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- Sodium octadecanoate has a chemical formula CH3(CH2)6 COO-Na+, which is used as soap.
Explain why a lot of soap is needed when washing with hard water(Solved)
Sodium octadecanoate has a chemical formula CH3(CH2)6 COO-Na+, which is used as soap.
Explain why a lot of soap is needed when washing with hard water
Date posted: November 1, 2019. Answers (1)
- Write chemical equation to represent the effect of heat on ammonium carbonate(Solved)
Write chemical equation to represent the effect of heat on ammonium carbonate
Date posted: November 1, 2019. Answers (1)
- Explain the environmental effects of burning plastics in air as a disposal method(Solved)
Explain the environmental effects of burning plastics in air as a disposal method
Date posted: November 1, 2019. Answers (1)
- The structure of the monomer phenyl ethene is given below:-(Solved)
The structure of the monomer phenyl ethene is given below:-
a) Give the structure of the polymer formed when four of the monomers are added together
b) Give the name of the polymer formed in (a) above
Date posted: November 1, 2019. Answers (1)
- In the extraction of aluminium form its ore by the use of electrolysis, explain the following observations:-
(i) the graphite anode is replaced from time to...(Solved)
In the extraction of aluminium form its ore by the use of electrolysis, explain the following observations:-
(i) the graphite anode is replaced from time to time
(ii) the steel tank which can also serve as an electrode is also lined with graphite cathode
Date posted: November 1, 2019. Answers (1)
- Aluminum metal is mainly extruded from molten Bauxite by electrolysis.
a) Name the main impurity in this ore.
b) Briefly describe how the impurity is removed from...(Solved)
Aluminum metal is mainly extruded from molten Bauxite by electrolysis.
a) Name the main impurity in this ore.
b) Briefly describe how the impurity is removed from the ore before electrolysis process.
Date posted: November 1, 2019. Answers (1)
- Name the following compounds.(Solved)
Name the following compounds.
Date posted: November 1, 2019. Answers (1)
- One of the steps in the extraction of Zinc metal from its ore is roasting of the ore in excess
oxygen. Write equations for the reactions...(Solved)
One of the steps in the extraction of Zinc metal from its ore is roasting of the ore in excess
oxygen. Write equations for the reactions that take place when the ore in (a) above is roasted
Date posted: November 1, 2019. Answers (1)
- The following table shows some properties of period three elements and their chlorides. Study it and answer the questions that follow.
a)Complete the table by filling...(Solved)
The following table shows some properties of period three elements and their chlorides. Study it and answer the questions that follow.
a)Complete the table by filling in the formula of the missing chlorides.
b)In terms of structure and bonding, explain the following observations:
i)The melting point of aluminium is higher than that of sodium.
ii)The melting point of chlorine is lower than that of sulphur.
iii)The melting point of aluminium chloride is lower than that of magnesium chloride.
c)Sodium chloride dissolves in water to form a neutral solution but aluminium chloride dissolves
to form an acidic solution. Explain this observation.
d)Generally, the first ionization energy increases across the period. Explain
e)Iron (III) oxide was found to be contaminated with magnesium chloride. Describe how a pure dry sample of iron (III) oxide can be obtained.
Date posted: November 1, 2019. Answers (1)
- The diagram below is a simplified apparatus for extraction of sodium. Study it and answer the
equations that follow:-(Solved)
The diagram below is a simplified apparatus for extraction of sodium. Study it and answer the
equations that follow:-
(a) Which substances come out at:- P & Q
(b) What is the role of the diaphragm
(c) Write the equation of the reaction forming sodium
Date posted: November 1, 2019. Answers (1)
- Heated iron forms iron (III) chloride when reacted with chlorine and iron (II) chloride when reacted with hydrogen chloride gas. Explain this difference.
(Solved)
Heated iron forms iron (III) chloride when reacted with chlorine and iron (II) chloride when reacted with hydrogen chloride gas. Explain this difference.
Date posted: November 1, 2019. Answers (1)
- The table below shows some properties of substances I, J, K and L.
Identify the substances with:
a)A metallic bond
b)A covalent bond
c)An ionic bond (Solved)
The table below shows some properties of substances I, J, K and L.
Identify the substances with:
a)A metallic bond
b)A covalent bond
c)An ionic bond
Date posted: November 1, 2019. Answers (1)
- Nitrogen and oxygen gases react according to the equation given below;
a)Explain the effect of increasing temperature on the yield of nitrogen (II) oxide.
b)If 200cm3...(Solved)
Nitrogen and oxygen gases react according to the equation given below;
a)Explain the effect of increasing temperature on the yield of nitrogen (II) oxide.
b)If 200cm3 of nitrogen were used, determine the volume of nitrogen (II) oxide gas produced.
Date posted: November 1, 2019. Answers (1)
- A current of 3A was passed through fused aluminium oxide for 10minutes. Calculate the mass of Aluminium obtained at one electrode (Al = 27.0, IF...(Solved)
A current of 3A was passed through fused aluminium oxide for 10minutes. Calculate the mass of Aluminium obtained at one electrode (Al = 27.0, IF = 96500C)
Date posted: November 1, 2019. Answers (1)
- When air is bubbled through pure water of pH 7.0, the pH drops to 6.0. Explain. (Solved)
When air is bubbled through pure water of pH 7.0, the pH drops to 6.0. Explain.
Date posted: November 1, 2019. Answers (1)
- The table below shows condensed structural formulae of some organic compounds. Use it to answer the questions that follow.
a)State and explain the difference in the...(Solved)
The table below shows condensed structural formulae of some organic compounds. Use it to answer the questions that follow.
a)State and explain the difference in the boiling points of compounds A and E.
b)Write an equation to show the reaction between compounds B and E and give the name of the
product formed.
Equation.
Name of product:
c)Give one chemical test that can be used to identify compound C.
Date posted: November 1, 2019. Answers (1)
- A series of experiments were done using 0.1g pieces of magnesium and dilute hydrochloric acid.
The following results were obtained.
a)Sketch the curve obtained when the...(Solved)
A series of experiments were done using 0.1g pieces of magnesium and dilute hydrochloric acid.
The following results were obtained.
a)Sketch the curve obtained when the volume of gas produced was plotted
against time for each of the experiments and label each as 1, 2 or 3.
b)Write an equation for the reaction that took place
Date posted: November 1, 2019. Answers (1)
- The sketch below shows a graph of temperature against time obtained when a gaseous substance was cooled.
Explain what happens to the gaseous substance between:
a)T and...(Solved)
The sketch below shows a graph of temperature against time obtained when a gaseous substance was cooled.
Explain what happens to the gaseous substance between:
a)T and U
b)U and V
c)V and W
Date posted: November 1, 2019. Answers (1)
- The flow chart below illustrates the extraction of Zinc. Study it and answer the questions that follow:(Solved)
The flow chart below illustrates the extraction of Zinc. Study it and answer the questions that follow:
a) Name:-
i) Gas Q
ii) Liquid R
(iii) Residues S
b) Name the sulphide ore used
c) Before the ore is roasted, it is first concentrated;
(i) Explain why it is necessary to concentrate the ore
(ii) Explain briefly the process of concentrating the ore
d) Write an equation for the reaction that takes place in the:-
(i) Roaster
(ii) Reaction chamber
(e) (i) Name one major impurity present in the sulphide ore used
(ii) Write an equation to show how the impurity in (e)(i) above is removed
f) Given that the sulphide ore contains only 45% Zinc sulphide by mass, calculate :
(i) The mass in grams of Zinc sulphide that would be obtained from 250kg of the ore.
(ii) The volume of Sulphur (IV) oxide that would be obtained from the mass of sulphide
ore at room temperature and pressure
(Zn = 65.4, S = 32.0, O= 16.0, I mole of gas occupies 24.0 liters at r.t.p)
Date posted: November 1, 2019. Answers (1)
- 100cm3 of propane diffuses through a porous plug in 20 seconds. How long would it take 80cm3
of methane gas to diffuse through the same...(Solved)
100cm3 of propane diffuses through a porous plug in 20 seconds. How long would it take 80cm3
of methane gas to diffuse through the same plug? (C = 12.0, H = 1.0)
Date posted: November 1, 2019. Answers (1)