O Level Science(Chemistry) Examination Preparation for Sec 4
1. Use the Periodic Table to answer this question.
(a)(i) Name the element in Group IV and Period 6 of the Periodic Table.
(ii) State whether the element you have named is a metal, non-metal or metalloid.
(iii) Name the salt that this element can form with chlorine.
(b) Group I elements have similar chemical properties. What is the common characteristic in their atomic structure that contributes to similarities in chemical properties?
2.
(a) What type of oxide do zinc and aluminium form?
(b) Gold, lead and sodium are metals.
(i) Place these metals in order of reactivity, with the most reactive first.
(ii) Write balanced equations sodium and gold each react, if at all, with water.
(iii) Suggest what product is formed when sodium reacts with chlorine gas.
3. Astatine is in Group VII of the Periodic Table.
(a) Predict the colour of astatine.
(b) Is astatine a solid, liquid or gas at room temperature?
(c) Write down the formula of molecular astatine.
(d) What are the products formed when bromine is mixed with potassium astatide? What observations would you expect for the reaction?
4. Iron(III) oxide is reduced to iron in a blast furnace.
(a) Write down the chemical equation for the reaction between slag and calcium oxide.
(b) How is carbon monoxide produced? Write relevant equations for the reactions that take place.
(c) Why is the layer of slag above that of molten iron?
5. A dye, code-name is CCC, is known to contain a few dyes mixed together. Given 4 basic dyes A, B, C and D, filter paper, beakers and alcohol solvent, describe briefly an experiment to find out which dyes does CCC contain.
6. A salt X is analysed to determine its cation and anion. When aqueous ammonia is added dropwise followed by in excess to X, a white precipitate is formed which is soluble in excess aqueous ammonia. When aluminium powder and aqueous sodium hydroxide are added to X and the resultant mixture warmed, a gas that turns moist litmus paper blue is obtained.
(a) Name the gas evolved.
(b) Write down the chemical name of X.
7. How many electrons are shared in the covalent bonds of an ethane molecule?
A 8
B 12
C 14
D 16
8. An element Y forms a negative ion with the electronic structure 2, 8. What is the proton number of Y?
A 10
B 9
C 3
D 2
9. Which two elements combine to form a covalent compound?
A copper and zinc
B sodium and iodine
C carbon and chlorine
D magnesium and chorine
10. Which process is exothermic?
A Photosynthesis
B Melting of ice into water
C Dissolving ammonium nitrate in water
D Iron(II) oxide and nitric acid
11. Why does the decomposition of hydrogen peroxide have the fastest reaction initially?
A The temperature of the reaction mixture is higher initially than at the end of the reaction
B The concentration of the reactant is at its maximum initially
C The catalyst has the greatest catalytic power initially.
D The activation energy is low
12. Octene is an alkene containing eight carbon atoms per molecule. What is its molecular formula?
______________________
13. Write down the molecular formula of the compound that has 4 carbon atoms per molecule which undergoes an addition reaction with liquid bromine.
______________________
14. Which compound is an unsaturated hydrocarbon?
A methane
B propene
C ethanoic acid
D ethanol
15. What carbon containing product is formed when an alcohol reacts with oxygen gas?
A carbon dioxide
B carbonate ion
C carboxylic acid
D alkane
16. Which reagent can be used to distinguish between propane and propene?
A oxygen gas
B aqueous bromine
C potassium iodide
D sodium
17. Which piece of apparatus is most suitable for accurately reacting aqueous sodium hydroxide with 25.0 cm3 of hydrochloric acid which is placed in a conical flask?
A pipette
B burette
C measuring cylinder
D small beaker
18. Which method is to obtain barium sulfate from a mixture of barium sulfate and water?
A crystallization
B filtration
C distillation
D chromatography
19. Which statement about the molecules in the gas carbon monoxide is INCORRECT?
A The gas molecules move at a high speed.
B The gas molecules move randomly.
C The gas molecules have a range of different speeds.
D The gas molecules do not collide with one another.
20. The results of adding some metals X, Y and Z to salt solutions are shown below.
X + copper(II) sulfate à No reaction
Y + zinc sulfate à sulfate of Y + zinc
Z + zinc sulfate à No reaction
Z + copper(II) sulfate à sulfate of Z + copper
What is the order of reactivity of the metals, placed in order of increasing reactivity?
A X, Y, Z, Copper, Zinc
B Y, Copper, X, Zinc, Z
C X, Copper, Zinc, Z, Y
D X, Copper, Z, Zinc, Y
21. A metallic ion in aqueous solution produces a white precipitate with aqueous ammonia, insoluble in excess. The same ion gives a white precipitate with sodium chloride solution. What is the ion?
A aluminium
B lead(II)
C zinc
D ammonium
22. The atoms of element X have the electronic configuration 2, 6.
Which statement about element X is correct?
A It reacts with sodium to form a covalent compound
B It forms an ion of charge 2+
C It has two isotopes only
D It reacts with nitrogen to form a covalent compound
23. An ion of cobalt has 27 protons, 24 electrons and 32 neutrons. What is the charge of the ion?
A 3+
B 2+
C 1+
D 3-
24. The table gives information about four substances.
Which substance has an ionic lattice?
Melting point / oC
Solubility in organic solvent
A 801 Insoluble
B -81 Soluble
C -117 Soluble
D 25 Insoluble
25. In the fermentation of glucose, at which temperature is the reaction the fastest?
A 10oC
B 37oC
C 50oC
D 100oC
26. Zinc is added to an excess of sulfuric acid.
At which point of the reaction is the rate fastest?
A Start of reaction
B 5 minutes after the start
C 15 minutes after the start
D End of reaction
27. Why is potassium stored under oil?
A Potassium can react with water vapour and oxygen in the air
B Potassium can dissolve in oil
C Potassium is unreactive
D Potassium is less dense than water
28. What type of bonding does the product have when the two elements with proton numbers 55 and 53 react together?
A ionic
B covalent
C metallic
D Van der Waals' forces of attraction
Short answers to Exercise 2
1(a)(i) lead
(ii) metal
(iii) lead(II) chloride
(c) Their atoms have one valence electron.
2(a) amphoteric oxides
(b)(i) sodium, lead, gold
(ii) Gold is below hydrogen in the metal reactivity series. It does not react with water.
2Na + 2H2O à 2NaOH + H2 (include state symbols)
(iii sodium chloride (a salt)
3.(a) Black
(b) solid
(c) At2
(d) Displacement reaction. Potassium bromide and Astatine. Dark brown solution formed.
4(a) Slag is silicon dioxide and other impurities.
SiO2 + CaO à CaSiO3
(b) First, carbon reacts with oxygen to form carbon dioxide. Next, carbon dioxide reacts with carbon to form carbon monoxide.
C + O2 à CO2
CO2 + C à 2CO
5. Use paper chromatography to separate out the dyes for CCC. Describe the set-up for paper chromatography according to your textbook. Place CCC, A, B, C and D on the starting line of the filter paper. Use alcohol solvent to run the experiement. Alcohol will dissolve the dyes and the dyes will be carried along the filter paper. Check the dyes that CCC has with A, B, C and D in the paper chromatogram.
6(a) The gas is ammonia gas.
(b) zinc nitrate
7 C
8 B
9 C
10 D
11 B
12 C8H16
13 C4H8
14 B
15 A
16 B
17 B
18 B (barium sulfate is insoluble in water)
19 D
20 D
21 B
22 D
23 A
24 A
25 B (yeast is the catalyst; it is most effective at around 37oC)
26 A
27 A
28 A
(a)(i) Name the element in Group IV and Period 6 of the Periodic Table.
(ii) State whether the element you have named is a metal, non-metal or metalloid.
(iii) Name the salt that this element can form with chlorine.
(b) Group I elements have similar chemical properties. What is the common characteristic in their atomic structure that contributes to similarities in chemical properties?
2.
(a) What type of oxide do zinc and aluminium form?
(b) Gold, lead and sodium are metals.
(i) Place these metals in order of reactivity, with the most reactive first.
(ii) Write balanced equations sodium and gold each react, if at all, with water.
(iii) Suggest what product is formed when sodium reacts with chlorine gas.
3. Astatine is in Group VII of the Periodic Table.
(a) Predict the colour of astatine.
(b) Is astatine a solid, liquid or gas at room temperature?
(c) Write down the formula of molecular astatine.
(d) What are the products formed when bromine is mixed with potassium astatide? What observations would you expect for the reaction?
4. Iron(III) oxide is reduced to iron in a blast furnace.
(a) Write down the chemical equation for the reaction between slag and calcium oxide.
(b) How is carbon monoxide produced? Write relevant equations for the reactions that take place.
(c) Why is the layer of slag above that of molten iron?
5. A dye, code-name is CCC, is known to contain a few dyes mixed together. Given 4 basic dyes A, B, C and D, filter paper, beakers and alcohol solvent, describe briefly an experiment to find out which dyes does CCC contain.
6. A salt X is analysed to determine its cation and anion. When aqueous ammonia is added dropwise followed by in excess to X, a white precipitate is formed which is soluble in excess aqueous ammonia. When aluminium powder and aqueous sodium hydroxide are added to X and the resultant mixture warmed, a gas that turns moist litmus paper blue is obtained.
(a) Name the gas evolved.
(b) Write down the chemical name of X.
7. How many electrons are shared in the covalent bonds of an ethane molecule?
A 8
B 12
C 14
D 16
8. An element Y forms a negative ion with the electronic structure 2, 8. What is the proton number of Y?
A 10
B 9
C 3
D 2
9. Which two elements combine to form a covalent compound?
A copper and zinc
B sodium and iodine
C carbon and chlorine
D magnesium and chorine
10. Which process is exothermic?
A Photosynthesis
B Melting of ice into water
C Dissolving ammonium nitrate in water
D Iron(II) oxide and nitric acid
11. Why does the decomposition of hydrogen peroxide have the fastest reaction initially?
A The temperature of the reaction mixture is higher initially than at the end of the reaction
B The concentration of the reactant is at its maximum initially
C The catalyst has the greatest catalytic power initially.
D The activation energy is low
12. Octene is an alkene containing eight carbon atoms per molecule. What is its molecular formula?
______________________
13. Write down the molecular formula of the compound that has 4 carbon atoms per molecule which undergoes an addition reaction with liquid bromine.
______________________
14. Which compound is an unsaturated hydrocarbon?
A methane
B propene
C ethanoic acid
D ethanol
15. What carbon containing product is formed when an alcohol reacts with oxygen gas?
A carbon dioxide
B carbonate ion
C carboxylic acid
D alkane
16. Which reagent can be used to distinguish between propane and propene?
A oxygen gas
B aqueous bromine
C potassium iodide
D sodium
17. Which piece of apparatus is most suitable for accurately reacting aqueous sodium hydroxide with 25.0 cm3 of hydrochloric acid which is placed in a conical flask?
A pipette
B burette
C measuring cylinder
D small beaker
18. Which method is to obtain barium sulfate from a mixture of barium sulfate and water?
A crystallization
B filtration
C distillation
D chromatography
19. Which statement about the molecules in the gas carbon monoxide is INCORRECT?
A The gas molecules move at a high speed.
B The gas molecules move randomly.
C The gas molecules have a range of different speeds.
D The gas molecules do not collide with one another.
20. The results of adding some metals X, Y and Z to salt solutions are shown below.
X + copper(II) sulfate à No reaction
Y + zinc sulfate à sulfate of Y + zinc
Z + zinc sulfate à No reaction
Z + copper(II) sulfate à sulfate of Z + copper
What is the order of reactivity of the metals, placed in order of increasing reactivity?
A X, Y, Z, Copper, Zinc
B Y, Copper, X, Zinc, Z
C X, Copper, Zinc, Z, Y
D X, Copper, Z, Zinc, Y
21. A metallic ion in aqueous solution produces a white precipitate with aqueous ammonia, insoluble in excess. The same ion gives a white precipitate with sodium chloride solution. What is the ion?
A aluminium
B lead(II)
C zinc
D ammonium
22. The atoms of element X have the electronic configuration 2, 6.
Which statement about element X is correct?
A It reacts with sodium to form a covalent compound
B It forms an ion of charge 2+
C It has two isotopes only
D It reacts with nitrogen to form a covalent compound
23. An ion of cobalt has 27 protons, 24 electrons and 32 neutrons. What is the charge of the ion?
A 3+
B 2+
C 1+
D 3-
24. The table gives information about four substances.
Which substance has an ionic lattice?
Melting point / oC
Solubility in organic solvent
A 801 Insoluble
B -81 Soluble
C -117 Soluble
D 25 Insoluble
25. In the fermentation of glucose, at which temperature is the reaction the fastest?
A 10oC
B 37oC
C 50oC
D 100oC
26. Zinc is added to an excess of sulfuric acid.
At which point of the reaction is the rate fastest?
A Start of reaction
B 5 minutes after the start
C 15 minutes after the start
D End of reaction
27. Why is potassium stored under oil?
A Potassium can react with water vapour and oxygen in the air
B Potassium can dissolve in oil
C Potassium is unreactive
D Potassium is less dense than water
28. What type of bonding does the product have when the two elements with proton numbers 55 and 53 react together?
A ionic
B covalent
C metallic
D Van der Waals' forces of attraction
Short answers to Exercise 2
1(a)(i) lead
(ii) metal
(iii) lead(II) chloride
(c) Their atoms have one valence electron.
2(a) amphoteric oxides
(b)(i) sodium, lead, gold
(ii) Gold is below hydrogen in the metal reactivity series. It does not react with water.
2Na + 2H2O à 2NaOH + H2 (include state symbols)
(iii sodium chloride (a salt)
3.(a) Black
(b) solid
(c) At2
(d) Displacement reaction. Potassium bromide and Astatine. Dark brown solution formed.
4(a) Slag is silicon dioxide and other impurities.
SiO2 + CaO à CaSiO3
(b) First, carbon reacts with oxygen to form carbon dioxide. Next, carbon dioxide reacts with carbon to form carbon monoxide.
C + O2 à CO2
CO2 + C à 2CO
5. Use paper chromatography to separate out the dyes for CCC. Describe the set-up for paper chromatography according to your textbook. Place CCC, A, B, C and D on the starting line of the filter paper. Use alcohol solvent to run the experiement. Alcohol will dissolve the dyes and the dyes will be carried along the filter paper. Check the dyes that CCC has with A, B, C and D in the paper chromatogram.
6(a) The gas is ammonia gas.
(b) zinc nitrate
7 C
8 B
9 C
10 D
11 B
12 C8H16
13 C4H8
14 B
15 A
16 B
17 B
18 B (barium sulfate is insoluble in water)
19 D
20 D
21 B
22 D
23 A
24 A
25 B (yeast is the catalyst; it is most effective at around 37oC)
26 A
27 A
28 A
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