Hydrated cobalt (II) chloride is heated in a boiling tube and the vapour produced condensed in a test-tube. Cobalt (II) chloride turns from pink to blue. When water is added back to anhydrous cobalt (II) chloride it turns back to pink.
raphael answered the question on January 31, 2017 at 12:35
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State and explain the change in mass that occurs when the following substances are separately heated in open crucibles
(Solved)
State and explain the change in mass that occurs when the following substances are separately heated in open crucibles.
(a) Copper metal
(b) Copper (II) nitrate
Date posted:
January 31, 2017
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Answers (1)
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Name the regions labeled C and D in the Bunsen burner below
(Solved)
The diagram below shows a Bunsen burner when in use.
Date posted:
January 28, 2017
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Answers (1)
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What are the differences between luminous and no-luminous flames?
(Solved)
What are the differences between luminous and no-luminous flames?
Date posted:
January 28, 2017
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Answers (1)
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State and explain two reasons why hydrogen is very attractive fuel compared to fossils
(Solved)
Natural gas, coal and oil are known as fossil fuels. They are major sources of energy. Hydrogen gas is also a source of energy. State and explain two reasons why hydrogen is very attractive fuel compared to fossils.
Date posted:
January 16, 2017
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Answers (1)
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What is a fuel?
(Solved)
Define what a fuel is.
Date posted:
January 16, 2017
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Answers (1)
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What is molar heat of vaporization
(Solved)
What is molar heat of vaporization? Explain.
Date posted:
January 16, 2017
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Answers (1)
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Explain why graphite can be used as a lubricant while diamond cannot
(Solved)
Explain why graphite can be used as a lubricant while diamond cannot.
Date posted:
January 16, 2017
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Answers (1)
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State two non crystalline (Amorphous) form of carbon
(Solved)
Diamond and graphite are crystalline forms of cation. State two non crystalline (Amorphous) form of carbon.
Date posted:
January 16, 2017
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Answers (1)
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State two observations made when excess hydrogen suphide gas is bubbled into copper (II) sulphate solution
(Solved)
State observations made when excess hydrogen suphide gas is bubbled into copper (II) sulphate solution.
Date posted:
January 16, 2017
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Answers (1)
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A student attempted to prepare hydrogen sulphide gas and collected the gas over cold water
(Solved)
A student attempted to prepare hydrogen sulphide gas and collected the gas over cold water. The student collected only a few bubbles of gas. Explain.
Date posted:
January 16, 2017
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Answers (1)
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Describe how a pure sample of zinc sulphate can be prepared in the laboratory starting with zinc oxide
(Solved)
Starting with zinc oxide, describe how a pure sample of zinc sulphate can be prepared in the laboratory.
Date posted:
January 16, 2017
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Answers (1)
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A form three student added sodium carbonate solution to a solution of aluminium chloride in water
(Solved)
A form three student added sodium carbonate solution to a solution of aluminium chloride in water. A white precipitate was formed. The precipitate soon dissolved liberation a colourless gas.
i) What is the white precipitate?
ii) Explain why the precipitate dissolves?
Date posted:
January 16, 2017
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Answers (1)
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Magnesium and silicon are both in period III of the periodic table
(Solved)
Magnesium and silicon are both in period III of the periodic table. The atomic radius of the magnesium is found to be higher than silicon. Explain this observation.
Date posted:
January 16, 2017
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Answers (1)
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Nitrogen (II) oxide is produced in the internal combustion engines
(Solved)
Nitrogen (II) oxide is produced in the internal combustion engines. State and explain how it affects the environment.
Date posted:
January 16, 2017
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Answers (1)
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Name a pair of suitable reagents that can be used to prepare nitrogen (II) oxide
(Solved)
Name a pair of suitable reagents that can be used to prepare nitrogen (II) oxide in the laboratory.
Date posted:
January 16, 2017
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Answers (1)
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State Graham's law
(Solved)
State Graham's law.
Date posted:
January 16, 2017
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Answers (1)
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Name the two types of Bunsen burner flame and state the conditions under which each one of them is formed
(Solved)
Name the two flames produced by a Bunsen burner and the conditions under which they are produced.
Date posted:
January 16, 2017
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Answers (1)
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State two factors that should be considered when choosing a fuel for cooking?
(Solved)
What factors should be considered when choosing a fuel for cooking?
Date posted:
January 14, 2017
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Answers (1)