Chemistry · Paper 2 · 2021
42 questions 🏝 ZEC ✓ Official ZEC answersChemistry · Paper 2 · 2021
42 questions
3-hour timed simulation · auto-graded · counts toward ranking
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The formula for calculating maximum number of electrons held within energy level is given by 2n^2. The electrons in the second energy level is
The process of coating iron or steel with zinc, a metal that does not rust is
Element X has atomic number 11 and mass number 23. From the given information writes i. Electronic configuration of element X ii. Number of periods of element X in the periodic table iii. State whether the element X, is metal or non-metal
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Section B
Why treated water is the best for use in the laboratory and medical facilities?
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List two (2) chemical properties of water.
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c. Complete the table below, the first one is given as an example. Number Common name Chemical name Formula i. Soda ash Sodium Carbonate Na CO 2 3 ii. Common salt iii. Marble
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Draw and label parts of non-luminous flame
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i. Define water cycle. ii. Water has high surface tension. What does this mean? iii. Why treated water is the best for use in the laboratory and medical facilities? iv. List two (2) chemical properties of water. b. Explain briefly the following terms as they are used in water cycle. i. Condensation ii. Precipitation iii. Collection
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Air is the mixture of different gases. Below are materials that are used to test different gases in air. * Anhydrous copper (II) sulphate * Lime water * Copper turnings From the above information answer the following questions:
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c. Give a brief explanation on the electron arrangement according to Neils Bohr.
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b. Water is neither acidic nor basic, it is neutral. What does this mean?
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Section C
Why fossil fuels are not preferred to be used as a source of fuel?
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