1,674
26
Essay, 2 pages (500 words)

Enthalpy change of a displacement reaction essay sample

To determine the enthalpy change of a displacement reaction (Between zinc and copper (II) ions)

5. Introduction :

Excess zinc powder is added in a measured amount of aqueous copper (II) sulphate. The temperature change is then measured over a period of time so the enthalpy of this reaction can be calculated.

6. Relevant Equations/Chemical Reactions Involved :

Zn (s) + CuSO4(aq) ?? ZnSO4(aq) + Cu(s)

7. Chemicals :

1. 00M copper (II) sulphate solution 25. 0 cm3

Zinc powder (in excess) 5. 9g

8. Apparatus and equipment :

Safety spectacle x 1 Spatula x 1

25 cm3 pipette x 1 Balance x 1

Pipette filler x 1 Thermometer(0-100 oC) x 1

Polystyrene cup with lid x 1 Digital timer x 1

Weighting bottle x 1

9. Procedure :

1. An empty polystyrene cup was weighted.

2. 5. 9g of zinc powder (in excess)was weighted and then added into the polystyrene cup.

3. The temperature of the copper (II) sulphate solution in beaker was recorded every half minute for 2. 5 minutes and then 25. 0 cm3 of the copper (II) sulphate solution was pipetted into a polystyrene cup.

4. Thermometer was put through the hole of the lid. The solution was stirred continuously and the temperature was recorded every half minute for 6 minutes.

10. Observation :

The blue colour of the solution disappears. Brown solid is formed. Some zinc powder remains there.

11. Data, Calculation and Results :

a. Results Table

Time/min

0. 0

0. 5

1. 0

1. 5

2. 0

2. 5

3. 0

3. 5

4. 0

4. 5

Temperature/oC

25. 0

25. 0

25. 0

25. 0

25. 0

25. 0

25. 0

60. 0

73. 0

71. 0

Time/min

5. 0

5. 5

6. 0

6. 5

7. 0

7. 5

8. 0

8. 5

9. 0

9. 5

Temperature/oC

69. 0

68. 0

67. 0

65. 5

64. 5

63. 5

62. 5

61. 5

60

59

b. Calculations

1&2. Graph of temperature against time

3. Energy change of solution = 25 x 10-3 x 4. 18 x (76. 5 – 25)

= 5. 38175 kJ mol-1

Energy change of the cup = 2. 27 x 10-3 x 1. 3 x (76. 5- 25)

= 0. 1519765 kJ mol-1

Enthalpy change for the quantities used = – (5. 38175 + 0. 1519765)

= – 5. 5337265 kJ mol-1

Assumptions :

(1) The specific heat capacity of the solution is the same as that of water.

(2) Heat is not lost to the surrounding.

4. No. of mole of CuSO4 = 1 x 25 x 10-3 = 0. 025 mol

Required enthalpy change = – [(5. 5337265)/0. 025]

= – 221 kJ mol-1

Zn (s) + CuSO4(aq) ?? ZnSO4(aq) + Cu(s) ? H = – 221 kJ mol-1

12. Conclusion :

It was found that the enthalpy change of a displacement reaction (Between zinc and copper (II) ions) was – 221 kJ mol-1.

13. Answer to questions

1. % error = {[- 221 – (- 217)]/- 217 }x 100% = 1. 84%

The experimental value is more negative than the accepted value.

2. Reasons :

(1) Heat is lost to the surrounding.

(2) The specific heat capacity of the solution is not the same as that of water.

3. CuSO4 is not in excess which is used up totally. No matter that more zinc is used or powder is very finely divided, same amount of the solution is used so there is same increase in temperature.

Thank's for Your Vote!
Enthalpy change of a displacement reaction essay sample. Page 1
Enthalpy change of a displacement reaction essay sample. Page 2
Enthalpy change of a displacement reaction essay sample. Page 3
Enthalpy change of a displacement reaction essay sample. Page 4
Enthalpy change of a displacement reaction essay sample. Page 5
Enthalpy change of a displacement reaction essay sample. Page 6
Enthalpy change of a displacement reaction essay sample. Page 7

This work, titled "Enthalpy change of a displacement reaction essay sample" was written and willingly shared by a fellow student. This sample can be utilized as a research and reference resource to aid in the writing of your own work. Any use of the work that does not include an appropriate citation is banned.

If you are the owner of this work and don’t want it to be published on AssignBuster, request its removal.

Request Removal
Cite this Essay

References

AssignBuster. (2022) 'Enthalpy change of a displacement reaction essay sample'. 27 September.

Reference

AssignBuster. (2022, September 27). Enthalpy change of a displacement reaction essay sample. Retrieved from https://assignbuster.com/enthalpy-change-of-a-displacement-reaction-essay-sample/

References

AssignBuster. 2022. "Enthalpy change of a displacement reaction essay sample." September 27, 2022. https://assignbuster.com/enthalpy-change-of-a-displacement-reaction-essay-sample/.

1. AssignBuster. "Enthalpy change of a displacement reaction essay sample." September 27, 2022. https://assignbuster.com/enthalpy-change-of-a-displacement-reaction-essay-sample/.


Bibliography


AssignBuster. "Enthalpy change of a displacement reaction essay sample." September 27, 2022. https://assignbuster.com/enthalpy-change-of-a-displacement-reaction-essay-sample/.

Work Cited

"Enthalpy change of a displacement reaction essay sample." AssignBuster, 27 Sept. 2022, assignbuster.com/enthalpy-change-of-a-displacement-reaction-essay-sample/.

Get in Touch

Please, let us know if you have any ideas on improving Enthalpy change of a displacement reaction essay sample, or our service. We will be happy to hear what you think: [email protected]