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Lesson 110: Paper 2 (Section A)

Name : _____________________________________

Class : _____________________________________Date : _____________________________________

A. Structured Questions.

1.

Table 1

Table 1 records the information about elements V, W, X, Y, and Z.

a) Write the electron arrangement for element W.Ans:

b) (i) What type of bond is formed between X and Z?Ans:

(ii) Write the chemical equation for the reaction between X and Z.Ans:

c) (i) Which element is a noble gas?Ans:

(ii) State one use of the element in c)(i)Ans:

d) (i) How many neutrons does element W has?Ans:

(ii) Which element loses an electron to have the same electron arrangement aselement W?Ans:

(iii) Why does element d)(ii) lose an electron to have the same electron arrangementas element W?Ans: .

e) Name 2 elements belong to the same group in the Periodic Table?Ans:

Element Proton Number Nucleon NumberV 3 7W 18 41X 8 16Y 8 17

Z 19 40

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2.

Figure 1

Figure 1 shows a flowchart to identify metal compound A

a) Identify A, B, C and D Ans:

b) (i) Write the observation when aqueous sodium hydroxide is added to colourlesssolution D in excess.

Ans: .

(ii) What do you observe at Y?Ans:

c) Colourless solution D is a soluble salt and exists as crystals in solid state two physicalcharacteristics of crystals.Ans:

d) Metal compound A is an of insoluble salt. What is the name of the reaction for the

preparation of insoluble salts?Ans:

Colourless gas B turnslime water milky.

Solid C is yellow whenhot and white when itcools down.

Metal compound A

Y Colourlesssolution D

b i)

heat

+ HCl

Dilute nitric acid andsilver nitrate solution

Sodium hydroxide

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3.

Figure 2

Answer the following questions based on figure 2.

a) P is an alkali metal with electron arrangement 2.8.1. Where is P in the Periodic Tableon figure 2.Ans:

b) State two special characteristics of element X.Ans:

c) State the changes in the following properties for elements in Period 3 from W to Z(i) atomic radius

Ans:

(ii) electronegativityAns:

d) (i) Write the chemical equation for the reaction between W and V.Ans:

(ii) State how the electrons are transferred during the reaction between W and V.Ans:

.

e) Element U can combine with element Y to form a compound.(i) Write the chemical formula of the compound formed.Ans:

(ii) Predict the melting and boiling points for the compound formed in f(i).Ans:

U VP W Y Z

X

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4.

Figure 3

Figure 3 shows the electrolysis of an aqueous potassium sulphate solution using carbon

electrodes.a) Why is carbon used as the electrodes?

Ans:

b) Name the ions present in the potassium sulphate solution?Ans: .

c) What are the ions attracted to the anode and the cathode during the electrolysisprocess?Ans:

d) (i) Name the ion discharged at the cathode?Ans:

(ii) Explain your answer in d)(i).Ans:

e) (i) What is observed at the anode?Ans:

(ii) Write the half equation for the reaction that occurs at the anode.Ans:

f) (i) Name the gas collected at the anode.Ans:

(ii) State the test for the gas collected at the anode.Ans:

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5.

Figure 4

The apparatus in figure 4 is a set up to test the solubility of hydrogen chloride gas in waterand methylbenzene

a) Describe the solubility of hydrogen chloride in water?Ans:

b) State the observation when this aqueous solution of hydrogen chloride is tested with:(i) litmus papers.Ans:

(ii) magnesium.Ans:

c) Write a balanced equation for the reaction in b)(ii)Ans:

d) Predict what would happen to the litmus papers when the experiment is repeated withmethylbenzene replacing water.Ans:

e) Explain your answer in d)Ans:

f) Name the particles present in:(i) hydrogen chloride in waterAns:

(ii) hydrogen chloride in methylbenzeneAns:

g) Explain why an inverted filter funnel is used in Figure 4?Ans:

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6.

Figure 5

Figure 5 shows the set up for an experiment to prepare copper(II) nitrate salt.

a) Name acid Y?Ans:

b) Write an equation for the reaction that occurs in the beaker.Ans:

c) How do you ensure copper(II) oxide is in excess?Ans:

d) Why is excess copper(II) oxide added?Ans:

e) Name the type of reaction involved in c.Ans:

f) Suggest two other copper compounds that can be used to replace copper(II) oxide.Ans:

g) Product of the reaction in the beaker is filtered. The filtrate is heated until one-third of its original volume is left, and then left to cool. Salt crystals obtained are dried.(i) Why is the filtrate heated?Ans:

(ii) Why is one-third of the filtrate left during evaporation?Ans:

h) Name the process that can be used to purify the copper(II) nitrate salt.Ans:

(i) Suggest how would you convert copper(II) nitrate back to copper(II) oxide?Ans:

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7. Contact Process is used in the manufacture of a certain chemical S in the industry. Thediagram below shows the steps involved.

Chamber P+ NH 3

a) Name the substances:Ans:

b) Write the chemical equation for the reaction that takes place in Chamber P.Ans:

c) State the necessary conditions for the reaction that takes place in Chamber P.Ans:

d) Substance A obtained in Chamber P is dissolved in Q, but not in water.Give a reason for not using water.Ans:

e) Substance S will react with ammonia to form Z. Write the chemical equation to showthe reaction.Ans:

f) Suggest one important use of Z.Ans:

Sulphur dioxide + oxygen Substance Y is added

Substance ASubstance A

dissolved in Q Substance RSubstance

S

Z

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8.

Figure 6

Figure 6 shows the apparatus used to determine the empirical formula of copper(II) oxide.

a) (i) Why is hydrogen gas allowed to flow through the combustion tube before the oxide is

being heated?Ans:

(ii) The flow of hydrogen gas is continuous throughout the whole activity, until the hotcopper cools down to room temperature. Why is hydrogen gas allowed to flowcontinuously even after the heating has stopped?Ans:

(iii) How would you ensure that all the copper(II) oxide has been reduced to copper.Ans:

b) Table 1 below shows the result of this experiment

Mass/gCombustion tube + porcelain dish 20.5Combustion tube + porcelain dish + copper oxide 40.5Combustion tube + porcelain dish + copper 36.5

Table 1

Determine the empirical formula of copper oxide.[Relative Atomic Mass:Cu,64; O,16]Ans:

c) Write the equation for reaction which occurred in the combustion tube.Ans:

d) Suggest a method to prepare hydrogen gas for the above experiment.Ans:

e) Name a substance used to dry the prepared hydrogen gasAns: