1. calculate the kilojoules of heat produced by the reaction, assuming that no e

Question

1. calculate the kilojoules of heat produced by the reaction, assuming that no energy left the calorimeter. The specific heat of the solution is 3.96 J/g-°C (include the mass of the aluminum foil in the total mass of the solution).

2. Calculate the change in enthalpy of reaction for each trial, express as kilojoules per mole of solid copper (II) chloride dihydrate reacted. Be sure to include correct sign for ?H.

3. We assume in the calculations that no energy leaked from the calorimeter. In reality it this true? What other factors would have to be considered to get a more accurate meassure of the total heat of the reaction?

4. Is this an exothermic or an endothermic reaction? Does the sign of your  ?H shown (from calculations) correacly indicate this? If not, why doesn't it?

Mass of calorimeter Mass of solid CuCl2·2H2O Mass of copper solution Mass of aluminum foil Initial temperature Final temperature TRIAL 1 5.434 g 3.000 g 67.360 g 0.822 g 26.6oC 53.2 C TRIAL 2 5.678 g 3.082 g 62.828 g 0.844 g 26.7°C 56.1

Explanation / Answer

1. Heat produced q = mCpdT

Trial 1

q = (67.360 + 0.822) x 3.96 x (53.2 - 26.6) = 7.1820 kJ

Trial 2

q = (62.828 + 0.844) x 3.96 x (56.1 - 26.7) = 7.4129 kJ

2. Change in enthalpy dH = -q

For trial 1

moles of CuCl2.2H2O = 3.0 g/170.4826 g/mol = 0.0176 mols

dH = -7.1820/0.0176 = -408.135 kJ/mol

For trial 2

moles of CuCl2.2H2O = 3.082 g/170.4826 g/mol = 0.0181 mols

dH = -7.4129/0.0181 = -409.55 kJ/mol

3. The heat has not left the calorimeter. Other fators to be considered would be the amount of heat needed to heat up the solution before reaction occured.

4. The reaction is exothermic. The sign of dH shows -ve which stands for an exothermic reaction.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.