SECTION -J(40 Marks)
(Answer all Questions)
Question 1.
A) Answer the questions below, relating your answers only to salts in the following that:
Sodium chloride, anhydrous calcium chloride, copper sulphate -5-water.
i) What name is given to the water in the compound copper sulphate -5-water?
ii) If copper sulphate -5-water is heated, the water is driven off leaving anhydrous copper sulphate.
a) What is the colour of anhydrous copper sulphate?
b) By what means, other than heating, could you dehydrate copper sulphate -5-water and obtain anhydrous copper sulphate?
iii) What is deliquesce?
iv) Which one of the salts in the given list is deliquescent? (5)
B) State what you see when:
i) A piece of moist blue litmus paper is placed in a gas jar of chlorine.
ii) A piece of moist red litmus paper is placed in a gas jar of ammonia.
iii) silver nitrate solution is added to dilute hydrochloric acid.
iv) Zinc oxide is heated.
v) A glowing splint is introduced into a gas jar containing oxygen. (5)
C) Write correctly balanced equation for the following reactions:
i) Molten sodium and chlorine.
ii) nitrogen and oxygen when lightning strikes.
iii) Iron and dilute sulphuric acid.
iv) Decomposition of hypochlorous acid in sunlight.
v) Action of heat on potassium nitrate.
D) A substance X gives a persistent yellow colour in non-luminous flame, The substance reacts neither Dil or conc. Hydrochloric acid. Its solution gives a white precipitate with barium chooride solution, insoluble in hydrochloric acid.
i) What are cation and anion in X?
ii) Give the balanced equation in respect of above reaction.
iii) Give the popular name with formula of a hydrated sample of the salt. (5)
E) The compound Na₂B₄O₇.10H₂O is commonly known as borax. When litmus is added to a solution of borax it turns blue.
i) What can you say about the pH of borax solution ?
ii) Calculate the percentage of boron(B) in borax.
(H=1, B= 11, O= 16, Na= 23. Answer correct to 1 decimal place). (5)
F) i) Sodium hydroxide solution can be used to distinguish between iron(II) sulphate solution and iron (III) sulphate solution because these solutions give different coloured precipitates with sodium hydroxide solution. Give the colour of the precipitate formed with:
a) iron(II) sulphate solution.
b) iron (III) solution.
ii) What will you see when barium chooride solution is added to iron II) sulphate solution?
iii) How will the action of dilute hydrochloric acid on sodium carbonate and sodium sulphite enables you to distinguish these two compounds? (5)
G) Choosing only words from the following list write down the appropriate words to fill in the blanks (i) to (v) below:
anions, anode, cathode, cations, electrode, electrolyte, nickel, voltameter.
To electroplate an article with nickel requires an (i)___ which must be a solution containing (ii)____ions. The article to be plated is placed as (iii)_____of the cell in which the plating is carried out. The (iv)___of the cell is made from pure nickel. The ions which are attracted to the negative electrode and discharged are called (v)______.
H)
SECTION -II(40 Marks)
(Answer any four questions)
Question 2.
a) i) Name the oxide of sulphur which reacts with water to give sulphuric acid.
ii) In the Contact Process, the direct reaction between the oxide of sulphur and water is avoided. In this process, what does the oxide of sulphur react with instead of water and what is the name of the product?
iii) Give the name and formula of the acid salt which can give sodium ions and sulphate ions in solution. (4)
b) i) Name the zinc compound in zinc blende.
ii) Concentrated nitric acid has yellow tinge. This colour is removed by blowing air in it.
iii) Hydrogen is a non-metal, even then it discharge at cathode. (3)
c) Write correctly balanced equations for the reaction of dilute sulphuric acid with each of the following:
i) Copper carbonate.
ii) lead nitrate solution.
iii) zinc hydroxide. (3)
Question 3.
a) The following reactions are carried out:
A: Nitrogen+ metal-->compound X
B: X+ water --> ammonia+ another compound.
C: Ammonia+ metal oxide --> metal + water+ nitrogen.
i) One metal that can be used for reaction A is magnesium.
(1) State the conditions for the reaction.
(2) Write the formula of the compound X formed when nitrogen and magnesium react together.
ii) Write the correctly balanced equation for reaction B where X is the compound formed between nitrogen and magnesium.
iii) What property of ammonia is demonstrated by reaction C ? (4)
b) Industrially, ammonia is obtained by direct combination between nitrogen and hydrogen.
i) Write the correctly balanced equation for the direct combination or nitrogen with hydrogen.
ii) Which of the metals iron, platinum, copper catalyst this direct combination?
iii) Is the formation of ammonia promoted by the use of high pressure or low pressure? (3)
c)i) Is ammonia more dense or less dense than air ?
ii) What property of ammonia is demonstrated by the Fountain Experiment?
iii) Write the correctly balanced equation for the reaction between ammonia and sulphuric acid. (3)
Question 4.
a) i) The compound A has the following percentage composition by mass: carbon 26.7%, oxygen 71.1%, hydrogen 2.2%. determine the empirical formula of A.(work to one decimal place) (H=1, C= 12, O= 16).
ii) If the relative molecular mass of A is 90, what is the molecular formula of A!
iii) The compound A is a weak acid. What is meant by this statement? (6)
b) Ammonia burns in oxygen and the combustion, in the presence of a catalyst, may be represented by:
2NH₃ + 5/2 O₂ ---> 2NO + 3H₂O.
i) What mass of steam is produced when 1.5g of nitrogen monoxide is formed?
ii) What volume of oxygen, at STP is required to form 10 moles of products ?
(H=1, N=14, O=16. 1 mole of a gas occupies 22.4 dm³(22.4 litres) at STP. (4)
Question 5.
a) The table below compares some properties of metals and nonmetals. Write down the missing statements (i) to (iv):
Metal Non metal
i) ___ poor conductor of heat
Not malleable (ii) _____
Form positive ions (iii)_____
iv) ____ for acidic oxides. (4)
b)i) Metals are generally solid at room temperature. Name the metal which is liquid at room temperature (say 25° C).
ii) Which allotrope of the non-metal carbon conducts electricity ? (2)
c)i) How many valence electrons are present in:
A) metals
B) non metals
ii) Name all the particles found in a solution of sodium chloride. (4)
Question 6
a) i) Ethane and chlorine react together to form monochloroethane (ethyl chloride)
A) write down the structural formula of Ethane.
B) what types of reaction has taken place between Ethane and chlorine ?
ii) The type of reaction between ethene and chlorine is different from that between Ethane and chlorine.
A) what is the type of reaction between ethene and chlorine ?
B) What features of the Ethene structure makes such a reaction possible ?
C) name the product of the reaction between Ethene and chlorine. (5)
b) Ethane burns completely in air or oxygen to give carbon dioxide (and water vapour). With a limited supply of air/oxygen carbon monoxide is formed. The same gases are found in automobiles exhaust gases. Both gasrs can be considered as a atmospheric pollutant.
i) write the equation for the complete combustion of ethane.
ii) what dangerous is associated with carbon monoxide ?
iii) what effect is associated with too much carbon dioxide in atmosphere?
iv) burning acetylene(ethyne) in oxygen under appropriate conditions produces a very hot flame. What is his hot flame used for ? (5)
Question 7.
a) solution P as a pH of 13, solution Q has a pH of 6 and solution R has a pH of 2.
i) Which solution will liberate ammonia from ammonium sulphate on heating ?
ii) which solution is strongest acid.
iii) which solution contains salute molecules as well as ions ? (3)
b) i) Give the name and formula of the ore of zinc.
ii) Write equation for the following steps in the extraction of zinc.
1) Roasting of the ore.
2) Reduction of the zinc compound which is the product of the reaction.
iii) What, in addition to a zinc compound, is put into the blast furnace?
iv) State one large scale use of zinc. (6)
c) All ammonium salts are decomposed on heating. What other property so ammonium salts have in common. ? (1)
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