The mass number of a carbon atom that contains six protons, eight neutrons, and six electrons is
A.6
B.14
C.8
D.12
E.20
2.10 alamas
Match the items in LIST A with the responses in LIST B by writing the letter of the correct response beside the item number.
(i)
Its hydroxide is used in soil treatment.
1 alama
(ii)
It is obtained from its ore in the blast furnace.
1 alama
(iii)
It gives a lilac colour when placed in a non-luminous flame.
1 alama
(iv)
It forms an insoluble sulphate.
1 alama
(v)
It is in the same group in the periodic table with nitrogen.
1 alama
(vi)
It reacts with hydrogen to form a compound which is a liquid at room temperature.
1 alama
(vii)
It is used in filament lamps.
1 alama
((viii)
It is the strongest oxidizing agent among the halogens.
1 alama
(ix)
It exists in three main forms.
1 alama
(x)
Its chloride is added to food in order to give taste.
1 alama
Boresha ili kuona majibu ya mfano.
Sehemu B
3.0 alamas
SECTION B (54 marks)
Answer all questions in this section.
(a)
List two methods which are used to prevent rusting of iron.
2 alama
((a)(i)
List two methods which are used to prevent rusting of iron.
0 alama
(b)
State three properties that make aluminium useful in overhead cables.
3 alama
(b)
State three properties that make aluminium useful in overhead cables.
0 alama
Boresha ili kuona majibu ya mfano.
4.0 alamas
The reaction which produces methanol from carbon monoxide and hydrogen is represented by the equation CO(g) + 2H₂(g) ⇌ CH₃OH(g) ΔH = 94kJmol¹.
The reaction is carried out at high pressure to give a good yield of methanol.
(a)
Give three examples in each of the following:
(i) Solid fuel
(ii) Gaseous fuel.
0 alama
(a)
Give three examples in each of the following:
(i) Solid fuel
(ii) Gaseous fuel.
2 alama
(b)
With a reason, state whether a high temperature or low temperature will give a better yield of methanol.
3 alama
((b)(i)
With a reason, state whether a high temperature or low temperature will give a better yield of methanol.
0 alama
Boresha ili kuona majibu ya mfano.
5.0 alamas
Use the knowledge of periodic Table to complete Table 1.
Table 1
S/n
Name of element
Atomic number
Electronic configuration
(i)
Lithium
(ii)
13
(iii)
2.8.7
(a)
State the trend in reactivity of group I elements in the Periodic Table and give reasons for it.
4 alama
((a)(i)
State the trend in reactivity of group I elements in the Periodic Table and give reasons for it.
0 alama
(b)
Use the knowledge of periodic Table to complete Table 1.
5 alama
(b)
Use the knowledge of periodic Table to complete Table 1.
0 alama
Boresha ili kuona majibu ya mfano.
6.6 alamas
Which crop grows best in the:
Suggest one best method for separating each of the following mixtures:
(a)
Use the information in Table 2 to answer the following questions:
(i) Which crop grows best in acidic soil?
(ii) Which crop requires a neutral soil?
(iii) Which crop prefers a slightly alkaline soil?
(iv) State the range of pH values suitable for growing cabbage and cauliflower.
4 alama
((a)(i)
Neutral soil?
1 alama
((b)(i)
Pieces of iron and sand.
1 alama
Boresha ili kuona majibu ya mfano.
7.6 alamas
Briefly explain what will happen when
Give three applications of the process of neutralization in daily life.
((a)(i)
a bottle containing $\text{AgNO}_3$ is left open?
2 alama
(b)
Give three applications of the process of neutralization in daily life.
3 alama
Boresha ili kuona majibu ya mfano.
8.12 alamas
Give the names or formula of the two chemicals that would be used in the laboratory to make each of the following gases. State a simple test that could be used to identify each gas.
Suggest a suitable indicator for the following titrations:
((a)(i)
Carbon dioxide.
2 alama
((b)(i)
Ethanoic acid against potassium hydroxide solution.
1 alama
Boresha ili kuona majibu ya mfano.
9.7 alamas
Compound X contains 24.24% carbon, 4.04% hydrogen and 71.72% chlorine. Given that, the vapour density of X is 49.5.
Calculate the molecular formula of the compound X.
Draw and name the displayed/open structure formula of the possible isomer(s) from the molecular formula determined.
((a)(i)
Name other type(s) of chemical bond formed by fluorine with other elements. Give an example of a compound in which fluorine form this type of bond.
2 alama
((b)(i)
Draw and name the displayed/open structure formula of the possible isomer(s) from the molecular formula determined.
1 alama
Boresha ili kuona majibu ya mfano.
Sehemu C
0.0 alamas
Protons neutrons and electrons particles are located in the atoms; fill in the missing information in Table 4 about these particles.
Table 4
Particles Relative mass Relative charge Location
Proton
Electron 1
1840
Neutron 0 In the nucleus
Table 4
Particles
Relative mass
Relative charge
Location
Proton
Electron
1
1840
Neutron
0
In the nucleus
(i)
Which samples contain hard water?
0 alama
(ii)
Which sample contains temporary hard water? Give a reason.
0 alama
Boresha ili kuona majibu ya mfano.
11.0 alamas
(a)
A steady current of 2A was passed through a solution containing ions of a metal (X$^{2+}$) for nine minutes. The mass of metal X that was liberated were 0.3552 g. Calculate the molar mass of metal X.
0 alama
(i)
Name C$_5$H$_{12}$ according to the IUPAC system.
1 alama
(a)
Calculate the molar mass of metal X.
4 alama
(proto)
Fill in the missing information for Proton.
1 alama
(elect)
Fill in the missing information for Electron.
1 alama
(ii)
Name CH$_3$
|
CH$_3$CH$_2$-C-CH$_2$OH
|
CH$_3$ according to the IUPAC system.
1 alama
(neutr)
Fill in the missing information for Neutron.
1 alama
(iii)
Name CH$_3$
|
CH$_3$-C-CH$_2$OOH
|
CH$_3$ according to the IUPAC system.
1 alama
((b)(i)
Name the following compounds according to the IUPAC system.
CH$_3$
|
CH$_3$ — C — CH$_2$OOH.
|
H
0 alama
Boresha ili kuona majibu ya mfano.
12.0 alamas
Describe the extraction of iron from the haematite ore and write all the chemical equations for the reactions involved in each stage of extraction.
(none)
Describe the extraction of iron from the haematite ore and write all the chemical equations for the reactions involved in each stage of extraction.
8 alama
Boresha ili kuona majibu ya mfano.
13.0 alamas
Addition of inorganic fertilizers in the farm is not as important as addition of organic manure. Discuss the correctness of this statement in four points.
(none)
Discuss the correctness of the statement 'Addition of inorganic fertilizers in the farm is not as important as addition of organic manure' in four points.
4 alama
