TERMOKIMIA -ENERGY LEVEL

- Energy Level Diagram is a graph that shows the energy change of a chemical reaction

(graf yang menunjukkan perubahan tenaga dalam tindak balas kimia)

•The energy change can be presented by using anenergy level diagram

.(perubahan tenaga boleh diwakili menggunakan rajah aras tenaga)

lEnergy change, ΔH = energy bond breaking + bond formation

lIn exothermic reaction,

- the heat released from the bond

formation is greater than the heat

absorbed for bond breaking.

- A negative sign for ΔH shows that heat

is released

lIn endothermic reaction,

- the heat absorbed from the bond

breaking is greater than the heat

released for bond forming.

Comments

Proses Pembuatan Sabun

Cleansing Action of Soap Preparation of Soap

Method of Calculating Δ H a ) Quantity of heat change in a substance depends on ( kuantiti perubahan haba bg sesuatu bahan bergantung kepada ): i - Mass of substance (m in grams) ii- Specific heat capacity of a substance (c in Jg -1 o C -1 ) iii- Temperature change ( θ in o C ) b) As chemical reaction occurs in an aqueous solution, assumptions are made during the calculation of heat of reaction : Density of aq solution = Density of water = 1 g cm -3 Density of aq solution = Density of water = 1 g cm -3 Example : - 1 cm 3 of aq solution has a mass of 1 g - 2 cm 3 of aq solution has a mass of 2g Specific heat capacity of solution = Specific heat capacity of water = 4.2 Jg -1 o C -1 The heat of reaction can be calculated by using formula Energy change, H = mc θ Four type of heat of reaction : 1) Heat of precipitation - Heat of precipitation is heat change when 1 mole of precipitate is formed from its ions. 2) Heat of displacement - Heat of displacem

THERMOCHEMISTRY (TERMOKIMIA)

- Termokimia adalah kajian perubahan haba terhadap tindak balas kimia . - Terdapat 2 jenis tindak balas kimia iaitu: Tindak balas Eksotermik - Ekso bermaksud luar manakala termik bermaksud haba. Eksotermik bermaksud haba yang disalurkan/dibebaskan keluar ke persekitaran dalam sistem . Oleh itu suhu di persekitaran akan meningkat. Tindak balas Endotermi k- Endo bermaksud dalam manakala termik bermaksud haba . Endotermik bermaksud haba yang diserap masuk ke dalam dalam bahan hasil tindak balas. Oleh itu suhu bahan tindak balas akan meningkat. Tindak balas eksotermik: Perubahan tenaga tindak balas Eksotermik akan menunjukkan nilai negatif Perubahan Tenaga = Tenaga Hasil Tindak Balas - Tenaga Bahan Tindak Balas ΔH = H h - H b Tindak balas Endotermik Perubahan tenaga tindak balas Endotermik akan menunjukan nilai positif , iaitu Perubahan Tenaga = Tenaga Hasil Tindak Balas - Tenaga Bahan Tindak Balas ΔH = H h - H b VIDEO ANIMASI TERMOKIMIA

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