NAME…………………………………………………………………. INDEX NO…………………………………………………………

SCHOOL……………………………………………………………………………………………………………………………………….

SIGN……………………………………………………………………………………………..…DATE ……………………………

233/1

CHEMISTRY

PAPER 2

2 HRS

JULY 2019

CHANIA ZONEJOINT INTER-SCHOOLS EVALUATION TEST

(CZJISET)INSTRUCTIONS TO CANDIDATES

[a]Answer ALL questions in the spaces provided in each question.

[b] Mathematical tables and electronic calculators may be used for calculations.

[c]All working must be clearly shown where necessary.

FOR EXAMINERS ONLY

QUESTION MAXIMUM SCORE CANDIDATES SCORE1 112 113 84 125 126 157 12Total

1

1. The diagram below shows spots of pure substance A,B and C on a chromatography paper. Spot D is that of a mixture.

After development ,A,B and C were found to have moved 8cm,3cm and 6cm respectively D was separated into two spots which had moved 6cm and 8cm.

On the diagram

[i][a]Label the baseline (origin). [1mk]

[b]Show the positions of all the spots after development. [3mks]

[ii]Identify the substances present in the mixture D. [2mks]

[b]Describe how solid ammonium chloride can be separated from a solid mixture of ammonium chloride and anhydrous calcium chloride. [2mks]

2

[c]The table below shows liquids that are miscible and those that are immiscible.

liquid L3 L4L1 Miscible MiscibleL2 Miscible Immiscible

Use the information given to answer the questions that follow

[i]Name the method that can be used to separate L1 and L3 from the mixture of the two.[1mk]

[ii]Describe how a mixture of L2 and L4 can be separated. [2mks]

2. An ore is suspected to contain mainly iron. Describe a method that can be used to confirm the presence of iron in the ore. [3mks]

[b]Excess carbon (ii) oxide gas was passed over a heated sample of an oxide of iron as shown below. Study the diagram and answer the questions that follow.

3

Mass of empty dish=10.98g

Mass of empty dish +oxide of iron=13.30g

Mass of empty dish +residue=12.66g

[i]Determine the formula of the oxide of iron. (Relative formula mass of iron oxide=232, Fe=56.0, O=16.0) [3mks]

[ii]Write an equation for the reaction which took place in the dish. [1mk]

[c]Corrosion is a destructive process in which iron is converted into hydrated iron (III) oxide. State:

[i]Two conditions necessary for rusting to occur. [1mk]

[ii]One method used to protect iron from rusting. [1mk]

[d]Explain why it is not advisable to wash vehicles using sea water. [2mks]

3.[a]State the Hess’s law. [1mk]

4

[b]The enthalpies of combustion of calcium, carbon and decomposition of calcium carbonate are indicated below:

C[s]+12O [2][g] → CaO[s]: ∆H =-635KJmol-1

C[S]+O2[g] → CO2[g] ∆H =-394KJmol-1

Enthalpy of decomposition of Ca CO3=+178KJmol-1

[i]Draw an energy cycle diagram that links the enthalpy of formation of calcium carbonate to enthalpies of combustion of calcium, carbon and decomposition of calcium carbonate. [2mks]

[ii]Determine the enthalpy of formation of calcium carbonate. [2mks]

[c]Some average bond energies are given below.

Bond energy in KJmol-1

C-C 348

C-H 414

Cl-Cl 243

C-Cl 432

H-Cl 340

Calculate the energy change for the reaction below. [3mks]

5

C2H6(g)+Cl2(g) → CH3CH2Cl(g)+HCl(g)

4. Use the standard electrode potentials for A, B, C, D andF given below to answer the questions that follow.

Eθ (Volts)

A2+[aq] +2e ⇋ A[s] -2.90

B2+[aq]+2e ⇋ B[s] -2.38

C+[aq]+2e ⇋ 1

2C2[g] 0.00

D2+[aq]+2e ⇋ D[s] +0.34

12F2[g]+e- ⇋ F-

[aq] +2.87

[I]Which element is likely to be hydrogen? Give a reason for your answer. [2mks]

[ii]What is Eθfor the strongest reducing agent? [1mk]

6

[iii]Calculate the e.m.f of the cell that would be formed when half cells of Band D are combined.[1mk]

[b]Aqueous copper (II) sulphate was electrolysed using the set shown below.

[i]When the switch was closed, a gas was produced at electrode B.Which electrode is the anode?[1mk]

[ii]Write the half equation for the reaction at electrode B. [1mk]

[iii]What happens to the pH of the electrolyte above during electrolysis? Explain. [2mks]

7

[i]If carbon electrode were replaced with copper electrodes in the cell above, write the equation for the reaction that would occur at the anode. [1mk]

[c]During electrolysis of copper [II] sulphate using copper electrodes, a current of 0.2 ampheres was passed through the cell for 5 hours. Determine the change in mass of the cathode that occurred as a result of the electrolysis process. (Cu=64, IF=96500C). [3mks]

5. The grid below is part of the periodic table. Letters are not actual symbols. Study it and answer the questions that follow.

[i]Give the letters representing atoms that can form a singly charged ion. [1mk]

[ii]Identify the most electronegative element in the grid. Explain. [2mks]

8

[iii]Identify the strongest reducing agent. [1mk]

[iv]Write the formula of the most stable compound formed when J and K react. [1mk]

[v]Give the name of the type of bond in the compound formed in (IV) above. [1mk]

[vi]Give the chemical family name of L and M. [1mk]

[vii]Write the ionic equation for the reaction in which gas L is bubbled through a solution with ions of M. [1mk]

[viii]Element P is an alkaline earth metal and belongs to periodic 2.Indicate its position on the grid.[1mk]

[b]Use the information in the table below to answer the questions that follow.

ELEMENT ATOMIC NUMBER MELTING POINT(°C ¿Q 11 98R 12 650S 14 1410T 17 -102

9

U 18 -189V 19 64

Give a reason why the melting point of

[i]Q is higher than of V. [1mk]

[ii]R is higher than Q. [1mk]

[iii]S is the highest [1mk]

6. Study the flow chart below and answer the questions that follow.

[a][i]Name the type of reaction in the following steps.

10

I Step III [1mk]

IIstep IV. [1mk]

[ii]Name the important reagents and conditions in

Step1: Reagent [1mk]

Condition [1mk]

Step II: Reagent [1mk]

Condition [1mk]

Step V: Reagent [1mk]

Condition [1mk]

[b][i]Write a balanced equation for the reaction taking place in

Step VI. [1mk]

Step VII [1mk]

[ii]Give the systematic name of liquid X and substance L

Liquid X [1mk]

11

Substance L [1mk]

[c][i]If the relative molecular mass of compound formed in step III is 42 000, determine the value of n in the compound. (C=12.0, H=1.0). [2mks]

[ii]State one disadvantage of continued use of items made from the compound formed in d (i) above.[1mk]

7. Use the flow chart below to answer the questions that follow.

12

[A]Name:

[i][a]Substance C [12mk]

[b]Compound K [12mk]

[ii]Write the formula of compound K. [1mk]

[B]The following set-up is used to prepare nitric [v] acid in the laboratory.

[i]All the apparatus used during preparation of nitric [v]acid are made by glass. Give a reason.[1mk]

13

[ii]Name solid Q. [1mk]

[iii]Give a reason why it is possible to separate nitric (v) acid from the sulphuric (VI) acid used as one of the reagents. [1mk]

[vi]Give 2 uses of Nitric (v) acid [2mks]

[c]In an experiment 1200cm3 of ammonia gas measured at r.t.p reacted completely with copper (ii) oxide. Calculate

[i]The mass of copper formed given the formula of reaction. [3mks]

3CUO[s]+2NH3 [g] → 3CU [s]+3H2O[l]+N2[g]

[ii]The volume of Nitrogen gas formed N=14, H=1.0, O=16.0) [2mks]

CU=64MGV at r.t.p=24 dm3.

14

15