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ALLIANCE HIGH SCHOOL
233/1 - 2018
TIME: 2 HOURS
- A mixture consists of sulphur and iron fillings, the mixture is heated in an open crucible.
- State the observation. (1 mk)
- Write an equation for the reaction. (1 mk)
- Element K (not actual symbol of the element) has isotopes with relative abundance as shown below.
Isotope Relative Abundance (%) 105K 18.69 115K 81.28
Calculate the relative atomic mass of K. (2 mks)
- The table below gives the ionization energies of the alkali metals.
Element 1stionization energy
A 494 B 418 C 519
Which of the three metals is the least reactive. Give a reason. (1 mk)
- Dry hydrogen gas was passed over heated oxide of copper weighing 14.3g, at the end of the experiment 12.7g of copper and 1.8g of water were obtained.
- Determine the formula of the oxide. (Cu - 63.5, O - 16) (2 mks)
- Name two other gases tha can be used instead of hydrogen. (1 mk)
- A piece of burning Magnesium was introduced into a gas jar of nitrogen, water was then added to the products. The resultant solution was tested with litmus paper.
- Explain the observation. (1 mk)
- Write an equation for the formation of the final solution. (1 mk)
- State one reagent that can be used to distinguish between the pairs of ions.
- Pb2+(aq) Al3+(aq) (2 mks)
- SO2-4 and SO2-3 (2 mks)
- 20cm3 of sodium carbonate solution was reacted completely with 25cm3 of a 0.8M hydrochloric acid according to the equations.
Na2CO3 + 2HCl --------> 2NaCl + CO2 + H2O
Calculate the concentrationn of sodium carbonate in grams per litre. (3 mks)
- The electronic arrangement of ions of a certain element represented by letters P Q R and S
- Explain why S is not represented as an ion. (1 mk)
- Which element has the largest atomic radius? Explain. (1 mk)
- A label on a bottle of Hydrochloric acid has the following information;
Density 1.134gm-3 and percentage purity 37%
Determine the molarity of the solution. (4 mks)
- The following figure shows a section of apparatus used in laboratory for measuring volume.
- Identify the apparatus and state the correct reading of volume. (2 mks)
- The atomic number of P and S are 6 and 17 respectively.
- Using dots and cross, draw the compound formed when P reacts with S. (1 mk)
- Name the type of bond and explain whether the compound would conduct electricity. (2 mks)
- A given volume of a gas G diffuses through a membrane in 10 seconds. Under same condition, an equal volume of oxygen diffuses for 12.5 sec. Determine the molecular mass of G. (2 mks)
- Using an equation, explain the observation made when sodium hydroxide is added to Aluminum oxide dropwise until in excess. (2 mks)
- Name the product of the reaction. (1 mk)
- Cynogen is a gaseous compound of carbon and Nitrogen only. On complete combustion in oxygen, 250cm3. Determine the formula of cynogen. (3 mks)
- A stream of Ammonia was bubbled in water containing litums papers.
- State one physical property of the gas. (1 mk)
- Explain the observation made during the experiment. (1 mk)
- A student was given solid potassium permanganate to prepare a colourless gas.
- Draw a complete set up to carry out the experiment naming the gas. (3 mks)
- Propene and propane both decolourises bromine liquid at different conditions.
- Explain with an equation how the hydrocarbons decolourises bromine. (4 mks)
- Complete the reaction by indicating the polymer. (1 mk)
- State type of reaction and calculate the value of n given the molecular mass of polymer is 33600. (4 mks)
- In the apparatus shown in the diagram, compound M and N are reacted to produce Ammonia which is passed to T where it is burnt.
- Name the substance M and N. (2 mks)
- Role of cotton wool and calcium oxide. (1 mk)
- Write an equation for the reaction. (2 mks)
- Below is a chemical reaction.
- Using an energy level diagram, represent the reaction when vanandium(V)oxide is used. (2 mks)
- State the effect of increase in temperature to the equilibrium. (1 mk)
- Give one characterisitc of a dynamic equilibrium. (1 mk)
- Study the test below and answer the questions.
(i) P is heated until no
A colourless liquid
condensed on the cooler
parts of the test tube
-A colourless gas which turns
Aqueous potassium chromate
(VI) green was given out and red
brown residue R was left.
(ii)Chlorine gas was bubbled
through an acqueous of P
Solution turn from green to yellow
- Identify P and R (1 mk)
- Write an equation for test (i) (1 mk)
- Describe how a student would test for anion in solid P. (3 mks)
- Name one reagent that can be used to confirm cation in P. (1 mk)
- Name the main ores of: Iron, copper, sodium, aluminium (2 mks)
- Calculate the oxidation number of P given the following P2O5 (1 mk)
- Identify z and y given the following equation. (3 mks)
- State and explain observation made when chlorine gas is bubbled through a solution of potassium iodide. (2 mks)
- Sketch the bond formed between the complex tetramine copper (II) ions.
- Explain why graphite is used as a lubricant in machines. (3 mks)
- Describe how you would prepare crystals of sodium nitrate starting with 200cm3 of 2M sodium hydroxide. (3 mks)
- One liter of a gas has a mass of 1.16g at s.t.p. Analysis shows that this gas contains 92.3% carbon and 7.69 hydrogen. Calculate the molecular formular of the gas. (C = 12.0, H = 1.0) (2 mks)
- Below is a diagram of a dry cell. Study it and answer the questions that follows.
- Write an equation at anode and cathode. (2 mks)
- Why is Ammonium Chloride used as a paste rather than a dry solid. (1/2 mark)
- Identify the cleansing agent. (1/2 mark)
- Write the molelular formular of the cleansing agent above. (1/2 mark)
- State one advantage of using the cleansing agent. (1/2 mark)
- A student set up the electrochemical cell as represented below.
Pb(s)/Pb(NO3)(l) 1M // SnCl2(aq) (1M)/Sn(s)
- State the condition under which the set up was made. (1 mk)
- Using the Eθ given below, calculate the e.m.f of the cell. (1 mk)
Pb(aq)2+ + 2e- -----> Pb(s) -- 0.13v
Sn(aq)2+ + 2e- -----> Sn(s) -- 0.14v