- In fire extinguishers
- In aerated drinks
- Making artificial rain
sharon kalunda answered the question on May 17, 2019 at 10:19
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A piece of marble chip ( calcium carbonate) is put in a beaker containing excess of dilute hydrochloric
acid which is placed on a reading balance....
(Solved)
A piece of marble chip ( calcium carbonate) is put in a beaker containing excess of dilute hydrochloric
acid which is placed on a reading balance. The mass of the beaker and its contents is recorded every
two minutes, as shown in the table.
(a) Why is there a continuous loss of mass of the reaction mixture.
(b) Write an equation for the reaction taking place.
(c ) State two different ways by which the reaction could have been made more rapid.
(d) Why does the mass remain constant after 8 minutes.
(e) State the observations that would be made if a few drops of silver nitrate solution
Was added to 1cm3 of the resulting solution followed by ammonia solution.
Date posted:
May 17, 2019
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Answers (1)
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The set-up below represents electrolysis of dilute sulphuric (VI) acid.
(Solved)
The set-up below represents electrolysis of dilute sulphuric (VI) acid.
(a) Identify gases M and N
(b) Write an ionic equation for the production of gas M.
(c ) At what electrode does reduction take place. Explain your answer.
(d) State the most suitable electrodes that can be used in this experiment.
Explain your answer.
Date posted:
May 17, 2019
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Answers (1)
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The scheme below shows various reactions starting with ammonia. Study it and
answer the questions that follow.
(Solved)
The scheme below shows various reactions starting with ammonia. Study it and
answer the questions that follow.
(i) List the raw materials used in the manufacture of ammonia.
(ii) What catalyst is used in step I ?
(iii) Write an equation for the reaction that occurs between ammonia and oxygen in
presence of the catalyst.
(iv) Identify the process in step II
(v) Using an appropriate equation, explain how the reaction in step III occurs ?
(vi) What should be added to solution K to form solid L ?
(vii) (a) (i) Write the formula of compound J.
(ii) Calculate the mass of compound J that would contain 14g of nitrogen
( H = 1, N = 14, O = 16 )
(b) State two advantages of ammonium phosphate over ammonium nitrate.
Date posted:
May 17, 2019
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Answers (1)
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The diagram below outlines industrial preparation of bleaching powder.
(Solved)
The diagram below outlines industrial preparation of bleaching powder.
(i) Give the chemical name of bleaching powder
(ii) Identify substance R
(iii) Explain why water in which bleaching powder has been added needs a lot of soap
during washing.
Date posted:
May 17, 2019
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Answers (1)
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The reaction of water and calcium gave gas Q collected as in the diagram below
(Solved)
The reaction of water and calcium gave gas Q collected as in the diagram below
(i) Identify gas Q
(ii) Explain why the solution left after the reaction is a weak base.
Date posted:
May 17, 2019
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Answers (1)
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Dry hydrogen chloride gas was passed through heated iron wire as shown in the diagram
below
(Solved)
Dry hydrogen chloride gas was passed through heated iron wire as shown in the diagram
below
a) (i) How can the identity of the substance burning with flame Z be confirmed.
(ii) What is observed in combustion tube during the experiment?
(iii) Write the equation for the reaction taking place in the combustion tube.
(iv) Chlorine gas was passed over the product obtained in the combustion tube to give
another product Q
a) State one precaution that should be taken. Explain
b) Identify product Q
c) The total mass of product Q formed was found to be 5.3g. Calculate the volume of
chlorine gas used.
(Cl = 35.5, Fe= 56, Molar gas volume at room temperature = 2400cm3)
Date posted:
May 17, 2019
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Answers (1)
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The flow chart below outlines some of the process involved during extraction of copper.
(Solved)
The flow chart below outlines some of the process involved during extraction of copper.
(i) Write the formula of copper pyrite.
(ii) Name liquid T
(iii) Write equations for the reactions taking place in the 2nd roasting furnace.
(iv) Identify substance B and write equation for the reaction that take place in the smelting furnace.
(v) State the purpose of substance F.
Date posted:
May 17, 2019
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Answers (1)
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Study the scheme below and answer the questions that follow.
(Solved)
Study the scheme below and answer the questions that follow.
(i) Identify the product B.
(ii) Name the compounds C and E.
(iii) State the conditions for step 1
(iv) Write the equation for the reaction leading tot the formation of methane.
(v) State two industrial uses of methane.
(vi) Identify the reagent D
Date posted:
May 17, 2019
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Answers (1)
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The graph below was obtained from an experiment used to investigate the reaction
between Zinc granules and 2M hydrochloric acid.
(Solved)
The graph below was obtained from an experiment used to investigate the reaction
between Zinc granules and 2M hydrochloric acid.
a) Calculate the rate of reaction when t = 60seconds.
b) Suggest how the rate of the above reaction can be reduced so that it can be studied more closely at the same temperature.
Date posted:
May 17, 2019
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Answers (1)
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Describe two observable characteristics of a luminous flame
(Solved)
Describe two observable characteristics of a luminous flame.
Date posted:
May 17, 2019
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Answers (1)
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Write a chemical equation for the combustion of laboratory gas , when the
Bunsen burner produces a non-luminous flame.
(Solved)
Write a chemical equation for the combustion of laboratory gas , when the
Bunsen burner produces a non-luminous flame.
Date posted:
May 17, 2019
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Answers (1)
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State the main differences between alkanes and alkenes in terms of the following;
(Solved)
State the main differences between alkanes and alkenes in terms of the following;
i) Structure and bonding
ii) Reaction with chlorine gas.
Date posted:
May 17, 2019
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Answers (1)
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Describe how you would obtain pure solid samples of each of the following components of a
solid mixture containing ; Lead (II) chloride, Sodium carbonate and...
(Solved)
Describe how you would obtain pure solid samples of each of the following components of a
solid mixture containing ; Lead (II) chloride, Sodium carbonate and calcium sulphate.
Date posted:
May 17, 2019
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Answers (1)
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In an experiment,1g of calcium carbonate was completely dissolved 100cm3 of 0.25M excess hydrochloric acid.Calculate the molar concentration of the acidic solution formed. (Ca = 40;...
(Solved)
In an experiment,1g of calcium carbonate was completely dissolved 100cm3 of 0.25M excess hydrochloric acid.Calculate the molar concentration of the acidic solution formed. (Ca = 40; C = 12; O =16).
Date posted:
May 17, 2019
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Answers (1)
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Explain the meanings of the following physical properties of laboratory gases.
(Solved)
Explain the meanings of the following physical properties of laboratory gases.
i) A chocking smell.
ii) An irritating smell.
iii) A neutral gas
Date posted:
May 16, 2019
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Answers (1)
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An element X has atomic number 3, relative atomic mass 6.94 and consists of two isotopes
of mass numbers 6 and 7.
(Solved)
An element X has atomic number 3, relative atomic mass 6.94 and consists of two isotopes
of mass numbers 6 and 7.
a) What is the mass number of the more abundant isotope of X?
b) Calculate the relative abundance of each of the isotopes.
Date posted:
May 16, 2019
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Answers (1)
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State two large scale uses of hard water.
(Solved)
State two large scale uses of hard water.
Date posted:
May 16, 2019
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Answers (1)
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Explain how dilute hydrochloric acid can be used to determine the type of hardness in a sample of tap water.
(Solved)
Explain how dilute hydrochloric acid can be used to determine the type of hardness in a sample of tap water.
Date posted:
May 16, 2019
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Answers (1)
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A factory produces 63.6 tonnes of anhydrous Na2CO3 on a certain. Calculate the number of tonnes of sodium chloride used on this particular day. Assume...
(Solved)
A factory produces 63.6 tonnes of anhydrous Na2CO3 on a certain. Calculate the number of tonnes of sodium chloride used on this particular day. Assume the plant is working at 100% efficiency.(C = 12, H = 1, Cl = 35.5, Ca = 40, Na = 23)
Date posted:
May 16, 2019
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Answers (1)
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The flow chart below shows the manufacture of sodium carbonate. Study it carefully and
answer the questions that follow.
(Solved)
The flow chart below shows the manufacture of sodium carbonate. Study it carefully and
answer the questions that follow.
a)
i). What is ammoniacal brine?
ii). Ammoniacal brine reacts with carbon (IV) oxide to form a mixture of two salts
which produce Q. Write an equation to show formation of Q
Name two processes that are used to separate Q into NH4Cl and P
b) Give two uses of sodium carbonate produced in the process.
c)i). Name the substance that reacts with water that comes into the slaker
ii). What happens at the kiln?
d) Write an equation for the reaction that occurs when P is heated to form solid
Na2 CO3
e) Name two substances that are recycled in the process.
Date posted:
May 16, 2019
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Answers (1)