2. A reaction is fast , the time taken for the reaction is short . A reaction is slow , the time taken for the reaction is long . The rate of reaction depends to the speed of reaction . If a reaction is fast, its rate of reaction is high . If a reaction is slow , its rate of reaction is low . The rate of reaction is inversely proportional (berkadar songsang ) with time . Rate ά 1 time taken for reaction Rate of reaction = change in quantity of product / reactant time taken For gas product , rate of reaction = volume of gas time From a graph , the average rate of reaction = the gradient ( kecerunan) of graph

4. Example (b) : The graph below shows the volume of carbon dioxide ,CO 2 released against time for the reaction between calcium carbonate , CaCO 3 and dilute hydrochloric acid, HCl . Determine the rate of reaction at the 20 th second. Rate of reaction at the 20 th second = p q = ( 60 - 30 ) cm 3 ( 40 - 0 ) s = 0.75 cm 3 s - 10 20 30 40 50 60 70 80 10 20 30 40 50 60 Volume of gas / cm 3 Time / s p q P = 60 - 30 Q = 40 - 0 0

8. (e) Mg + 2HCl MgCl 2 + H 2 Mass =? 1 mol of H 2 produced by 1 mol of Mg 0.015 mol of H 2 produced by 0.015 mol of Mg The number of moles of Mg = mass / RAM 0.015 = mass 24 Mass of Mg = 0.015 X 24 = 0.36 g 2 . 6.5 g of zinc powder was mixed with dilute nitric acid , HNO 3 in excess. It was found that it took 50 seconds for all the gas produced to be collected . Calculate the average rate of reaction in cm 3 s -1 . ( Relative atomic mass : Zn ,65 : Molar volume : 24 dm 3 mol -1 at room condition ) Ans : 48 cm 3 s -1

9. CATALYST Temperature CONCENTRATION Pressure Surface Area

10. Size of the particles / Surface area The smaller the size of particles ,the larger the total surface area , the rate of reaction will be higher . Small total surface area Large total surface area CONCENTRATION The higher the concentration of a reactant ,it have more particles per unit volume . The rate of reaction will be higher. A shorter time is required to complete the reaction .

11. Temperature The higher the temperature of the reaction, the particles obtain more kinetic energy . Therefore ,the rate of reaction will be higher . catalyst A catalyst will change the rate of reaction . A catalyst only changes the rate of reaction but not the quantity of products. A catalyst does not undergo any chemical change at the end of the reaction . Pressure Pressure can affect the rate of reaction only if it involves gases. A higher pressure can increase the rate of reaction . The increase of pressure will compress the gas. The particles of a gas will collide more frequently when in a compressed state (smaller volume).

14. Effect of temperature From a graph (a):- A shorter time is needed for sulphur to precipitate at a higher temperature. A longer time is needed for sulphur to precipitate at a lower temperature . From a graph (b) : The rate of reaction will increase when the temperature of the reactant increases . The rate of reaction doubles each time the temperature increases by 10 0 C .

15. Effect of The rate of decomposition of hydrogen peroxide can be increased by increasing the amount of catalyst . The rate of decomposition of hydrogen peroxide decreases with time because the concentration of hydrogen peroxide is decrease when the time increases . Maximum volume of gas in both experiments at the end of the reaction is the same because the volume and concentration of hydrogen peroxide solution used in both experiments are the same . catalyst Hydrogen peroxide H 2 O 2 , decomposes at a faster rate of reaction after the presence of the catalyst ,manganese (IV) oxide, MnO 2 to release oxygen O 2 gas. 2H 2 O 2 2H 2 O + O 2

16. COLLISION THEORY ( TEORI PERLANGGARAN)

17. Collision theory states that before any chemical reactions can occur, particles of the reactants have to collide with each other . Effective collision ---- collision that produces chemical reactions by achieving the minimum energy and correct collision orientation . Colliding particles must have equal or be more than the activation energy ( tenaga pengaktifan ) . Activation energy is the minimum energy needed by the reactant particles to react . Correct collision orientation Effective collision Reaction happens H H I I I I H H I H I H

18. Energy released to its surroundings causes the total energy of the products formed to be lower than the total energy of its reactants. EXOTHERMIC REACTION Release of heat Energy Products reactants Activation energy E a

19. ENDOTHERMIC REACTION Energy is absorbed from its surroundings causes the total energy of the products formed to be higher than the total energy of its reactants Absorption of heat ENERGY PRODUCTS REACTANTS Activation energy E a

27. Ammonia is oxidised to nitrogen monoxide by oxygen. The presence of platinum ( catalyst ). Temperature 850 0 – 900 0 C & pressure 5 atm. 4NH 3 + 5O 2 4NO + 6H 2 0 Nitrogen dioxide is dissolved in water to produce nitric acid . 4NO 2 + O 2 + 2H 2 O 4HNO 3 Nitrogen monoxide is oxidised to nitrogen dioxide 2NO + O 2 2NO 2 Production of Nitric Acid

28. Gas hidrogen dan nitrogen bertindak balas pada suhu 450 0 - 550 0 C , tekanan 200 – 500 atm dan dibantu oleh mangkin ( serbuk ferum ) Bahan penggalak ialah molibdenum N 2 + 3H 2 2NH 3 Production of Ammonia

30. PREPARED BY PN ZAINAB BT AYUB