This is an experiment to test for reducing property of copper and oxidative property of nitrogen (iv) oxide
-Air inside combustion tube has oxygen which will otherwise combine with hot copper. So it is essential to pass Nitrogen(iv)oxide before heating to drive air out.
- Cold copper does not combine with oxygen since it has not reach activation energy to combine
Kipssben answered the question on August 20, 2018 at 18:27
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Name the products formed when ammonia (I) Is burnt in air with excess oxygen...
(Solved)
Name the products formed when ammonia:
(I) Is burnt in air with excess oxygen
(II) Oxidized in presence of platinum catalyst
(III) Decompose when heated
Date posted:
August 17, 2018
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Answers (1)
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State two distinctive features of dynamic equilibrium
(Solved)
State two distinctive features of dynamic equilibrium
Date posted:
August 17, 2018
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Answers (1)
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Give three factors that accelerate rusting
(Solved)
Give three factors that accelerate rusting
Date posted:
August 16, 2018
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Answers (1)
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10.26 g of aluminium sulphate were dissolved in 200cm3 water. Calculate the molar concentration of the sulphate ions in the solution
(Solved)
10.26 g of aluminium sulphate were dissolved in 200cm3 water. Calculate the molar concentration of the sulphate ions in the solution (Relative formula mass of aluminium sulphate = 342).
Date posted:
August 15, 2018
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Answers (1)
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An oxide of silicon was found to contain 47% by mass silicon. What is the empirical formula of the oxide? (Si=28,O=16)
(Solved)
An oxide of silicon was found to contain 47% by mass silicon. What is the empirical formula of the oxide? (Si=28,O=16)
Date posted:
August 13, 2018
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Answers (1)
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Determine the number of moles in 13.5 g of aluminium (Al =27)
(Solved)
Determine the number of moles in 13.5 g of aluminium (Al =27)
Date posted:
August 13, 2018
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Answers (1)
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Calculate the mass of 0.4 moles of calcium (Ca=40)
(Solved)
Calculate the mass of 0.4 moles of calcium (Ca =40)
Date posted:
August 13, 2018
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Answers (1)
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What is the temperature on the Kelvin scale of each of the following? (a) 100°C (b) 22°C
(Solved)
What is the temperature on the Kelvin scale of each of the following? (a) 100°C (b) 22°C
Date posted:
August 13, 2018
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Answers (1)
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Why is the boiling point of propanol higher than that of pentane?
(Solved)
Why is the boiling point of propanol higher than that of pentane?
Date posted:
August 13, 2018
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Answers (1)
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A form 4 student carried out an experiment with 40 cubic centimeters of 1.0M hydrochloric acid and Marble...
(Solved)
Rates and reactions:
A form 4 student carried out an experiment with 40 cubic centimeters of 1.0M hydrochloric acid and Marble chips in order to determine rates of reaction using the following steps.
??HCL was poured to a conical flask
??Conical flask was then placed on a weighing balance
??20 grams of marble chips was then added to acid and left for reaction to proceed
??With time, Changes in mass of flask with contents was recorded
(a) State other way in which one can measure rate of reacion(1mk)
(b)(i) Sketch curve that will be obtain if mass of contents in flask is plotted against time label it as (k) (2mks)
(ii) Using the same axes sketch curve that will be obtain if powdered marble had been used(1mk)
(c) Write a chemical equation to show how reaction proceed (1mk)
Date posted:
August 13, 2018
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Answers (1)
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Explain how a mixture of sulphur and sodium chloride can be separated into solid sulphur and sodium chloride
(Solved)
Explain how a mixture of sulphur and sodium chloride can be separated into solid sulphur and sodium chloride
Date posted:
August 2, 2018
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Answers (1)
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Solution of hydrogen chloride gas in water produces hydrogen gas with zinc granules, but solution of hydrogen chloride in toluene doesn't. Explain.
(Solved)
Solution of hydrogen chloride gas in water produces hydrogen gas with zinc granules, but solution of hydrogen chloride in toluene doesn't. Explain. (2 marks)
Date posted:
July 25, 2018
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Answers (1)
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Give one chemical test to distinguish between ethane and ethene
(Solved)
Give one chemical test to distinguish between ethane and ethene.
Date posted:
July 7, 2018
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Answers (1)
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Why do cars in Mombasa rust faster than those in Kisumu?
(Solved)
Why do cars in Mombasa rust faster than those in Kisumu?
Date posted:
July 7, 2018
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Answers (1)
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The density of brass is 8.3g/cm3 and that of tin is 7.3g/cm3. What volume of tin would have the same mass as 73g of brass?
(Solved)
The density of brass is 8.3g/cm3 and that of tin is 7.3g/cm3. What volume of tin would have the same mass as 73g of brass?
Date posted:
July 5, 2018
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Answers (1)
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A student was stung by a bee and sodium hydrogen carbonate was applied to relieve the pain. Explain.
(Solved)
A student was stung by a bee and sodium hydrogen carbonate was applied to relieve the pain. Explain.
Date posted:
July 4, 2018
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Answers (1)
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100g of a radio active substance was reduced to 12.5 g in 15.6 years. Calculate the half-life of the substance
(Solved)
100g of a radio active substance was reduced to 12.5 g in 15.6 years. Calculate the half-life of the substance.
Date posted:
July 4, 2018
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Answers (1)
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Copper (II) oxide and charcoal are both black solids. Describe how you can distinguish them.
(Solved)
Copper (II) oxide and charcoal are both black solids. Describe how you can distinguish them.
Date posted:
July 1, 2018
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Answers (1)
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Explain the following observations. When burning magnesium is lowered into a gas jar of carbon(4) oxide it continues burning, but when burning zinc is lowered into...
(Solved)
Explain the following observations when burning magnesium is lowered into a gas jar of carbon(4) oxide it continues burning,but when burning zinc is lowered into a gas jar of carbon (4) oxide it does not burn.
Date posted:
June 24, 2018
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Answers (1)
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Which alkanol is mixed with a cleansing agent during its preparation?
(Solved)
Which alkanol is mixed with a cleansing agent during its preparation?
Date posted:
June 24, 2018
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Answers (1)