- Thermosoftening plastics are those that can be remelted when heated without losing their properties.
- Thermosetting cannot be remelted once formed.
sharon kalunda answered the question on May 21, 2019 at 12:09
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Draw a dot (.) and cross (x) diagram to show bonding in:-
(i) Ammonium ion (NH4)
(ii) Silane (SiH4)
(N=14...
(Solved)
Draw a dot (.) and cross (x) diagram to show bonding in:-
(i) Ammonium ion (NH4)
(ii) Silane (SiH4)
(N=14 H=1 Si=14)
Date posted:
May 21, 2019
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Answers (1)
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A volume of nitrogen gas diffuses through a porous pot in 70 seconds. How long would it take
400cm3 of carbon (iv) oxide to diffuse through...
(Solved)
A volume of nitrogen gas diffuses through a porous pot in 70 seconds. How long would it take
400cm3 of carbon (iv) oxide to diffuse through the same porous pot? (C=12 O=16 N=14)
Date posted:
May 21, 2019
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Answers (1)
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When a few drops of aqueous ammonia were added to copper (ii) chloride solution, a light blue
precipitate was formed. On addition of excess ammonia solution,...
(Solved)
When a few drops of aqueous ammonia were added to copper (ii) chloride solution, a light blue
precipitate was formed. On addition of excess ammonia solution, a deep blue solution was formed.
(a) Identify the substance responsible for the:-
(i) light blue precipitate.
(ii) deep blue solution.
(b) Write an equation for the reaction leading to observation in (a) (ii) above.
Date posted:
May 21, 2019
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Answers (1)
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Pieces of blue and red litmus papers were placed into a beaker containing water into which
Aluminium Chloride had been dissolved.State the observations made on the...
(Solved)
Pieces of blue and red litmus papers were placed into a beaker containing water into which
Aluminium Chloride had been dissolved.State the observations made on the papers. Explain your answer.
Date posted:
May 21, 2019
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Answers (1)
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Is dissolving of aluminium chloride in water a physical or chemical process? Explain
(Solved)
Is dissolving of aluminium chloride in water a physical or chemical process? Explain
Date posted:
May 21, 2019
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Answers (1)
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Explain why graphite conducts electricity while diamond does not.
(Solved)
Explain why graphite conducts electricity while diamond does not.
Date posted:
May 21, 2019
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Answers (1)
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Name the solution and the catalyst used in preparation of oxygen in the laboratory.
(Solved)
Name the solution and the catalyst used in preparation of oxygen in the laboratory.
Date posted:
May 21, 2019
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Answers (1)
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When 31.2g of hydrated. Aluminium oxide ( Al2O3XH2O) was heated to a constant mass of 20.6g of Aluminium oxide ( Al2O3) was obtained. Determine the value...
(Solved)
When 31.2g of hydrated. Aluminium oxide ( Al2O3XH2O) was heated to a constant
mass of 20.6g of Aluminium oxide ( Al2O3) was obtained. Determine the value of x in
hydrated oxide.(Al= 27.0, O=16.0, H=1.0)
Date posted:
May 21, 2019
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Answers (1)
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Aluminium is not used for marine purpose.Give a reason.
(Solved)
Aluminium is not used for marine purpose.Give a reason.
Date posted:
May 21, 2019
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Answers (1)
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Carbon is not used for the reduction of Aluminium oxides.Give a reason
(Solved)
Carbon is not used for the reduction of Aluminium oxides.Give a reason
Date posted:
May 21, 2019
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Answers (1)
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The flow chart below shows industrial extraction Aluminium metal. Study it and answer the questions that follow.
(i) Explain how process T is carried out.
(ii)...
(Solved)
The flow chart below shows industrial extraction Aluminium metal. Study it and answer the questions that follow.
(i) Explain how process T is carried out.
(ii) Name residue P, give a reason.
(iii) Explain why it is necessary to heat Aluminium oxide in presence of cryolite before
electrolysis is carried out.
Date posted:
May 21, 2019
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Answers (1)
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Describe how sulphuric acid is manufactured from sulphur (VI) oxide.
(Solved)
Describe how sulphuric acid is manufactured from sulphur (VI) oxide.
Date posted:
May 21, 2019
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Answers (1)
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By using a chemical test, how can you distinguish H2S(g) and SO2(g).
(Solved)
By using a chemical test, how can you distinguish H2S(g) and SO2(g).
Date posted:
May 21, 2019
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Answers (1)
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The diagram below shows the preparation of nitric acid.
a) Name solid A.
b) Under what conditions does sulphuric acid react with solid A.
c) What is the...
(Solved)
The diagram below shows the preparation of nitric acid.
a) Name solid A.
b) Under what conditions does sulphuric acid react with solid A.
c) What is the colour of liquid B
d) What is the purpose of cold water
e) 1 cm3 of liquid B was diluted with distilled water and a few drops of copper turnings dropped into it A colourless gas and later brown gas were produced.
(i) Name the colourless gas
(ii) Name the brown gas formed?
(iii) Give an equation for the formation of the brown gas
Date posted:
May 21, 2019
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Answers (1)
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Elements V,W and X have atomic number 17,19 and 20 respectively.
(a) What is the valencies of V and W respectively.
(b) To which groups of the...
(Solved)
Elements V,W and X have atomic number 17,19 and 20 respectively.
(a) What is the valencies of V and W respectively.
(b) To which groups of the periodic table do V, and X belong.
(c) In which periods do elements V and W lie.?
(d) Which of the three elements is a non-metal?
(e) Write down the formula of the compounds formed when:
(i) V reacts with W
(ii) X reacts with Oxygen
f) How many
(i) Neutrons does V have? if its mass number is 35
(ii) Protons does W have ?
Date posted:
May 21, 2019
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Answers (1)
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In the preparation of magnesium carbonate magnesium was burnt in air and the product collected.Dilute sulphuric acid was added and the mixture filtered and cooled....
(Solved)
In the preparation of magnesium carbonate magnesium was burnt in air and the product collected.Dilute sulphuric acid was added and the mixture filtered and cooled. Sodium carbonate was added to the filtrate and the content filtered. The residue was washed and dried to give a white powder.
a) Give the chemical name of the product formed when magnesium burns in air
b) Write a chemical equation for the formation of product.
c) (i) Name filtrate collected after sodium carbonate was added
(ii) Name the white powder.
d) Write chemical equation for the reaction between product in (a) and acid.
e) Name the ions present in the filtrate after addition of sodium carbonate.
f) Write an ionic equation to show the formation of the white powder
g) Write an equation to show what happened when white powder is strongly heated.
Date posted:
May 21, 2019
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Answers (1)
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The scheme below shows some products that can be obtained starting from ethene.
(i) Name the compounds
(ii) Name the process
(iii) State one condition necessary...
(Solved)
The scheme below shows some products that can be obtained starting from ethene.
(i) Name the compounds M,N,T,X,Y and Z
(ii) Name the process B,C and D
(iii) State one condition necessary for the processes in (ii) above to take place.
Date posted:
May 21, 2019
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Answers (1)
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Filter paper dipped in acidified Potassium Manganate (VII) were placed in two
separate gas jars A and B containing pentane and Pent-l-ene respectively. Explain
what was observed...
(Solved)
Filter paper dipped in acidified Potassium Manganate (VII) were placed in two
separate gas jars A and B containing pentane and Pent-l-ene respectively. Explain
what was observed in each case.
Date posted:
May 21, 2019
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Answers (1)
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Draw one of the positional isomer of Butene.
(Solved)
Draw one of the positional isomer of Butene.
Date posted:
May 21, 2019
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Answers (1)
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An aqueous solution of Copper (II) Sulphate was electrolysed using platinum electrodes. When a current was passed a gas that relights a glowing splint was...
(Solved)
An aqueous solution of Copper (II) Sulphate was electrolysed using platinum electrodes. When a current was passed a gas that relights a glowing splint was produced.
(i) Name the electrode which acts as cathode. Give a reason.
(ii) Write an equation for the reaction at the anode.
d) 0.11g of metal R deposited by electrolysis when a current of 0.03 amperes flow for
99 minutes. ( R =92.) ,(1 Faraday = 96500 C)
(i) Find the number of moles of metal deposited.
(ii) Find the number of moles of electrons passed.
(iii) Determine the value of n in the metallic ion Rn+.
Date posted:
May 21, 2019
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Answers (1)