Skema sbp paper 2 essay part c no. 9, 10

1. Skemasbp paper 2essay part cno. 9, 10

2. Essay part c) By using suitable examples, state 2 applications of neutralization in daily life [ 4 marks]

3. Use ammonia to prevent latex from coagulate 2. Use lime /quick lime (calcium oxide)/ slaked lime (calcium hydroxide), chalk (calcium carbonate) to neutralise acidic soil 3. Use magnesium hydroxide / toothpaste to neutralise acid produced by bacteria in our mouth 4. Use antacid /sodium hydrogen carbonate to neutralise acid in stomach of gastric patients

4. Rub bee sting or ant stings ( which is acidic)with calcium carbonate • Rub wasp sting ( which is alkaline ) with vinegar Any 2 applications ( 4 marks)

5. b) By using one named example for each alkali, explain why the pH values of the alkalis are different ( 6 marks)

6. NOTES on pH values and conc of H + ions and OH - ion lower • The higher the conc of H+ ion, the ……..the pH value • So strong acid has a … … pH value than a weak acid of the same concentration lower higher • The higher the conc of OH- ion, the …..the pH value • So strong alkali has a ……. pH value than a weak alkali of the same concentration higher

7. Example of R ; sodium hydroxide solution/ litium hydroxide solution/ potassium hydroxide solution (any strong alkali) R ionised completely in water and produced high concentration of OH- ions Example of Q : ammonia aqueous / solution ( weak alkali) Q ionised partially in water and produce low concentration of OH- ions the higher the concentration of OH – ions in R the higher the pH values

8. Solution X and solution Y are used to prepare barium carbonate saltdescribe the preparation of barium carbonate salt in the laboratory[ 10 marks] Barium carbonate is insoluble salt

9. NOTES – soluble and insoluble salts PCB, PbSO4, CaSO4, BaSO4 All except PAH, PbCl2, AgCl, HgCl2 All except KAN, K2CO3, Na2CO3, (NH4)2CO3 All except All

10. Notes on methods to prepare salts Soluble salts Not KAN salts KAN salts Hot acid + excess solid ( metal/metal oxide/metal hydroxide/metal carbonates) method Titration method Insoluble salts Precipitation or double decomposition

11. notes State which method to use for the preparation of these salts Copper(II) sulphate Hot acid + excess ( copper oxide/ copper(II) hydroxide/ copper(II) carbonate Precipitation Sodium nitrate Titration Silver chloride Barium sulphate Zinc chloride Precipitation Hot acid + excess ( zinc/ zinc oxide/ zinc hydroxide/ zinc carbonate Potassium sulphate Titration

12. TO PREPARE SALT notes SOLUBLE SALT INSOLUBLE SALT KAN SALTS NOT KAN SALTS

13. Pour solution 1 into a beaker solution 1 is barium nitrate solution 50 cm3 of 1.0 moldm-3 Soln 2 is sodium carbonate solution 50 cm3 of 1.0 moldm-3 Add solution 2 into the beaker with solution 1 Stir the mixture using glass rod Filter the mixture Rinse the residue with distilled water Dry the residue in between sheet of filter papers to dry

14. Equation • Ba(NO3) 2 + Na2CO3 BaCO3+ 2NaNO3

15. 10 a)compound A and B burnt completely in oxygen o produce carbon dioxide and water 1- hexene or hex-1-ene • A) name compound B • Why Compound B produce more soot [ 4 marks] % of C in compound B = 6C/ C6H12 =12x6/ 6(12) + 12(1) = 72/84 = 86% % of C in comp A = 6C/ C6H14 =12x6/ 6(12) + 14(1) = 72/86 = 84% % of C in compound B is more than in compound A

16. NOTES Physical properties of organic compound • Ethane or Ethene • Colourlessgas , • low mp and bp, • NOT dissolve in water, • NOT conduct electricity

17. NOTES Physical properties of organic compound • Colourlessliquid • Volatile liquid • low mp and bp, • Miscible in water, • NOT conduct electricity • Ethanol

18. NOTES Physical properties of organic compound • Colourlessliquid • Volatile liquid • low mp and bp, • dissolve in water, • NOT conduct electricity in glacial form, but conduct electricity in aqueous form • Ethanoic acid

19. NOTES Physical properties of organic compound • Colourless liquid, • Sweet smelling • low mp and bp, • volatile liquid, • NOT dissolve in water, • NOT conduct electricity • Floats on water • Less dense than water • Ethyl ethanoate

20. b) State one physical property of compound K. Describe briefly a chemical test to differentiate between compound J and compound K [ 6 marks] • Compound K is ethanol • Miscible in water • Low melting point and boiling point • Does not conduct electricity • Volatile colourless liquid

21. notes Easy chemical test for carbon compounds Add bromine water, brown bromine colourdecolourise • Alkene • Alcohol • Carboxylic acid Add acidified K2Cr2O7 and warm Orange colour change to green Add in a few marble chips, pass the gas through lime water, turns milky

22. Describe briefly a chemical test to differentiate between compound J and compound K [ 6 marks] J is ethanoic acid K is ethanol • Pour 2 cm3 of compound J into a test tube • Add a few drops of acidified potassium dichromate(VI) solution • Warm slowly , Observe colour change • Repeat the procedure above with compound K • If acidified potassium dichromate solution change from orange to green, then the compound is alcohol

23. Describe how to prepare an alkene from a named alcohol through dehydration process. In your description, include the diagram of the apparatus set up and balanced chemical equation for the reaction [ 10 marks]

24. 2. Place glass wool in a boiling tube • 3. Add a few drops of ethanol to the glass wool • 4. Clamp the boiling tube horizontally • 5. Place a porcelain chips in the middle of the boiling tube • 6. Heat the porcelain chips strongly • 7. Heat the ethanol • 8. Collect the gas produced in a test tube • 9. Equation: C2H5OH → C2H4 + H2O

25. homework • 1) complete sbp – paper 3 – all questions for tomorrow at 10 pagi • 2) read up planning experiment- 6 examples with answers • 3) read up essay and answers MARA section B and C