Question Library

(a)(i) Give two differences between a conductor and an electrolyte. (ii) State three applications of electrolysis. (iii) Write equation for the reaction at each electrode when a dilute solution of sodium chloride is electrolysed using carbon electrodes. (b)(i) What is an electrochemical cell? (ii) Give two examples of primary cells. (iii) Split the following equation into two balanced hall cell equations. Mte + Fe\(^{2+} \to Mg^{2+} + Fe\). (c)(i) A current of 0.72 amperes was passed through dilute tetraoxosulphate (VI) acid for 3 hours 20 minutes. Calculate the quantity of electricity that was passed (ii) If 1 dm\(^3\) of gas evolved at the cathode during the electrolysis of acidified water, what was the volume of gas evolved at the anode? (d)(i) 20g of copper(II) oxide was warmed with 0.05 mole of tetraoxosulphate (VI) acid. Calculate the mass of copper (II) oxide that was in excess. The equation for the reaction: CuO\(_{(s)}\) + H\(_2\)SO\(_{4(aq)}\) ---> CuSO\(_{4(aq)}\) + H\(_2\)O\(_l\) [0 = 16 ; Cu = 64] (ii) What type of reaction was involved in (d)(i)?

(a)(i) Define allotropy. (ii) Name the allotrope of carbon used in gas masks. (iii) Mention two other elements which exhibit allotropy apart from carbon. (b) List the products of each of the following reactions: (i) Heating coal in the absence of air. (ii) Burning of candle wax in plentiful supply of air (c)(i) State the two properties of carbon (IV) oxide which make it useful in extinguishing fire. (ii) Write an equation for the reaction of carbon (IV) oxide with lime water (iii) Calculate the volume of oxygen that was in excess if 150cm\(^3\) of carbon (II) oxide was burnt in 80cm\(^3\) of oxygen according to the following equation: 2CO\(_{(g)}\) + O\(_{2(g)}\) \(\to\) 2CO\(_{2(g)}\). (d)(i) State how nitrogen can be obtained from ammonia gas. (ii) Name the gaseous fuels obtained when steam and air are passed over red hot coke. (iii) Which of the fuels in (d)(ii) has the lower heating ability? Give reason for your answer.

(a)(i) List two elements which react with steam at red heat to produce hydrogen. (ii) Explain why an aqueous solution of potassium bromide turned reddish brown on bubbling chlorine through it. (iii) Write an equation for the reaction in (a)(ii). (b)(i) Name two types of chemical industry that use limestone as raw material. (ii) Give one example of hygroscopic substances. (iii) Copy and complete the table below. Salt to be prepared Starting material Method of preparation PbSO\(4\) Pb(NO\(_3)_{2(ag)}\) - KNO\(_3\) KOH Neutralization CaCl\(_2\) CaCO\(_3\) - FeCl\(_3\) Fe\(_(s)}\) - CuSO\(_4\) CuO - (c) In the contact process for the manufacture of tetraoxosulphate (VI) acid; (i) State how sulphur (IV) oxide is obtained; (ii) Write an equation for the reaction that takes place in the catalyst chamber; (iii) Give the steps required to convert sulphur (VI) oxide to acid. (d)(i) List two disadvantages of hard water. (ii) Mention three methods which can be used to remove both permanent and temporary hardness in water at the same time. (iii) State the role of alum and chlorine respectively in the purification of water for town supply.

(a) List two gases in each case which; (i) can be used to demonstrate the fountain experiment; (ii) decolourize acidified potassium tetraoxomanganate (VII). (b) State briefly how you would distinguish between (i) crystals of PbCO\(_3\) and Pb(NO\(_3\)) using heat; (ii) solutions of NH\(_4\)CI and NaCl using litmus paper. (c) Mention two changes that would be observed on adding moderately concentrated hydrochloric acid to iron filings

Credit will be given for strict adherence to instructions, for observations precisely recorded and for accurate inferences. All tests observations and inferences must be clearly entered in your answer book. in ink, at the time they are made. C is a mixture of two inorganic compounds. Carry out the following exercises on C. Record your observations and identify any gases evolved. State the conclusion you draw from the result of each test. (a) put all of C into a beaker and add about 10cm\(^3\) of distilled water. Stir thoroughly and filter. Keep both the residue and the filtrate (b) Divide the filtrate into three portions. (i) To the first portion, add sodium hydroxide solution in drops until ít is in excess. (ii) To the second portion, add aqueous ammonia in drops until it is in excess. (iii) To the third portion, add about 2cm\(^3\) of barium chloride solution, followed dilute hydrochloric acid in excess. (c) Put the residue in a test tube and add about 2cm\(^3\) of dilute tetraoxosulphate (VI) acid. Shake the mixture and warm. (i) Add aqueous ammonia in drops to the mixture from (c) (i) above until it is in excess.

All your burette readings (initial and final), as well as the size of your pipette, must be recorded but on no account of experimental procedure is required. All calculations must be done in your answer book. (a) Put A into the burette and titrate it against 20.0 cm\(^3\) or 25.0 cm\(^3\) portion of B using methyl orange as indicator. Record the volume of your pipette. Tabulate your burette readings and calculate the average volume of A used. The equation for the reaction is 2NaOH\(_{(aq)}\) + H\(_2\)X\(_{(aq)}\) \(\to\) 2H\(_2\)O\(_{(l)}\) (b) From your results and the information provided, calculate the; (i) Concentration of solution B in mol dm\(^{-3}\) (ii) concentration of solution A in mol dm\(^{-3}\) (iii) molar mass of the acid H\(_2\)X. [H = 1, O = 16, Na = 23]

Select the correct option for the space numbered 25 in the above passage

Read the following carefully and answer the questions on it. In all school systems of the world, some schools are considered 'better' than others. In fact, based on such a judgment parents often go to great lengths to have their children enrolled in one school rather than another. One yardstick for Furthermore, making this judgment is student achievement, especially general performance in public examinations. _ among some experts in education, opinions about schools are further narrowed down to subject areas. For example, one often hears that school A is better than B in Mathematics and Science while the latter is better than the former in English Language and the Liberal Arts. Whatever the focus of these comparative statements, there remains the fact that schools do vary in terms of average student achievement. Why is it then that some schools have high average student achievement while others have low average student achievement? The reasons are not far-fetched. The first reason is that some schools are located in privileged areas in the sense that the students come from homes where parents care about their children's education ensure that the children are well-fed, show interest in their school work and provide easy access to books in the home. On the other hand, there are schools which serve less privileged communities, and whose students come from homes where parents are unable to provide the necessary support services for good academic work. Students in the first type of school would generally have a higher rate of achievement than those in the second type. Another reason for the difference in academic achievement between schools is how well the schools are equipped. Schools that have good laboratories and libraries, ample space. places to sit and write for every student and optimum-sized classrooms usually record a higher standard of student achievement than those where the basic equipment is lacking or where the students are crammed into inadequate spaces. The quality of the teachers also has to do with the differences in student achievement between schools. A teacher that does not have a good grasp of his subject matter nor is committed to his job cannot produce an outstanding student. On the other hand students will generally attain a high standard where the teacher is an expert in his field, knows how to structure the material to be learned, demands a lot from his students and motivates them. Also, school management has been found to have a relationship with student achievement. Students perform better in schools where the leadership is enthusiastic and creative than in schools where the principals and teachers adopt a casual attitude to their job. Finally, discipline cannot be divorced from the learning process, and this is often seen from the perspective of general student behaviour. Where students show a disregard for the rules and regulations that guide good learning by disobeying their teachers, neglecting their homework or playing truant, they cannot make any reasonable academic progress. On the other hand, students who comport themselves well have laid a good foundation for academic success. (a) In one sentence, summarize the yardsticks used to make a distinction between one school and another. (b) In five sentences, one for each. summarize the factors responsible for the different levels of achievement in schools.

You are in the final year in secondary school. Write a letter to your uncle, who is an influential person in the society, telling him what you intend to do next and asking for his assistance.

You have just returned to the city from your village where you spent the last holiday. In an article suitable for publication in your school magazine, compare life in your village with that in the city.

There was a riot in your school resulting in extensive damage and the Ministry of Education ordered your school to be shut down. Write a letter to the Commissioner for Education, explaining the causes of the disturbance and appealing for the school to be re-opened.

As your contribution to a debate, write arguments for or against the proposition. "We are happier than our fore fathers".

Narrate an experience you have had or heard about that illustrates the saying: "Where there is a will there is a way"

Read the following passage carefully and answer the questions on it. One of the puzzles to which I had no solution as a child was how my cousin could seal an envelope with his saliva. Each time he wrote a letter for my illiterate father, he merely ran his tongue over the inner edge of the flap of the envelope, folded it and then sealed it. Just like that! In my puzzlement, I tried the same trick repeatedly with two pieces of paper but my saliva failed to hold them together. I then theorized that my cousin's saliva must be gummy. If that was so, why wasn't mine? My studied search for a solution led to the very sound conclusion that my cousin's saliva was gummy because he was the only educated man in the family. By extension. I reasoned that all educated people had sticky saliva. But it didn't take me long to wonder why my cousin's lower jaw was not stuck to the upper jaw. Indeed. I wondered how morsels of food could roll down to his gullet without sticking to the tongue and the palate. Each time I was around when he ate, I watched him put one morsel after another into his mouth without experiencing any problem in getting it down. After many days, indeed weeks, of pondering over this thorny issue. I decided that while all educated men had sticky saliva, they had developed a special mechanism for neutralizing the stickiness when eating. My theory received a severe jolt one day when father had to get a letter written but my cousin was not around. Father sent to the next house for his niece. the nearest educated person around. After the lady had written the letter, father brought out an old envelope which had probably been lying forgotten for months on his cupboard. But, to my amazement, the flap would not stick well to the body of the envelope, no matter how many times she applied her saliva. In the end, father used some pap as gum. With this. my new puzzle was: "Why was the educated man's saliva sticky while the educated woman's saliva was not?" Before long, I decided that the woman's saliva was not so sticky because she was not as learned as the man. So, I updated my theory: the more learned a person was, the more gummy his saliva would be. Fine theory. The death knell sounded on my latest theory one day when father sent me to buy an envelope from a nearby shop. Having bought it, I studied its flap closely and discovered that its inner edge had some glossy material. It felt sticky to my touch. Curious, I ran my tongue over it and I sealed the envelope. That was it! It got stuck, refusing to be parted no matter how much I tried. When I delivered it that way. father rightly guessed that I had tampered with it Although I received a spanking. I was consoled that at last, I had unravelled the mystery. (a) State the writer's original theory. (b) State the modification to the original theory. (c) What incident gave rise to the modification of the theory? (d) Why didn't the flap stick to the envelope when the woman tried to seal it? (e) What lesson did the writer finally learn? (f) "The death knell sounded on my latest theory" (i) What type of figurative expression is this? (ii) What does it mean? (g) "... which had probably been lying forgotten for months on his cupboard." (i) What grammatical name is given to this expression? (ii) What is its function as it is used in the sentence? (h) For each of the following words. find another word or phrase that means the same and can replace it as it is used in the passage: (i) puzzlement (ii) thorny (iii) severe (iv) theory (v) unraveled

Read the following passage carefully and answer the questions on it. The black ant is indisputably one of the smallest visible insects on earth Except with aid of a very powerful microscope, it is difficult if not impossible to locate the eyes, the mouth the nostrils (if it ever has any) or any other part of the body. An air of mystery surrounds the existence of this little creature. Have you ever taken time off your programme to watch these ants move in row? What gives them the sense of direction, we do not know. Indeed whoever sends them on an errand and how they even know their destination and the type of errand to run we are yet to be told. But they are an extremely well-organized lot. Certainly, there are no defined routes for them on walls or trees, yet they move in an orderly manner. almost in a straight line. The beautiful thing about these insects is that even when their line of movement is disorganized. they soon regroup and connect themselves again end to end. If in the process. one of them is killed. they quickly recognize that fact from their various positions. Then. one sees them running helter skelter with a seeming insistence on getting at the comrade to confirm its death. When this has been done, some of them run zigzag at a tremendous speed to alert the others on the route. Soon, they disappear completely. Later. as if everything were over and forgotten they reappear and form a new route and continue their movement transporting food or going on one errand or the other as before Bring your ears close to them and you hear nothing and you wonder what their means of communication could be. Perhaps, most surprising is their high sense of understanding the weather and the climate They are just like men in this area. They know when it is the rainy season and when the dry season comes. In fact, it is true to say that they prepare better for the future than man. During the dry season. they file out to different places gathering food which they store underground. At the slightest sign of the approach of the rainy season. they all get into the hole and seal it up. Surprisingly. they re-emerge when the dry season sets in. And whoever tells them that the dry season has come we do not know. You can now see the sense in the injunction, "Go to the ant, thou sluggard. learn her ways and be wise." (a) Why does the writer regard the black ant as one of the smallest insects on earth? (b) Give reasons why the writer thinks that the way ants live is ' interesting'? (c) (i) What is the writer's attitude towards the black ant? (ii) Quote an expression from the passage to support your answer. (d) When this has been done " What does 'this' refer to? (e) "The beautiful thing about these insects ..." (i) What grammatical name is given to this expression (ii) What is its function in the sentence? (f)What quality of the wins implied in the last sentence of the passage? (g) For each of the following words or phrases find another word or phrase that means the same and can replace it as it is used in the passage: (i) indisputably; (ii) row; (iii) helter skelter, (iv) a tremendous (v) area (vi) approach.