1. Carbon
2. Hydrogen
johnmulu answered the question on February 2, 2017 at 07:05
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In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4 g of the clean magnesium ribbon was placed in a crucible and completely burnt in oxygen. After cooling, the product weighed 4.0 g
a) Explain why it was necessary to clean the magnesium ribbon
b) What observation was made in the magnesium ribbon
c) Why was there an increase in mass
Date posted: February 2, 2017. Answers (1)
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b) Explain your answer in (a) above
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Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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i) a solution containing the red pigment may be prepared
ii) The solution can be shown to be an indicator
Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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10g of sodium hydrogen carbonate were dissolved in 20 cm3 of water in a boiling tube. Lemon juice was then added dropwise with shaking unit there was no further observable change
a) Explain the observation which was made in boiling tube when the reaction was in progress
b) What observation would have been made if the lemon juice had been added to copper turning in a boiling tube? Give a reason
Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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Iron (III) oxide was found to be contaminated with copper (II) sulphate. Describe how a pure sample of iron (III) oxide can be obtained.
Date posted: February 2, 2017. Answers (1)
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Date posted: February 2, 2017. Answers (1)
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When solid A was heated strongly, it gave off water residue. When water was added to the solid residue, the original solid A, was formed
a) What name is given to the process described
b) Give one example of solid A
Date posted: February 2, 2017. Answers (1)
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Date posted: February 1, 2017. Answers (1)
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A sample of water in a beaker was found to boil at 101o C at 1 atmospheric pressure. Assuming that the thermometer was not faulty, explain this observation.
Date posted: February 1, 2017. Answers (1)
- A mixture contains ammonium chloride, copper (II) oxide and sodium chloride. Describe how each of the substances can be obtained from the mixture.(Solved)
A mixture contains ammonium chloride, copper (II) oxide and sodium chloride. Describe how each of the substances can be obtained from the mixture.
Date posted: January 31, 2017. Answers (1)
- Describe a laboratory experiment that can be used to show that the action of heat on hydrated cobalt (II) chloride is a reversible action.(Solved)
Hydrated cobalt (II) chloride exists as pink crystals and anhydrous cobalt (II) chloride is a blue powder. Describe a laboratory experiment that can be used to show that the action of heat on hydrated cobalt (II) chloride is a reversible action.
Date posted: January 31, 2017. Answers (1)
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State and explain the change in mass that occurs when the following substances are separately heated in open crucibles.
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Date posted: January 31, 2017. Answers (1)