Brain ignite questions that cover the ordinary level syllabus, use these questions to measure how competent you are when it comes to the case of solving chemistry challenges, welcome and get started below
1. Paper chromatography is a method of separating colors or dyes.What two properties should the components of a mixture have that would make the separation possible.
2. A student was asked to prepare Lead (II) chloride salt using the following ingredients; Nitric (V) acid, lead (II) oxide, and hydrochloric acid. Using ionic equations only explains how the salt can be prepared. (2 marks)
3. The nitrates of the following metals were heated strongly and observation was made accordingly. The nitrate of metal P produced the metallic oxide, Nitrogen (IV) oxide, and oxygen gas; and that of metal Q produced the metallic nitrite and oxygen gas. The nitrate of R produced metal R, nitrogen (IV) oxide, and oxygen gas. Arrange the metals in order of reactivity beginning with the most reactive.
4. In an experiment it was found that 40.0cm3 of 0.2M sodium hydroxide solution just neutralized 0.2g of a dibasic acid Q. Calculate the relative molecular mass of acid Q.
5. Give two reasons why during preparation of salt, it is advisable to heat the solution to concentration allowing it to cool in order to crystallize instead of heating to dryness.
6. On complete combustion of a hydrocarbon gas X, 1.32g of carbon (IV) oxide and 0.54g of water. Calculate the empirical formula of X (C = 12.0, H = 1, O = 16.0)
7. Calculate the oxidation number of nitrogen in the following species.
NO2
NH4+
8. In an experiment to determine the relative formula mass of gas P; the time taken for equal volumes of oxygen and gas P under identical conditions of temperature and pressure was measured and the results were shown in the table below. (O = 16.0)
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Gas |
Oxygen |
P |
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Time
in seconds |
20.3 |
30.3 |
9. Using dots and crosses to represent electrons, show bonding in
(a)Sulphur (IV) oxide
(b) Structure of an ion illustrated by the formula N3─
10. Calculate the number of chloride ions in a 250cm3 of 1M solution calcium chloride (Avogadro’s number is 6.0 1023
11. A compound Y reacts with bromine to form another compound, whose formula is:
H Br
CH3 CH2 C C CH3
Br H
What is the formula and name of the compound Y?
12. The grid
below represents part of the periodic table.
Study it and answer the questions that follow. The letters are not the actual symbols.
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Q |
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W |
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Y |
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R |
S |
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T |
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K |
U |
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V |
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Z |
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(a) Hydrogen can be placed in group I or group VII. Explain.
(b) Write the formula of the compound formed between element Y and R.
(c) How does the atomic radii of T and K compare. Explain.
13. Dilute sulphuric (VI) acid reacts with aqueous sodium hydroxide to form a salt. Give the formula and name of the anion in the salt.
14. The molecular formula of a hydrocarbon is C6 H14. The hydrocarbon can be converted into two other hydrocarbons as shown by the equation below.
C6 H14 X + C3 H8
(i) Name and draw the possible structure of formula of x.
(ii) State and explain the observation that would be made if a few drops of bromine water were added to sample of x.
15. The grid below is part of the periodic table.
(The letters do not represent the actual
symbols of the elements). Use the
information to answer the questions that follow.
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A |
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B |
C |
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D |
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E |
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F |
G |
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H |
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I |
J |
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Y |
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b) i) Write the formula of the compound formed when J reacts with B.
ii) Write an equation for the reaction between the compound formed in (i) and water.
c) How does the reactivity of E compared with that of F? Explain.
d) On the grid show by using letter L the first longest period and give a reason why you think it is the first longest period.
e) Write the formula of the ion of F and give the equation of its formation.
16.Explain the following observations:
i) Aluminium utensils should not be cleaned with strongly alkaline washing liquids.
ii) Aluminium alloys are commonly used in aeroplane construction. (1mark)
17. The table below gives some properties of gases D and E
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GASES |
Density |
Effect
of H2SO4(aq) |
Effect
of NaOH(aq) |
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D |
Lighter than air |
Reacts to form a salt
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dissolves without
reacting |
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E |
Heavier than air |
Not affected |
Not affected |
(a) Describe how one would obtain a sample of gas E from a mixture of gases D and E
(b) Suggest a possible identity of gas D
18. Iron roofing sheets are coated with zinc as sacrificial metal;
(i) What is meant by the term ‘sacrificial’?
(ii) Give the name given to the process by which iron sheets are coated with zinc.
(iii) Zinc is higher than iron in reactivity series yet it does not corrode as fast as iron. Explain
19. 400cm3 of Nitrogen gas diffuses through a porous plug in 70 seconds. How long would it take the same volume of Carbon (IV) oxide to diffuse through the same porous pot?
(C=12, O=16, N=14)
20. 20.0cm3 of NaOH solution containing 8.0gdm-3 were required for complete neutralization of 0.118g of a dibasic acid. Calculate the Relative Molecular Mass (R.M.M) of the acid.
(Na=23, O=16, H=1)
21. Briefly describe how you can separate a mixture of copper (II) oxide and potassium chloride into pure separate samples. (3mks)
22. The table below shows results obtained from experiment carried out on a suspect salt solution M.
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Experiment |
Results |
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I.
A few drops of Barium nitrate
added to solution M |
No ppt/ colourless
solution |
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II.
A few drops of lead (II) nitrate
added to solution M. |
White ppt |
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III.
Ammonia solution added dropwise
until in excess |
White precipitate Colourless solution |
(a) Identify the cation and anion present in solution M.
Cation
Anion
b) Write an ionic equation for the formation of white precipitate in experiment II
c) Write the formula of the Ion responsible for formation of colourless solution in experiment III
23. Concentrated magnesium chloride solution is electrolysed using inert electrodes.
a) Name the products formed at
(i) Anode
(ii) Cathode
b) Write the equation of the reaction that occurred at the anode.
24. Study the reaction equation given below.
a) Draw an energy level diagram showing the catalysed and uncatalysed reaction.
b) State the effect on formation of hydrogen bromide if pressure was increased in equation above. Explain.
25. An organic compound has a formula of C4H10O.
a) Write the structural formula of the organic compound.
b) To which homologous series does the compound belong?
c) Name the compound formed when this compound is reacted with propanoic acid.
26. Xcm3 of 0.25M sodium chloride was added to lead (II) Nitrate until in excess, 3.86g of a white precipitate were formed. [Na=23, Pb=207 Cl=35.5 N = 14 O=16]
(i) Write an ionic equation for the formation of white precipitate.
(ii) Work out the value of X.
27. One mole of hydrogen chloride gas was reacted with one mole of ethyne.
(i) Write a balanced equation for the reaction that occurred.
(ii) Name the product formed in 27 (i), above
(iii) Name the product that would be formed when the product named in 27(ii) above undergoes self addition reaction.
Using equations, describe how sulphuric (VI) acid is prepared starting with sulphur (IV) oxide.
28. 5.1g of sodium sulphite was reacted with excess dilute hydrochloric acid. Calculate the volume of the gas collected at room temperature and pressure. (M.G.V = 24000cm3)[Na=23; O=16; S=32]
29. Ammonia reacts with oxygen as shown by the thermochemical equation shown below.
4NH3(g) + 5O2(g) 4 NO(g) + 6H2O(l) ΔH = -1208kJ
a) Work out
(i) Energy evolved when one mole of ammonia reacts with oxygen. (1mk)
(ii) Enthalpy change when 2.4dm3 of ammonia reacts as shown in the equation at s.t.p.
b) Name the catalyst used in this reaction
30. When a current 5A was passed for 19 minutes and 18 seconds through molten metal chloride MCln, 1.04g of metal M were deposited. Work out the formula of metal chloride.
(R.A.M of metal M = 52 1F = 96500c)
31.Equal volume of Nitrogen gas and gas B took 25 seconds and 30 seconds respectively to diffuse through a porous pot under similar conditions. Work out the molar mass of gas B. N=14.)
32. Using dots (.) and crosses (x) to represent electrons. Show the bonding in the compounds formed between
a) Magnesium and chlorine.
b) Silicon and Fluorine chlorine
.jfif)
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