a) Fractional distillation
b) Sublimation
c) Solvent extraction
Kavungya answered the question on March 28, 2019 at 12:12
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After sometimes, the cotton wools X, Y and Z changed color in turn.
(a) What were the...(Solved)
Study the set-up below and answer the questions that follow.
After sometimes, the cotton wools X, Y and Z changed color in turn.
(a) What were the colour changes?
(b) Which cotton wool changed colour first?
(c) Explain why the cotton wools did not change colour at the same time.
Date posted: March 28, 2019. Answers (1)
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Date posted: March 28, 2019. Answers (1)
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Describe what is observed at electrode C.
Date posted: March 28, 2019. Answers (1)
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Calculate:
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(b) The relative formula mass of the acid.
Date posted: March 28, 2019. Answers (1)
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Complete the table by indicating the numbers of electrons and neutrons.
Date posted: March 28, 2019. Answers (1)
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A Student in form four placed a thermometer in molten naphthalene at 850C and recorded the temperature and time until the naphthalene solidified. From the values obtained, the figure below was drawn.
(a) What name is given to such a figure?
(b) Which part of the figure represents the change of state of naphthalene?
(c)In terms of kinetic theory. Explain what happens to molecules along AB.
Date posted: March 28, 2019. Answers (1)
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Describe how you will separate...(Solved)
The table below shows information about three solid substances A, B and C. Study it and answer the question that follow.
Describe how you will separate the three solids from a mixture of the three.
Date posted: March 28, 2019. Answers (1)
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(i) Explain why it is necessary to have the flame at M.
(ii) Write down the equation for the reaction inside the apparatus.
Date posted: March 28, 2019. Answers (1)
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Calculate the volume of carbon (IV) oxide that would be produced if 15g of calcium carbonate reacted with 100cm³ of 2.0M hydrochloric acid (C = 12.0, O = 16.0, Ca = 40.0) molar gas volume = 24000cm³
Date posted: March 28, 2019. Answers (1)
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Date posted: March 28, 2019. Answers (1)
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(a) Graphite
(b) Magnesium Sulphate solution(Solved)
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(a) Graphite
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Date posted: March 28, 2019. Answers (1)
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The diagram below illustrates how lithium would react with steam. Study it then answer the questions that follow.
(a) Write the equation for the reaction that takes place.
(b) Explain why this experiment cannot be carried out with potassium in the same way as shown.
Date posted: March 28, 2019. Answers (1)
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Date posted: March 28, 2019. Answers (1)
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(a) Write the electron arrangements of their ions, N3-, O2- and Na+....(Solved)
The atomic numbers of nitrogen, oxygen and sodium are 7, 8 and 11 respectively.
(a) Write the electron arrangements of their ions, N3-, O2- and Na+.
(b) Arrange the 3 ions in increasing order of size. Give a reason for your answer.
Date posted: March 28, 2019. Answers (1)
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The grid below is part of the periodic table. Study it and answer the questions that follow. The letters are not actual symbols of elements.
(a) What is the name given to the chemical family of element C?
(b) Would element B react with J? Explain.
(c) Compare the melting points of B and M.
Date posted: March 28, 2019. Answers (1)
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Date posted: March 28, 2019. Answers (1)
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Two wooden splints were placed across regions X and Y respectively. Draw labelled diagrams to show the effects observed on the wooden splint placed across each region.
(i) Region X.
(ii) Region Y.
Date posted: March 28, 2019. Answers (1)
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(a) Identify a solution which is
(i) Strongly acidic. _________________________________________
(ii) Strongly basic _________________________________________
(b) Which to solutions would react with lead (II) oxide? Explain.
Date posted: March 28, 2019. Answers (1)
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(a) Sodium nitrate.
(b) Copper (II) nitrate.(Solved)
Write the equation for decomposition of:
(a) Sodium nitrate.
(b) Copper (II) nitrate.
Date posted: March 28, 2019. Answers (1)
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An iron spoon was to be electroplated with silver. Sketch the set-up that could be used.
Date posted: March 28, 2019. Answers (1)