CHEMISTRY FIRST TERM EXAMINATION SS 3

                  

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

SUBJECT: CHEMISTRY                   

TIME: 3HRS           

  CLASS: SS  3

1.In a laboratory a student failed to uncover the reagent bottle filled with ethanol give reaction which occurred when the ethanol was exposed to air for shorter time before cover.

(a) C2 H 5 OH- CH 3 COOH (b) C 2 H 5 OH  =====- CH 3 C=O (c) C 2 H 5 OH === C 2 H 4 +H 2 O (d)C 2 H 5 OH =====CH 3 -O-CH 3

If the ethanol was exposed to air for very long time which of the above reaction will take place.

2. Which type of reaction occurs when soap is formed from fats?
   a. hydrolysis b. polymerization c. fermentation            d. substitution
   3. What is produced when ethanol is boiled with an excess of acidified potassium dichromate(VI)?
   a. ethane   b. ethanoic acid   c. ethene   d. ethyl ethanoate
   4. Which of the following is an ester?   a. pvc   b. soap   c. starch  d. terylene
   5. Starch can be broken down into smaller molecules by heating with a dilute acid. What is this type of reaction called?   a. cracking   b. fermentation   c. hydrolysis  d. reduction
   6. A margarine is described as ‘high in polyunsaturates’. What does this type of margarine contain?
   a. long chain alkane molecules   b. many alkene molecules joined by addition polymerization
   c. molecules containing many C=C bonds  d. polymer molecules with -O=C-N-H- linkages
   7. Vinegar is a solution of ethanoic acid made by the reaction of ethanol with air. Which gas in air takes part in this reaction?   a. carbon dioxide   b. nitrogen  c. oxygen  d. water vapour
   8. All the following sample will undergo hydrolysis with dilute acid except (a) fructose (b)

Sucrose (c) lactose (d) Maltose

9. Dehydration of carbohydrate by concentrated H 2 SO 4 will give (a) black residue of carbon (b)the components monosaccharides (c) sooth of coal (d) a yellow – brown known as caramel..
10. Which polymer has the same type of linkage between its monomers as in a fat?
    a. polyamide b. polyester       c. protein     d. starch
    11. Nylon (a polyamide) and Terylene (a polyester) are both man-made fibres. Which type of reaction is used to produce both of these polymers?
    a. addition      b. condensation       c. fermentation    d. hydrolysis
    12. Part of a polymer molecule has the following structure.  -CH₂-CH₂-CH₂-CH₂-CH₂-CH₂–
    From which substance is this polymer made?    a. C₂H₄  b. C₂H₆   c. C₃H₆  d. C₃H₈
    13.      The number of naturally occurring α-amino acids is about   a) 10    b)  50    c)   40   d) 20
11. Which one of the following structures represents the peptide chain?
12. Bakelite is    a)      addition polymer   b)      elastomer   c)    thermoplastic    d)     thermosetting

16      The repeating units of PTFE is

1. a)      Cl₂CH-CH₃ b)      F₂C = CF₂ c)      F₃C-CF₃    d)     FCIC = CF₂
2. The inter-particle forces between linear chains in Nylon-66 are
3. a)      H-bonds b)      covalent bonds c)      ionic bonds   d)     unpredictable.
4. Nylon-66 is a polyamide of
5. a)      viny1chloride and formaldehyde b)      adipic acid and methyl amine
6. c)      adipic acid and hexamethylene diamine d)     formaldehyde and malamine.
7. Which of the following is not a condensation polymer?
8. a)      Glyptal b)      Nylon-66 c)      Dacron    d)     PTFE.
9. The monomer of PVC is a)      ethylene   b)      tetrafluoroethylene   c)      chloroethene
10. d)     none of the above.
11. Which of the following polymers is, a copolymer? a)      Polypropylene b)      Nylon-66
12. c)      PVC d)     Teflon
13. Which of the following polymers is a homopolymer? a)      Bakelite   b)      Nylon-66
14. c)      Terylene d)     Neoprene.
15. Bakelite is obtained from phenol by reacting with a)      ethanol   b)      methanal
16. c)      vinyl chloride d)     ethylene glycol.
17. Soft drinks and baby feeding bottles are generally made up of
18. a)      polyester b)      polyurethane c)      poly urea   d)     polyamide   e)      polystyrene.
19. (-NH(CH₂)₆-NHCO(CH₂)₄CO-)_n is a
20. a)      homopolymer b)      copolymer c)      addition polymer   d)     thermosetting polymer.
21. Which is not a polymer? a)      Sucrose   b)      enzyme   c)      Starch   d)     Teflon

 

27. Fats and oils are
28. a)      monoesters of glycerol b)      diesters of glycerol c)      triesters of glycerol
29. d)     diesters of glycol
30. Which of the following is an example of aldohexose?
31. a) Ribose b)      Fructose  c)      Sucrose   d)
32. Which disaccharide is present in milk? a)      Maltose   b)      Galactose  c)      Sucrose
33. d)
34. Which of the following is a ketohexose ?
35. a) Fructose b) Maltose c)      Glucose d)
36. The linkage that holds monosaccharide units together in a polysaccharide is called
37. a) peptide linkage b) glycoside linkage c)      ester linkage d)     ionic linkage.
38. The impurities associated with’ the ore after mining are collectively called

(a) flux                            (b) slag (c) minerals                  (d) gangue.

33. Which of the following processes does not result in the formation of both carbon dioxide and water? a. addition of a dilute acid to a carbonate b. burning ethanol   c. burning methane
    d. heating crystals of hydrated sodium carbonate
    34. Which of the following metals can be extracted by smelting?

(a) Aluminium             (b) Magnesium (c) Iron                        (d) None of these.

35. In the froth-floatation process for benefication of the ores, the ore particles float because

(a)       they are light (b)      their surface is not easily wetted by water (c)       they bear

electrostatic charge (d)      they are insoluble.

36. Synthetic rubber is produced from but-1,2-diene by (a) cracking (b) hydrogenation (c)

Polymerization (d) Vulcanization

37. In the extraction of iron in the blast furnace, of the following is used to remove earthly

impurity from the ore? A. Air b. Carbon (ii)oxide c. Coke d. Limestone e. Magnetite

38. Aluminium is extracted by (a) electrolysis of the purified ore (b) froth floatation of the

smelted ore (c) reduction of the ore with coke in a furnace (d) roasting the ore in excess supply

of air

39. Which oxide can be reduced to the metal using carbon? a. calcium oxide b. magnesium oxide
    c. sodium oxide d. zinc oxide
    40. Alkali metals…………….. a. forms covalent bonding with the halogens  b.have theIr melting point decrease down the group           c.forms oxides when reacted with water

d.have their reactivities decrease down the group

41. Most reactive metals are extracted from their ores through electrolysis except (a) Na (b) Al

(c) Ca (d) Mg

42. Calcium reacts directly with nitrogen to form a.Ca 3 N 2 b.Ca 2 N 3 C.Ca 3 N 2 d.Ca 3 N
43. The great affinity of aluminium for oxygen at high temperatures is employed in the

a.electrolytic process b. thermit process c. Haber process d. lead chamber process

1. Solvay process
2. When heated, solid X gives off a gas which turns limewater milky. The residue reacts with dilute acid and also with aqueous alkali. What is X?
   a. copper(II) carbonate b. magnesium carbonate c. sodium carbonate    d. zinc carbonate

45 . The molecular formula of Sucrose is

1. CH₂O B. C₆H₁₂O₆ C. C₁₂H₂O₁₁   D. CH₃COOH

46.Steel is an alloy of iron containing only a. carbon b. carbon and other elements depending on

the strength desired. C. Carbon and nickel d. Carbon and chromium

47. Iron is paramagnetic because
48. its orbitals have few unpaired electrons b. its orbitals have only paired electrons
49. iron has large number of unpaired electrons d. it is ferromagnetic
50. Zinc is not regarded as a transitional metal even though it is a d-block element because
51. it has no electron in 3 d-block b. it has all 3 d-orbitals completely filled      c.it blends with

other neighbouring elements d. it does not form complex ion like others.

49. Which of the following is a typical property of transition metals?
    a. they form colored compounds b. they have low densities c. they have low melting points
    d. they react with cold water to give hydrogen
    50. . In the manufacture of iron by the blast furnace, which are the main gases that escape from the top of the blast furnace?
    a. carbon monoxide, carbon dioxide, hydrogen   b. nitrogen, carbon dioxide, carbon monoxide
    c. nitrogen, oxygen, steam    d. oxygen, carbon dioxide, sulfur dioxide

 

THEORY: Attempt three questions from this section.

1a.Distinguish between esterification and saponification reactions of organic compounds.

The structural formula of an ester is

 

1. Write the structural formula of the corresponding alcohol and the acid.

 

c.Using chemical equations only, describe 2 ways of preparing ethanoic acids.

d.With chemical equations only ,show the reactions of Alkanoic acids with the following.

NaHCO₃               ii. Zn

2a.What is the basic structure of a synthetic detergent molecule?

b.Draw structures of glycine and alanine, and give their IUPAC names.

1. Explain briefly:
2. primary structure of proteins
3. denaturation of proteins
4. Give an example of aldohexose and an aldotriose.
5. Give the structure of sucrose

3a. What are the hydrolysis products of?                i.            sucrose

1. lactose

b.How would you prepare caustic soda from washing soda? Give the equation of reaction.

1. How does sodium hydroxide react with metallic zinc and aluminium respectively? Give the equations of the reactions.

d.Describe the four characteristics of the transition metals with examples.

4a.  Explain the following terms with examples:   i.    Polyester   ii     Polyamide

b.How does vulcanised rubber differ from natural rubber?

1. Classify the following polymers into addition polymers and condensation polymers.
2. i)      Terylene ii)      Nylon-66 iii)      Neoprene         iv)     Teflon.
3. What is the difference between homopolymer and co-polymer? Give one example each.

5a.Describe how pure aluminium oxide is obtained from its ore.

b.Why is it possible to store trioxonitrate(v) acid in aluminium containers?

1. Name the most pure form of iron.

d.Give equations for the reactions taking place in different regions of the blast furnace during extraction of iron from haematite.

e.What are the components of    (i) stainless steel and duralamin