry I cannot give you the explanation.
參考: The info. I know
收錄日期: 2021-04-13 19:03:18
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