Page 42 - Hybrid PBD 2022 Tg 5 - Kimia

Kimia Tingkatan 5 Bab 3

3. Tentukan perubahan suhu dalam jadual keputusan di atas.
Determine the temperature changes in the table of result above.
4. Lengkapkan jadual di bawah.
Complete the table below.
[muatan haba tentu air, c = 4.2 J kg °C ]
–1
–1
–1
–1
[specific heat capacity of water, c = 4.2 J kg °C ]
Campuran bahan Larutan ammonia dan asid Larutan ammonia dan asid etanoik
tindak balas hidroklorik Ammonia solution and ethanoic acid
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Reacting mixtures Ammonia solution and hydrochloric acid
Bilangan mol asid 1.0 × 50 = 0.05 mol 1.0 × 50 = 0.05 mol
Number of moles of acid 1000 1000

Perubahan haba = mcθ (50 + 50) × 4.2 × 5.8 J = 2436 J (50 + 50) × 4.2 × 5.0 J = 2100 J
Heat change
Persamaan kimia NH 4 OH + CH 3 COOH →
Chemical equation NH 4 OH + HCl → NH 4 Cl + H 2 O CH 3 COONH 4 + H 2 O
Haba peneutralan 1 mol HCl : 1 mol H 2 O 1 mol CH 3 COOH : 1 mol H 2 O
Heat of neutralisation 0.05 mol : 0.05 mol 0.05 mol : 0.05 mol
2436 2100
ΔH = = −48720 J mol ΔH = = −42000 J mol
−1
−1
0.05 0.05
// −48.72 kJ mol −1 // −42.00 kJ mol −1
5. Lukis gambar rajah aras tenaga bagi tindak balas peneutralan.
Draw the energy level diagram for the neutralisation reactions.

Gambar rajah aras tenaga bagi tindak balas NaOH + HCI
antara natrium hidroksida dengan asid Tenaga ΔH= –57.12 kJ mol –1
hidroklorik Energy
Energy level diagram of the reaction between sodium NaCI + H O
2
hydroxide and hydrochloric acid
Gambar rajah aras tenaga bagi tindak balas NaOH + CH COOH
3
antara natrium hidroksida dengan asid Tenaga ΔH= –50.40 kJ mol –1
Energy
etanoik CH COONa + H O
Energy level diagram of the reaction between 3 2

6. Adakah terdapat pengaruh kekuatan asid dan alkali terhadap nilai haba peneutralan?
Wajarkan jawapan anda.
Is there an influence of acid and alkali strengths on the value of heat of neutralisation? Justify your answer.

Ya. Daripada eksperimen, nilai haba peneutralan adalah paling rendah bagi tindak balas antara
larutan ammonia dengan asid etanoik. Larutan ammonia adalah alkali lemah dan asid etanoik
adalah asid lemah. Asid lemah dan alkali lemah mengion separa di dalam air, maka sebahagian haba

diserap untuk mengionkan molekul asid lemah dan alkali lemah. / Yes, it is. From the experiment, the value of
heat of neutralisation is the lowest for the reaction between ammonia solution and ethanoic acid. Ammonia solution is a weak
alkali and ethanoic acid is a weak acid. Weak acid and weak alkali ionise partially in water, so some of the heat is absorbed to
ionise the molecules of weak acid and weak alkali.

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03 Hybrid Kimia Tg5.indd 113 05/11/2021 4:18 PM