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(a) (i) To remove the large solid particles from water
(ii) Sedimentation
(iii) I. Cause the small suspended particles to settle down.
II. To kill germs/microorganisms/microbes
(b) (i) Permanent
(ii) Addition of Na2CO3 which precipitates
Mg2+ as MgCO3
OR
Use of ion exchange resin which will remove Mg2+ or distillation where MgSO4 is left behind as residue.
(c) (i) Add excess calcium oxide to dilute HCl/HNO3 filter to obtain the filtrate and add aqueous Na2CO3/K2CO3 to the filtrate to precipitate CaCO3; wash the precipitate with distilled water and dry it between filter
papers
(ii) Used as chalk
- Used in the extraction of iron.
sharon kalunda answered the question on March 19, 2019 at 14:02
- a)The set up below was used during electrolysis of aqueous copper (II) sulphate using inert electrodes.(Solved)
a)The set up below was used during electrolysis of aqueous copper (II) sulphate using inert electrodes.
i) Name a suitable pair of electrodes for this experiment.
ii) Identify the ions and cations in the solution.
iii) On the diagram label the cathode.
iv) Write ionic equations for the reactions that took place at the anode
v) Explain the change that occurred to the Copper (II) Sulphate solution during the experiment.
vi) During the electrolysis a current of 2 amperes was passed through the solution for 4 hours. Calculate the volume of the gas produced at the anode. (1 Faraday = 96500 coulombs and volume of gas at room temperature is 24000cm3 )
b) i) Draw a diagram to show how an impure copper lump can be refined through electrolysis.
ii) State one other use of electrolysis other than the one shown in b (ii) above.
Date posted: March 19, 2019. Answers (1)
- The electron arrangement of ions Q2- and R3+ are as 2, 8, 8, and 2,8 respectively.
(a) Write the electron arrangement of the elements Q and...(Solved)
The electron arrangement of ions Q2- and R3+ are as 2, 8, 8, and 2,8 respectively.
(a) Write the electron arrangement of the elements Q and R
(b)Write the formula of the compound that would be formed between Q and R
Date posted: March 19, 2019. Answers (1)
- (a) Below is a paper chromatogram of pure substances W, X and Y(Solved)
(a) Below is a paper chromatogram of pure substances W, X and Y
The mixture K contains substances W and X only. Indicate on the diagram the chromatogram of K.
(b) State one application of chromatography.
Date posted: March 19, 2019. Answers (1)
- The atomic number of an element A is 11 and that of B to 8.(a)Write down a possible formula of compound formed between A and...(Solved)
The atomic number of an element A is 11 and that of B to 8.
(a)Write down a possible formula of compound formed between A and B.
(b)Draw a dot (•) and cross (×) diagram to show bonding in compound farmed.
Date posted: March 19, 2019. Answers (1)
- The table below shows the effect of passing an electric current through substances using unreactive electrodes,and a bulb in the circuit.(Solved)
The table below shows the effect of passing an electric current through substances using unreactive electrodes,and a bulb in the circuit.
a)Identify the experiments in which the bulb did not light.
(b)Explain your answer in (a) above.
Date posted: March 19, 2019. Answers (1)
- Moist hydrogen sulphide gas was passed through a tube containing wet sulphur (IV) oxide gas as shown below.(Solved)
Moist hydrogen sulphide gas was passed through a tube containing wet sulphur (IV) oxide gas as shown below.
(a) State the observation (s) made.
(b) Write an equation for the reaction above.
(c) Giving a reason, which substance undergoes reduction above.
Date posted: March 19, 2019. Answers (1)
- Give two differences between chemical reactions and nuclear reactions.(Solved)
Give two differences between chemical reactions and nuclear reactions.
Date posted: March 19, 2019. Answers (1)
- 0.585g of sodium chloride were dissolved in 50cm³ of de-ionised water. The temperature of the water dropped from 29°C to 17°C. Find the molar heat...(Solved)
0.585g of sodium chloride were dissolved in 50cm³ of de-ionised water. The temperature of the water dropped from 29°C to 17°C. Find the molar heat of solution of sodium chloride. Specific heat capacity of solution 4.2 kJk-2Kg-1, density of solution is 1g/cm³. (Na - 23.0, Cl = 35.5)
Date posted: March 19, 2019. Answers (1)
- Study the chart below and answer the question that follow:(Solved)
Study the chart below and answer the question that follow:
(a) Identify
(i) the metal ions in solution K.
(ii) the white precipitate L.
(b) What property of the white precipitate L is illustrated by steps I and II
Date posted: March 19, 2019. Answers (1)
- Study the set-up below and answer the questions that follow.
(Solved)
Study the set-up below and answer the questions that follow.
(a) Write an equation for the reaction that took place.
(b) What observations is made in the combustion tube.
(c) Name another gas which could be used in place of carbon (II) oxide.
Date posted: March 19, 2019. Answers (1)
- The boiling points of some compounds of hydrogen with some elements in group 4 and 6 of the periodic table are given below.(Solved)
The boiling points of some compounds of hydrogen with some elements in group 4 and 6 of the periodic table are given below.
a) Which of the compounds CH4 and SiH4 has the stronger inter molecular forces?Explain.
(b) Explain why the boiling points of H2O and H2S show different trends from that of CH4 and SiH4.
Date posted: March 19, 2019. Answers (1)
- Sulphur is a component in fuels. Explain the effects of continued use of sulphur containing fuels on the
environment.(Solved)
Sulphur is a component in fuels. Explain the effects of continued use of sulphur containing fuels on the
environment.
Date posted: March 19, 2019. Answers (1)
- The table below shows the number of valence electrons of elements X, Y and Z.(Solved)
The table below shows the number of valence electrons of elements X, Y and Z.
(a) Explain why X and Z would not be expected to form a compound.
(b) Write an equation to show the effect of heat on the carbonate of Z.
(c) Write the formula for the most stable ion of element Y.
Date posted: March 19, 2019. Answers (1)
- a)Study the flow chart below and answer questions that follow.(Solved)
a)Study the flow chart below and answer questions that follow.
Name substances. W,Y
(b) An organic compound K reacted with bromine to produce 2, 3 - dibromobytane .
(i) Name the compound K.
(ii) Draw the structural formular of compound K.
Date posted: March 19, 2019. Answers (1)
- In terms of structure and bonding explain why silicon (IV) oxide is a solid while sulphur (IV) oxide is a gas at room temperature.(Solved)
In terms of structure and bonding explain why silicon (IV) oxide is a solid while sulphur (IV) oxide is a gas at room temperature.
Date posted: March 19, 2019. Answers (1)
- A cell is represented as Zn(S) / Zn2+(aq) // Cu2+(aq) / Cu(S) write down
(i) The oxidation half equation.
(ii) The reduction half equation.
(iii) The...(Solved)
A cell is represented as Zn(S) / Zn2+(aq) // Cu2+(aq) / Cu(S) write down
(i) The oxidation half equation.
(ii) The reduction half equation.
(iii) The overall cell equation.
Date posted: March 19, 2019. Answers (1)
- The data given below was recorded when metal M was completely burnt in air. M is not the actual symbol of the metal. (RAM M...(Solved)
The data given below was recorded when metal M was completely burnt in air. M is not the actual symbol of the metal. (RAM M = 56.0, O=16)
Mass of empty crucible and lid = 5.240g
Mass of crucible, lid and metal m = 5.352g
Mass of crucible, lid, metal oxide = 5.400g
(a) Determine the mass of
(i) Metal m
(ii) Oxygen.
(b) Determine the empirical formula of the meat oxide.
Date posted: March 19, 2019. Answers (1)
- Study the flow chart below and answer the question that follow.(Solved)
Study the flow chart below and answer the question that follow.
(i) Name the following substance
Gas W
Solid Y
ii) Write an equation for the formation of the brown precipitate .
Date posted: March 19, 2019. Answers (1)
- Solutions may be classified as strongly basic, weakly basic neutral weakly acidic, strongly acidic. The
information below gives solution and their pH values. Study it and...(Solved)
Solutions may be classified as strongly basic, weakly basic neutral weakly acidic, strongly acidic. The
information below gives solution and their pH values. Study it and answer the questions that follow.
Classify the solution in the table above using the stated classification B, C & D
Date posted: March 19, 2019. Answers (1)
- A radioactive isotope decays to 50 grammes in 100 days. The half-life of the isotope is 25 days. Calculate the initial mass of the isotope.(Solved)
A radioactive isotope decays to 50 grammes in 100 days. The half-life of the isotope is 25 days. Calculate the initial mass of the isotope.
Date posted: March 19, 2019. Answers (1)