Name:
1.
Revision Short Questions(5)
Class no:
Which of the following compounds has the lowest boiling point? Why?
Ethanol
propan-1-ol
propane
butane
Propane. The molecules in ethanol and propan-1-ol are held together by intermolecular hydrogen bonds which is stronger
than Van der Waals forces among propane and butane. The molecular mass of propane is smaller than butane. So the Van
der Waals’ forces in propane is weaker than that in butane.
2.
25.0 cm3 of an acid with concentration 1.0M require 37.5 cm3 of 2.0M sodium hydroxide for complete neutralization. What
is the basicity of that acid?
Let n be the basisity of the acid , then
no. of mole of acid
:
H nA +
no. of mole of NaOH =
─→
nNaOH
0.025
NanA +
: 0.075 mol
=
1:3
nH2O
so n = 3
So the basicity of the acid = 3
3.
Complete the following table
Product formed when reacted with dilute
Product formed when reacted with concentrated
sulphuric acid
sulphuric acid
Zinc
4.
Hydrogen
+
zinc sulphate
Sulphur dioxide
Cane sugar
No reaction
Carbon
+
water
Ammonia
Ammonium sulphate
Ammonium sulphate
Copper(II) sulphate
crystal
No reaction
White ppt of anhydrous copper(II) sulphate
Iron can be extracted from iron(III) oxide by the following reaction:
Fe2O3(s) + 3CO(g)

2Fe(s) + 3CO2(g)
What mass of iron(III) oxide is required to produce 2.1g iron?
(R.A.M. :
O = 16.0，Fe = 56.0)
no. of mole of 2.1 g Fe =
2.1
 0.0375 mol
56
no. of mole of Fe2O3 required =
0.0375
 0.01875mol
2
mass of Fe2O3 required = (56×2+16×3)×0.01875=3.0g
5.
The table below shows the electrical conductivity of four substances W、X、Y and Z：
(: conduct electricity ;  : cannot conduct electricity)
Substance
W
X
Y
Z
Solid state




Liquid state




Which one would be zinc chloride? W
Which one would be a metal?
Z
Aqueous solution



(insoluble in water)
Which one would be glucose?
Y
6.
State the colour of the following ions:
Ni2+
7.
green
Fe3+
Cr3+
yellow
green
Potassium permanganate is a common oxidizing agent which is usually acidified by dilute sulphuric acid.
(a)
Dilute nitric acid is not used to acidify permanganate. Why?
Dilute nitric acid is also an oxidizing agent that
may compete with permanganate to react with the reducing agent.
(b)
Dilute hydrochloric acid is not used to acidify permanganate. Why?
HCl will be oxidized by permanganate to
form chlorine gas.
(c)
Dilute ethanoic acid is not used to acidify permanganate. Why?
Ethanoic acid is a weak acid. The concentration
of H+ is not high enough to acidify permanganate.
8.
If 8.0 g of oxygen and 20.0 g of gas X occupy the same volume at room temperature and pressure, what is the molar mass
of X?
(R.A.M.: O = 16.0； Molar mass of gas at R.T.P.
= 24.0 dm3)
Since they occupy the same volume, so no. of mole of O 2 = no. of mole of X
So
8.0/16x2
=
20.0 / molar mass of X
Molar mass of X = 80 g mol-1
9.
The percentage by mass of X in compound X2S is 58.9%. What is the relative mass of X? (R.A.M.: S = 32.1)
Let x be the relative atomic mass of X,
10.
2x
 100%  58.9% ， thus x = 23
2 x  32.1
Complete the table below:
What gaseous product will be formed?
Adding calcium to water
hydrogen
Adding magnesium to dilute
hydrogen
hydrochloric acid
Adding copper to dilute nitric acid
Passing steam to hot iron
11.
Nitrogen monoxide
Hydrogen
Will precipitate form when sodium hydroxide solution mixes with the each of the following solutions? If precipitate will
be formed, state its colour.
ppt formed﹖colour of the ppt﹖
Lead(II) nitrate solution
Yes. White ppt
Iron(III) nitrate solution
Yes. Brown ppt
Copper(II) nitrate solution
Yes. Blue ppt
Potassium nitrate solution
No ppt
12.
13.
Balance the following equation:
2HNO3 + xFeSO4 + yH2SO4

zFe2(SO4)3 + 4H2O + 2NO
2HNO3 + 6FeSO4 + 3H2SO4

3Fe2(SO4)3 + 4H2O + 2NO
In an experiment, iodine was put in potassium iodide solution. Sulphur dioxide was then passed through the solution.
(a)
What would be the observable change?
The solution would change from brown to colourless.
(b)
Write an equation for the reaction occur.
SO2
+
I2 +
2 H2O
H2SO4
+
2 HI
14. In an experiment, 1.00M sodium hydroxide solution was added to 25.0 cm3 1.00M sulphuric acid until the acid was just
completely neutralized. What would be the concentration of sodium sulphate in the resulting solution?
2NaOH
+
H2SO4
Na2SO4
no. of mole of H2SO4 = 0.025 mol,
+
2 H2O
no. of mole of NaOH needed = 0.050 mol, vol. of NaOH needed = 50 cm3.
No. of mole of Na2SO4 formed = 0.025 mole.
Volume of the resulting solution = 25+50 = 75 cm 3
Concentration of Na2SO4 = 0.025 / 0.075 = 0.33 M
15.
Concentrated sulphuric acid and anti-bumping granules were added to a mixture of an alkanoic acid and a alkanol. The
following compound was formed after heating the mixture under reflux.
H
O
H C
O C
H
16.
H H
C C H
H H
(a)
The alkanoic acid is:
propanoic acid
The alkanol is:
methanol
(b)
What is the function of concentrated sulphuric acid?
It acts as a catalyst.
(c)
What is the purpose of adding anti-bumping granules?
To prevent uneven boiling of the solution.
(d)
What is the purpose of heating under reflux?
(e)
Draw the experiment set-up used for heating under reflux.
To prevent loss of reactants or products.
Complete the table below
Polymer
Is it a thermoplastic?
Is it a condensation polymer?
nylon
Yes
Yes
perspex
Yes
No
polyethene
Yes
No
Urea methanal
No
Yes
17.
(a)
What is the active ingredient in household bleach?
Sodium hypochlorite
(b)
How to make household bleach?
Passing chlorine to sodium hydroxide solution.
(c)
Sodium chloride is the raw material used to make household bleach. Why?
It is because chlorine and sodium
hydroxide are the products of electrolysis of concentrated sodium chloride solution
(d)
18.
Is household bleach acidic or alkaline?
Alkaline
What is the bad effect of the each of the following pollutants.
pollutant
19.
A.
hydrocarbon
carcinogenic
B.
carbon monoxide
C.
lead compound
damage the nervous system
D.
carbon particulates
carcinogenic
decrease the oxygen carrying capacity of blood
Can each of the following metal oxide be reduced by heating with carbon?
(1)
20.
bad effect
Magnesium oxide
No
lead(II) oxide
yes
iron(III) oxide
yes
What is the product formed when each of the following compounds reacts with acidified potassium permanganate
solution?
(1)
(3)
21.
23.
ethan-1,2-diol
iron(II) sulphate solution
ethanol
ethanoic acid
iron(III) sulphate solution
Is iodine a substance with giant covalent structure?
No
(b)
Give two substances that have giant covalent structure.
(c)
Every two iodine atoms are held together by covalent bond to form a molecule. Is it correct?
Diamond,
quartz
Yes
(a)
What hazard warning label(s) should be put on the container containing potassium?
(b)
What hazard warning label(s) should be put on the container containing methanol? flammable and toxic
flammable
The reaction of chlorine and hot concentrated potassium hydroxide solution can be represented by the following equation:
3Cl2(g) + 6KOH(aq) 
(a)
24.
(2)
Iodine is a solid at room temperature and pressure.
(a)
22.
ethene
5KCl(aq) + KClO3(aq) + 3H2O(l)
What is the change in oxidation number of chlorine? From 0 to －1 and from 0 to +5。
(b)
What is the oxidizing agent? Why? Chlorine. It is because its O.N. decreases from 0 to –1
(c)
What is the reducing agent? Why? Chlorine. It is because its O.N. increases from 0 to +5.
Name 5 substances that should be kept in brown reagent bottles.
(a)
nitric acid
(d)
chlorine water / bleach
(b)
silver nitrate
(e)
potassium permanganate
(c)
bromine water
25.
The structure of polymer X is:
H Cl H Cl H Cl H Cl
...
C C C C C C C C
...
Cl H Cl H Cl H Cl H
(a)
What is the monomer of polymer X?
1,2-dichloroethene
(b)
Putting X in incinerator will cause serious pollution problem. Why?
It is because burning of X will form acidic
hydrogen chloride gas.
26.
An experiment is carried out as shown below:
2H+
+
2 e-H2
(a)
Write an ionic half equation for the reaction occurs at electrode X?
(b)
What will be the colour change around electrode Y after carrying out the experiment for a certain period? Why?
The solution will change from colourless to orange. It is because the negatively charged dichromate ion will
migrate to the positive electrode Y. Dichromate ion is orange in colour.
(c)
What is the purpose of this experiment?
27. Soapless detergent can be made by reacting
a wetting agent by decreasing the
Its
hydrocarbon tail
To show the existence of ions.
petroleum ,
surface tension
sulphuric acid
of water. Its
and sodium hydroxide. It can acts as
－
ionic head—SO3
is hydrophilic.
is hydrophobic. So soapless detergent can dissolve in water and oil. During the cleaning
process, oil is changed to __negatively_________charged oil droplets. The oil droplets will not join together again because
and can be washed away easily.
28.
29.
(a)
What is the condition required for the reaction of butane and bromine? In the presence of sunlight.
(b)
What kind of reaction does the reaction in (a) belong to?
(c)
Is it a redox reaction? Why? Yes. It is because the oxidation number of Br changes from 0 to –1.
(d)
State the observable change when they react?
(a)
Explain why metal is a good conductor of heat.
(b)
(c)
Substitution reaction
The mixture will change from brown to colouless.
It is because metals have mobile electrons.
Explain why sulphur is classified as non-metal? It is because it cannot conduct electricity in solid and liquid state.
The tap water in HK will form scum with soap solution. Is it correct? Explain your answer.
No. It is because the tap water in HK is soft water.