DISTRICTS SAMPLED AND COMPILED

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DISTRICTS SAMPLED AND COMPILED 1. NDHIWA 2. SOTIK 3. KAKAMEGA CENTRAL 4. NYAMIRA 5. HOMABAY 6. RACHUONYO 7. MIGORI 8. UGENYA/UGUNJA 9. KISUMU WEST 10. MATUNGU 11. BUTERE 12. KAKAMEGA EAST 13. NYATIKE 14.
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DISTRICTS SAMPLED AND COMPILED 1. NDHIWA 2. SOTIK 3. KAKAMEGA CENTRAL 4. NYAMIRA 5. HOMABAY 6. RACHUONYO 7. MIGORI 8. UGENYA/UGUNJA 9. KISUMU WEST 10. MATUNGU 11. BUTERE 12. KAKAMEGA EAST 13. NYATIKE 14. KHWISERO 15. TRANS NZOIA WEST 16. TRANSMARA 17. KAKAMEGA NORTH 18. MUMIAS TOPICS COVERED Questions Answers 1 Introduction to chemistry Simple classification of substances Acids, bases and indicators Air and combustion Water and hydrogen Structure of the atom and the periodic table Chemical families Structure and bonding Slats Effect of an electric current on substance Carbon and its compounds Gas laws The mole 14 Organic chemistry Nitrogen and its compounds Sulphur an dits compounds Chlorine and its compounds Acids, bases and salts Energy changes in chemeical and physical reactions Electrochemistry Metals Organic chemistry II (alkanoic acids an dalakanols) Radioactivity Praticals Introduction to chemistry 1. Wooden splints F and G were placed in different zones of a Bunsen burner flame. The diagram below gives the observations that were made Burnt parts Burnt part G F (a) Explain the difference between F and G (b) Name the type of flame that was used in the above experiment 2. The diagrams below represent a list of apparatus which are commonly used in a chemistry laboratory:- A B C D E (a) Give the correct order of the apparatus, using the letters only, to show the correct arrangement that can be used to prepare and investigate the nature of PH of a sample of onion solution (b) Name one chemical substance and apparatus that is needed in this experiment 3. (a) When the air-hole is fully opened, the bunsen burner produces a non-luminous flame. Explain (b) Draw a labelled diagram of anon-luminous flame 4. (a) What is a drug? (b) Give two drugs that are commonly abused by the youth. 5. The diagram below shows three methods for collecting gases in the laboratory (a) Name the methods A and B (b) From the methods above, identify one that is suitable for collecting sulphur (IV) oxide. Explain 6. A mixture of hexane and water was shaken and left to separate as shown in the diagram below: State the identity of; (i) P.... (ii) W.. 7. The diagrams below are some common laboratory apparatus. Name each apparatus and state its use Diagram Name Use (½mk ) (½mk) 8. The diagram below shows some parts of a Bunsen burner Explain how the parts labelled T and U are suited to their functions T P W U (½mk) (½mk) 9. The diagram below shows the appearance of two pieces of paper placed in different parts of a non-luminous flame of a Bunsen burner and removed quickly before they caught fire. (a) What do the experiments show about the outer region of the flame? (b) From the above experiment, which part of the flame is better to use for heating?give a reason 10. A crystal of copper (II) sulphate was placed in a beaker of water. The beaker was left standing for two days without shaking. State and explain the observations that were made. 11. Study the information in the table below and answer questions that follow. (Letters given are not real symbols) Ions Electron arrangement Ionic radius (nm) A + B + C Explain why the ionic radius of :- (a) B + is greater than that of A + (b) C 2+ is smaller than the of A + Simple classification of substances 1. The diagram below shows the heating curve of a pure substance. Study it and answer the questions that follow: Temperature ( o C) B X C (a) What physical changes are taking place at points X and Z? (b)explain what happens A to the melting point of sodium chloride added to this substance Time 2. (a) State two differences between luminous flame and non-luminous flame (b) It is advisable to set a Bunsen burner to luminous flame prior to an experiment. Explain 3. The paper chromatography of a plant extract gave the following results: Solvent Number of spots X 6 Y 2 Z 3 (a) Which is the most suitable solvent for purifying the extract? Explain (b) Ball pen cannot be used to mark solvent front in the above chromatography. Explain Y D Z 4. Name the process which takes place when: (a) Solid Carbon (Iv) Oxide (dry ice) changes directly into gas (b) A red litmus paper turns white when dropped into chlorine water (c) Propene gas molecules are converted into a giant molecule 5. A sample of copper turnings was found to be contaminated with copper (II) oxide. Describe how a sample of copper metal can be separated from the mixture 6. Copper (II) oxide and charcoal are black solids. How would you distinguish between the two solids? 7. a) What is chromatography? b) Give two applications of chromatography 8. The two elements P and R were separately burned in air, the products gave the results recorded in the table below: ELEMENTS PHYSICAL P SOLID R SOLID STATE AT ROOM TEMPERATURE Physical states of products White solid powder only Colourless gases L and M Nature of solutions in water Basic L strongly acidic M slightly acidic (a) Suggest the identity of element R..... (b) Describe how the nature of the solutions of the of the oxides were determined 9 The diagram below represents a paper chromatography for the three brands of soft drinks containing banned artificial food additives A B C BRANDS OF SOFT DRINKS A and C found to contain the banned artificial food additives. Which numbers indicate the banned artificial food additives? 10. Without using any laboratory chemical, describe a simple laboratory experiment to distinguish between calcium hydrogen carbonate and sodium hydrogen carbonate 11. Substance Q has a melting point of 15 o C and boiling point of 70 o C. (a) On the same axes, draw the melting point and boiling point graph for Q and the room temperature Temperature o C (b) State the physical state of substance Q at room temperature 12. Cooking oils comprise of a mixture of compounds which have a boiling point range Time (minutes) 7 5 3 of 23 o C to 27 o C. (i) What evidence is then to support the statement that cooking oil is a mixture? (ii)name another experimental technique that could be used to confirm your answer in part (i) above 13. A form 1 student carried out the separation as shown in the set-up below:- (i) Identify the method above... (ii) Give one of its disadvantages (iii) Name a mixture which can be separated by the set-up above 14. What is meant by melting point and boiling point of a substance? 15. The apparatus below were used by a student to study the effect of heat on hydrated copper II sulphate (a) What is the role of the ice cold water (b) Name liquid P (c) What observation is made in the boiling tube 17. The diagram below shows chromatograms of blood samples obtained from three athletes. One athlete used illegal drug to improve performance in competition. Drug Substance Water Concentrated Concentrated sulphuric(vi)acid sodium hydroxide Ethene Slightly soluble Soluble Insoluble Ammonia Very soluble Very soluble Very soluble Hydrogen Slightly soluble Insoluble Insoluble (a) Name the line marked M. (b)identify the athlete who used illegal drug Classify the following processes as chemical changes or physical changes Process physical or chemical Neutralization Sublimation Fractional distillation.. Displacement reaction 19. Give two reasons why a luminous flame is not used for heating purposes 20. Classify the following processes as chemical changes or physical changes Process physical or chemical Neutralization Sublimation Fractional distillation.. Displacement reaction 21. Give two reasons why a luminous flame is not used for heating purposes 22. State two criteria for determining the purity of a substance 23. Study the information in the table below and answer the questions. i) A mixture contains ethene, Hydrogen and ammonia gases. Explain how a sample of hydrogen gas can be obtained from this mixture. 24. a)i) The diagram below show spots of a pure substance A, B, and C on a chromatography paper. Spot D is that of a mixture A B C D After development A, B, and C were found to have moved 8cm, 3cm and 6cm respectively. D had separated into two spots which had moved 6cm and 8cm On the diagram above; I. Label the baseline (origin) II. Show the positions of all the spots after development ii) Identify the substances present in mixture D b) Describe how solid ammonium chloride can be separated from a solid mixture of ammonium chloride and anhydrous calcium chloride c) The table below shows liquids that are miscible and those that are immiscible Liquid L 3 L 4 L 1 Miscible Miscible L 2 Miscible Immiscible Use the information given in the table to answer that questions that follow; i) Name the method that can be used to separate L 1 and L 2 from a mixture of the two ii) Describe how a mixture of L 2 and L 4 can be separated 25. A student left some crushed fruit mixture with water for some days. He found the mixture had fermented. He concluded that the mixture was contaminated with water and ethanol with boiling point of 100 o C and 78 o C respectively. The set-up of apparatus below are used to separate the mixture. Thermometer (i) Name the piece of apparatus labelled W (ii) What is the purpose of the thermometer in the set-up? iii) At which end of the apparatus W should tap water be connected? (iv) Which liquid was collected as the first distillate? Explain (v) What is the name given to the above method of separating mixture? (vi) State two applications of the above method of separating mixtures (vi) What properties of the mixture makes it possible for the component to be separated by the above methods? 26. The set-up below was used to separate a mixture:- (a) Name the apparatus missing in the set-up (b) Give one example of mixture T (c) What is the name of this method of separation B Mixture A Distillate Apparatus W Conical flask 27. a) The diagram below shows a set up used by a student to find out what happens when Copper (II) sulphate crystals are heated. Blue copper (II) sulphate crystals (i) State the observations made when the blue copper (II) sulphate crystals are heated. (ii) Identify liquid Y and write an equation for its formation. b) Pellets of sodium hydrogen and anhydrous Copper (II) sulphate were put in separate Petridishes and left in the open for two hours. Explain the observation in each Petri-dish. 28. The chromatography below shows the constituents of a flower extract using an organic solvent:- M Heat Liquid Y Yellow (a) (i) Name a possible organic solvent you can use for this experiment (ii) State one property that makes the red pigment to move the furthest distance from M (iii) Describe how one could get a sample of yellow pigment (iv) On the diagram indicate solvent front (b) Describe how Aluminium chloride can be separated from a mixture of aluminium chloride and sodium chloride 29. Study the information below and answer the questions that follow: Solid Cold water Hot water R Soluble Soluble V Insoluble Insoluble S Insoluble Insoluble Describe how the mixture of solid R, S, and V can be separated 30. Given a mixture of lead (II) oxide, ammonium chloride and sodium chloride, describe how this mixture can be separated to obtain a sample of each. Red Blue Delivery tube Test tube Beaker Ice-cold water 31. The setup below was used to separate two miscible liquids Q and T (Boling points; Q =98 C, T=78 C) (a) Identify the mistakes in the setup above (b)identify Distillate X 32. Name the process which takes place when: a) Solid Carbon (IV) oxide (dry ice) changes directly into gas. b) A red litmus paper turns white when dropped into chlorine water. c) Propene gas molecules are converted into a giant molecule. 33. The following diagram shows a paper chromatogram of substances A, B, C, and D which are coloured (a) Indicate the solvent front on the chromatogram (b) Which substance is pure?.. (c) Substance E is a mixture of C and D. Indicate its chromatogram in the diagram 34. Study the information below and answer the following questions. A mixture contains three solids A, B, and C. The solubility of these solids in different liquids is as shown below:- you will from the A B C D E Solid Water Alcohol Ether A Soluble Insoluble Insoluble B Insoluble Soluble Very soluble C Soluble Soluble Insoluble 35. State and explain the observations made when iodine crystals is heated in a boiling tube? Explain how obtain sample C mixture Acids, bases and combustion 1. The table below shows solutions A, B and C are tested and observations records as shown: Solution Observations on indicator A Methyl orange turns yellow B Phenolphthalein turns colourless C Litmus turns purple (a) Using the table above, name an acid (b) How does the ph value of 1M potassium hydroxide solution compare with that of 1M aqueous ammonia? Explain 2. The information below gives PH values of solutions V, W, X, Y Z Solution PH values V 2 W 6.5 X 11 Y 14 Z 4.5 (a) Which solution is likely to be: (i) Calcium hydroxide?. (ii) Rain water? (b) Which solution would react most vigorously with Zinc carbonate 3. a) Complete the table below to show the colour of the given indicator in acidic and basic solutions. Indicator Colour in Acidic Solution Basic Solution Methyl Orange Yellow Phenolphthalein Colourless b) How does the PH value of 0.1M potassium hydroxide solution compare with that of 0.1M aqueous ammonia? Explain. 4. Use the information given below to answer the questions that follow: Solution G H I J K ph (a) Which of the solutions would be used to relieve a stomach upset caused by indigestion? (b) Which solution is likely to be: (i) Dilute sulphuric acid? (ii) Sodium hydroxide solution? 5. Solid copper (II) oxide is a base although it does not turn litmus paper to blue. Explain 6. Below are the ph values of 4 types of medicine represented by letters P, Q, R and S MEDICINE ph VALUES P 7.0 Q 5.0 R 8.0 S 6.0 a) It is not advisable to use S when a patient has indigestion.explain b) What is the role of chemistry in drug manufacture 7. Explain why very little Carbon (IV) oxide gas is evolved when dilute sulphuric (VI) acid is added to lead (II) carbonate 8. State one commercial use of Calcium Oxide 9. The following data gives the ph values of some solutions Solution P Q R ph (a) What colour change would occur in solution P on addition of two drops of phenolphthalein indicator? (b) State the ph value of a resulting solution when equal moles of solution P and R react 10. In an experiment, ammonia gas was prepared by heating ammonium salt with an alkali. After drying, ammonia gas was collected at room temperature and pressure. (a) What is meant by the term alkali? (b) Explain using physical properties of the gas why ammonia is not collected by downward delivery 11. The table shows the colours obtained when some indicators are added to solutions:- Solution Blue litmus paper Indicator W Distilled water.. Colourless Calcium hydroxide Blue Pink Nitric acid Colourless (a) Complete the table by filling in the missing colours (b) Identify indicator W 12. (a) Flower extracts can be used as Acid-base indicators. Give two limitations of such indicators (b) The diagram below shows spots of pure substances W, X, and Y on a chromatography paper. Spot Z is that of a mixture W X Y Z After development W, X, and Y were found to have moved 9cm 3, 4cm 3 and 7cm 3 respectively. Z has separated into two spots which have moved 7cm 3 and 9cm 3 :- On the diagram:- I. Label the baseline and solvent front II. Show the position of all the spots after development III. Identify the substances present in mixture Z 13. A beekeeper found that when stung by a bee, application of a little solution of sodium hydrogen carbonate helped to relieve the irritation of the affected area. Explain g of sodium hydrogen carbonate were dissolved in 20cm 3 of water in a boiling tube. Lemon juice was then added dropwise with shaking until there was no further change. (a) Explain the observation which was made in the boiling tube when the reaction was in progress (b) What observations would be made if the lemon juice had been added to copper turnings in a boiling tube? 15. (a) Complete the table below to show the colour of the given indicator in acidic and basic solutions: Indicator Colour in acidic solution Basic solution Methyl orange Pink Phenolphthalein Pink 16. Solutions can be classified as acids, bases or neutral. The table below shows solutions and their ph values:- (i) Select any pair solution of PH 7 (ii) Identify two aluminium hydroxide. Explain Air and combustion Solutions K L M PH VALUES that would react to form a 1. The set-up below was used to prepare a sample of oxygen gas. Study it and answer the questions that follow. solutions that would react with H 2 O 2 (i) Complete the diagram to show how Oxygen can be collected (ii) Write a chemical equation of the reaction to produce oxygen MnO 2 2. Air was passed through several reagents as shown below: Concentrated sodium hydroxide Excess copper Air solution turnings hydroxide solution Escaping gases Excess heated magnesium powder (a) Write an equation for the reaction which takes place in the chamber containing Magnesium powder (b) Name one gas which escapes from the chamber containing magnesium powder. Give a reason for your answer 3. (a) What is rust? (b) Give two methods that can be used to prevent rusting (c) Name one substance which speeds up the rusting process g of clean magnesium ribbon 8.0g of clean copper metal were burnt separately in equal volume of air and both metals reacted completely with air; a) State and explain where there was greater change in volume of air Mg =24 Cu = 64 b) Write an equation for the reaction between dilute sulphuric acid and product of burnt copper 5. Oxygen is obtained on large scale by the fractional distillation of air as shown on the flow chart bellow. a) Identify the substance that is removed at the filtration stage b) Explain why Carbon (IV) oxide and water are removed before liquefaction of air c) Identify the component that is collected at -186 C 6. The set-up below was used to study some properties of air. Moist iron wool State and explain two observations that would be made at the end of the experiment 7. A form two student in an attempt to stop rusting put copper and Zinc in contact with iron as shown:- Copper Water (i) Iron Zinc (a) State whether rusting occurred after one week if the set-ups were left out (b) Explain your answer in (a) above (ii) Test tube Beaker 8. In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4g of the clean magnesium ribbon was placed in a crucible and completely burnt in oxygen. After cooling the product weighed 4.0g a) Explain why it is necessary to clean magnesium ribbon b) What observation was made in the crucible after burning magnesium ribbon? c) Why was there an increase in mass? d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the observation which was made when red and blue litmus paper were dropped into the filtrate 9. In an experiment a gas jar containing some damp iron fillings was inverted in a water trough containing some water as shown in the diagram below. The set-up was left un-disturbed for three days. Study it and answer the questions that follow: Damp iron fillings Water Inverted gas jar Water Trough (a) Why were the iron filings moistened? b) State and explain the observation made after three days. (c) State two conclusions made from the experiment. d) Draw a labelled set-up of apparatus for the laboratory preparation of oxygen using Sodium Peroxide (e) State two uses of oxygen 10. In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4g of the clean magnesium ribbon was placed in a crucible and completely burnt in oxygen. After cooling the product weighed 4.0g a) Explain why it is necessary to clean magnesium ribbon b) What observation was made in the crucible after burning magnesium ribbon? c) Why was there an increase in mass? d) Write an equation for the major chemica
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