SS 2 Chemistry Third Term Examination

   THIRD TERM

Examination malpractices may lead to a repeat of the subject or suspensions don’t be involved.   

SUBJECT   CHEMISTRY       

CLASS: S. S. S TWO              

DURATION 2 HR

  1. Water is temporarily hard because it contains

a.CaSO4   b.MgSO c .Chlorine   d. Ca(HCO3)2

  1. The following are characteristics of colloids except 
  2.   tyndal effect on light beam   b. solid phase are removed by dialysis   c. colloidal particles are larger than that of suspensions
  3. colloidal particles are separated using parchment membranes.
  4. One of these is not a water pollutant
  5. petroleum   b. domestic liquid and solid waste c. industrial effluents   d. Biodegradable chemicals
  6. 144 g of KCl  dissolved in 1dm3 of water  at 90°C in the presence of excess crystals of KCl. Calculate the solubility of KCl at  this temperature.(K=39,Cl=35.5)a.0.89moldm-3  b.1.93moldm-3    c.1.75 moldm-3    d.1.5moldm-3
  7. What is the volume occupied by 2 moles of ammonia at S.T.P?(a) 44.8dm-3   B. 22.4dm-3     C. 11.2dm-3(d) 5.6dm-3
  8. Consider the neutralization reaction represented by the following equation: Na2CO3 + 2HNO3 → 2NaNO3 + H2O + CO2. The stoichiometric ratio of acid to base is (a) 2:2    B. 2:1     C. 1:2     D. 1:1
  9. The   shape of water molecule is  (a) angular    b. tetrahedral   c. pyramidal   d. linear
  10. The volume occupied by0.4g of hydrogen gas at S.T.P. is (H=1.00,Molar volume at S.T.P =22.4dm3).

a.2.24dm3   b.4.48dm3     c.22.4dm3   d.8.96dm3

  1. Which of the following will not decolourise bromine water?

a.C2H6    b.C2H4  c.C3H4   d.C3H6

  1. The gas that can be best collected by downward displacement of air (a) chlorine (b) carbon(iv)oxide  (c) sulphur (iv)oxide  (d) ammonia
  2. Which of the following properties of elements decreases generally across a period in the periodic table?   (a) electronegativity  (b) electron affinity  (c) atomic radius  (d) ionization energy.
  3. If the electron configuration of an element is 1s22s22p63s23p6,it shows that  it is a:

(a)group II element (b) noble gases ( c) group V element  (d) group II elements

13.Cr2O-2+ 14H+ + xe           2Cr3+ + 7H2O

The number of moles(x) of electrons in the above half cell equation is: (a) 2  (b) 4  (c) 7 (d) 6

  1. the volume occupied by 0.4g of hydrogen gas at STP is (H=1.00, molar volume at STP =22.4 dm3)

(a) 2.24  dm3   (b) 4.48dm3  (c) 22.4dm3 (d) 8.96 dm3

  1. A measure of degree of disorderliness in a chemical system is known as:    (a)enthalpy   (b) free energy  (c) entropy  (d) activation energy
  2. H2(g)+ x2(g)           2HX(g) ΔH=positive. In the above reaction,a decrease in temperature will:

(a) decrease the concentration of HX 

(b) favour the forward reaction 

(c) favour the yield HX

(d) have no effect on the equilibrium position

  1. 3Fe(s)+4H2O(g) Fe3O4+ 4H2(g) .The equilibrium constant K of the reaction above is represented as:

(a) [H2]4/[H2O]4    (b) [Fe]3 [H2O]4 /[Fe3O4] [H2](c)[Fe3O4][H2]4/[Fe]3[H2O]4        (d)[H2]4/[H2]4

  1. What is the quantity of electricity produced when a current of 0.5 A is passed for 5 hours 45 minutes (F=96500)?  (a)0.11F    (b)0.22F  (c) 0.12F (d) 1.1F
  2. The oxidation number of phosphorus in PO43- : (a) +1   (b) +3 (c) +4  (d) +5  
  3. Compounds that exists in two or more different structural forms which also differ in chemical or/and physical properties but possess the same molecular formula this is said to exhibit. 

(a) Isotopy (b) Isomerism (c) Polymerism (d) allotropy

  1. Consider the reaction represented by the following equation:

H-CC-H  H2 H2Y; X and Y respectively are (à) ethene and ethane B. ethane and ethene (c) ethyne and ethane D. ethane and propene

  1. Compound N reacts with sodium metal to produce a gas that gives a “pop” sound with a burning splint. N also reacts with ethanol to give a sweet smelling liquid. Compound N is an ká) alkanol    B. alkanoate    C. alkanealkanoic  acid
  2. A solutions of sodium trioxocarbonate (iv) contains 10.6g in 250cm3 of solution. Calculate the concentration of the solution. [Na2CO3 = 106.0]
  3. 0.4mol dm-3   B. 1.0moldm-3
  4. 10.6moldm-3   D. 25.0moldm-3

   

  1. The IUPAC name of the compound 

                                CH3        CH3  

 

                     CH3 –    CH  –  CH – CH3

2,3 – dimethyl pent – 2,3 – one

3,4 – dimethyl pept – 2 – one

2,3 – dimethyl butane

 3,4 – dimethyl pentene

  1. The alkanoate  CH3CH2COOC2H5 is the product of the reaction between:

(a) ethanoic acid  and ethanol

(b) ethanoic acid and propanol

(c) propanoic acid and ethanol 

(d) propanoic acid and propanol

  1. Filling the burette for titration involves these except (a) wash with water   b. rinse with acid   c. eject air bubbles    d. read at eye level

27.The change from the degree of unsaturation to saturation is called ——-reaction.

 a .substitution  b. addition   c. saturation  d. fermentation.

  28.A carbon hydrocarbons consists of 92.35% carbon. If its vapour density is   39,determine its molecular formular.a.C3Hb.C6H6  c.CH  d.C9H9.

29.What is the IUPAC  name of CH3CHClCH2CH2CH3?

  1. 2- bromopentane   b.2.chloropentane   c.2-chlorobutane   d.2-dimethyl pentane

30.What is the general reaction that  Alkanes, Alkenes and Alkynes undergo.

a.substitution   b.combustion   c.addition   d.fermentation

  1.   An organic compound decolorized acidified KMno4 Solution but failed to react with ammonia cal silver nitrate solution. The compound is likely to be (a) Alkyne (b) Alkan one (c) Alkene (d) Alkanol

32.Why does ethanol taste sour when exposed to air (a) it undergoes reduction undergoes hydrolysis and turns to acid (d) it undergoes oxidation and changes to acid.

33.When water drops are added to calcium carbide in a container and the gas produced is passed through a lighted jet, the resultant flame is called an (a) oxyathlyene flame (b) oxyethyne flame (c) oxyhydrocarbon (d) oxyacethylene flame

34.Which of the following can be written as cylohydrocarbon.

 (i) C6H6 (ii) C2H4 (iii) C3H8 (iv) C4H8

(a)I and iv (b) I and iii (c) ii and iv (d) I, iii and iv

35.A palm wine seller stoppered a bottle of his palm wine in his stall an after a few hours the bottle exploded. Which of the following equations represent the reaction that occurred? (a) 2C6H12O6 enzyme C12H22O+ H2Ovapour 

(b)2C6 H12O6 enzymes   2C2 H5 OH + 2CO2    

 © C2H5OH   ————-CH2=CH2(g) + H2O

(d) C6 H12O6 enzymes C2 H5 OH + CO

36.The reaction between C2 H4 and the halogen is called _____________ reaction (a) oxidation (b) substitution (c) addition (d) Polymerization

37.The mixing or blending of two or more atomic orbital  is know as _______________ (a) Polymerization (b) condensation (c) Hybridization (d) esterification.

  1. The IUPAC name of the simplest alcohol is

(a)Methanol(b)  ethanol (c)ethyl alcohol (d)methyl alcohol

39.If an organic compound has the following composition , carbon 37.4% and hydrogen 12.4% has empirical formal of C=12 ,H=1,and O =16(a) C2H4O (b) C4 H8 (C) CH4O (d) C2 H4

40.Which of the following organic compound structure is the most soluble in water? (a) CH3-O-CH3 (b) CH3CH2OH (c) CH2=CH2 (d)CH3CH3

  1. Propan-2-01 undergoes oxidation reaction to form (a) propan-2-al 

(b) Propanioc acid (c) Butan-2-one (d) propanone

42.Which of the following structure will produce sooth or smoke most when burning ________ (a) C4H10 (b) C2H6 (c) C3H4 (d) CH4

43.In a laboratory a student failed to uncover the reagent bottle filed with ethanol, give the reaction which occurred when the ethanol was exposed to air for shorter time before cover. (a) C2H5OH  0 CH3COOH (b) C2H5OH 0            CH3C=O (c)  C2H5OH ConcH2SO4    C2H4+H2O (d) C2H5OH          CH3-O-CH3

  1. Compounds that exists in two or more different structural forms which also differ in chemical or/and physical properties but possess the same molecular formula this is said to exhibit. 

(a) Isotopy (b) Isomerism (c) Polymerism (d) allotropy

45.The reversible reaction of esterification is known as (a) Hydrolysis (b)Saponification (c) hygrolysis (d) Transformation

46.Example of secondary alcohol is (a) Ethanol (b) Propan-2-0L (c)  2-methyl propan-2-0L (d) Butan-1-0L

47.Tertiary alcohol is an example of  (a) monohydric (b) Trihydric (c) Dihydric (d) Polyhydric

48.What is the catalyst used in  reaction below. CH4+Cl2       CH3Cl +HCL

Finely divided Nickel (b) Sunlight 

(c) Conc. H2SO4 (d) Platinum

  1. If an excess of liquid hydrocarbon is poured into a jar of chlorine and the       sealed jar is then exposed for several hours to bright sunlight, all the chlorine gas is consumed. The hydrocarbon is said to have undergone. (a) a polymerization reaction (b) an addition reaction (c) a substitution reaction (d) a reduction reaction
  2. The function of conc . H2SO4 in the esterification of ethanoic is to 

(a) serve as a dehydrating agent (b) prevent any side reaction (c) act as a catalyst (d) serve as an oxidizing agent.

THEORY

1a.     Give the IUPAC names of the structures below 

(i) CH3CHCH2 CH2CH2CH

 

     (a) CH3    

 (ii) CH3 – CH – CH2 – CH – CH2 – CH3

     

         CH3                        C2H5

(iii)  CH3C = CCHCH3   

                                 

                        CH3

  (iv) CH3CH2CH2CH2CH = CH2

          

b.Write the structural formulae for these compounds (i) C is –pent – 2 – ene  

 (ii) 2 – methylpent – 2 –ene (iii) 2,2,3 – trimethylbutane (7mks)

  1. Using chemical equations, describe two ways of removing each of the following hardness of water. i. temporary hardness of water
  2. permanent hardness of water  ( 6mks)
  3. Describe the origin of hardness.(2mks)

2a.The solubility of KNO3 at 200C was 3.00mol/dm3. If 67.0g of KNO3 was added  to 250cm3 of water and stirred at 200c,determine whether  the solution is saturated or not with reasons.(4mks)

  1. Define the following terms
  2. saturated solution   ii. supersaturated solution  ( 4mks)
  3. Classify the following as colloids, suspension  ,aerosols and true solution.

gel, clay, milk, hair cream ,smoke,fog,CuSO4,NaCl   (4mks)

  1. The solubility of copper(ii) tetraoxosulphate  vi at 850c is 60g in 100g and at 150c  is 18.8g in 100g.If 120gof solution saturated at 850c are cooled to150c,what mass of copper(ii)sulphate crystals would be deposited?(3mks)

3a.Oxygen gas is sometimes prepared in labs by the thermal decomposition of potassium chlorate(KClO3).The balanced equation is as follows:

2KCl03-2KCl(s)+302(g).

If 5.150g of KClO3 decompose, what volumes of 02 would be obtained at S.T.P?(K=39,Cl=35.5,O=16).(4mks)

  1. If 0.8 g of gas z occupies 0.56 dm3 at s.t.p. calculate its relative molecular mass.(molar volume of gas is 22.4dm3).(3mks)
  2. Write the equation of combustion reaction of a named alkene.(4mks)
  3. Using chemical equations only, highlight the industrial preparation of ethanol by fermentation process.(4mks)
  4. a .A solution of trioxonitrate (v) acid contained 0.67g  in 100cm3. 31.0cm3 of this solution neutralized 25cm3 of a sodium trioxocarbonate (iv) solution. Calculate the concentration of the trioxocarbonate (iv) solution in mol/dm3.(HNO3=63,Na2CO3=106).(4mks)
  5. Two hydrocarbons x and y were treated separately with acidified potassium tetraoxomanganate(vii) solution. x decolorized the solution and y did not. Which  of x and y will undergo
  6. substitution reaction
  7. both addition and substitution reaction (3mks)
  8. Mention two compounds of benzene and draw their structure.(5mks)
  9. Why is it that an hydrocarbon give a precipitate with ammoniacal AgNO3 whereas some homologues do not.(3mks)

5a. What happens when few drops of Conc.H2SO4 is added to solution of ethanoic acid and Ethanol? Write the equation of reactions.(4mks)
b. Why is the conversion of ethanol to ethanoic acid an oxidation reaction?( 2mks)
c.  ‘‘Saturated hydrocarbons burn with a blue flame while unsaturated hydrocarbons burn with a sooty flame’’. Why? (4mks)
d.How would you bring about the following conversions? Name the process and write the reaction involved.  (a) ethanol to ethene (b) propanol to propanoic acid.(5mks)