FORM TWO CHEMISTRY NECTA 2013

THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATION COUNCIL

CHEMISTRY FTNA 2013

SECTION B

 (i) The apparatus used for grinding granular chemicals in the laboratory include:

  1. Crucible and watch glass
  2. Mortar and pestle
  3. Pestle and pair of tongs 
  4. Spatula and basin
Choose Answer :


 (ii)  The substances that can be used to extinguish fire are:

  1. Carbon dioxide and sand
  2. Carbon dioxide and sugar
  3. Nitrogen and sand
  4. Nitrogen and water
Choose Answer :


 (iii) Which of the following electronic configurations are of metals?

A. 2:8:1 and 2:5

B. 2:8:2 and 2:6

C. 2:8:3 and 2:8:8:7

D. 2:8:6 and 2:8:8:7

Choose Answer :


 (iv) When sugar is dissolved in water, a uniform mixture is formed. The resulting mixture is called a:

  1. Solute
  2. Solution
  3. Solvent
  4. Suspension
Choose Answer :


 (v) Flammable chemicals are those which:

  1. Burn skin
  2. Catch fire easily
  3. Explode
  4. Extinguish fire
Choose Answer :


 (vi) Which of the following can be classified as a renewable source of energy?

  1. Biomass
  2. Coal
  3. Coke
  4. Petroleum
Choose Answer :


 (vii) The part of Bunsen burner that controls the amount of air coming in is called:

  1. Air hole
  2.  Barrel
  3.  Collar 
  4.  Jet
Choose Answer :


 (vii) The part of Bunsen burner that controls the amount of air coming in is called:

  1. Air hole
  2.  Barrel
  3.  Collar 
  4.  Jet
Choose Answer :


 (ix) The simplest formula of a compound formed when combining 13g of aluminum and 17g of chlorine is:

  1. AlCl
  2. Al2Cl
  3. Al3Cl2
  4. AlCl3
Choose Answer :


 (x) The second step in the scientific procedure is:

  1. Data collection and analysis
  2. Data interpretation
  3. Experimentation and observation
  4. Hypothesis formation
Choose Answer :


2. Match each item in List A with a correct response in List B by writing its letter bellow the number of the corresponding item in the table provided.

LIST A

LIST B

(i)Ability of an atom to gain or attract electrons towards itself

(ii)Addition of oxygen to or removal of hydrogen from a substance

(iii)A substance which behaves in three states of matter

(iv)Bond formed between two atoms due to sharing of two electrons from each other.

(v)Combining power of an element

(vi)Liquids which form layers when mixed

(vii)Reddish brown coating on metals

(viii)Supports burning of substances

(ix) The number of electrons in the outermost shell

(x) Treatment and purification of water for human uses.

A. Chlorination

B. Covalent

C. Electronegativity

D. Electropositivity

E. Evaporation

F. Groups

G. Ionic

H. Kerosene and water

I. Oxidation

J. Oxygen

K. Reduction

L. Rust

M. Sugar and alcohol

N. Valency

O. Water

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3. (a) What do you understand by the following terms?

(i) Emperical Formula

(ii) Relative atomic mass

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(b)      A certain compound K contains 15.8% carbon and 84.2% sulphur. The molar mass of K is 76g/mol. Determine its:

(i)       simplest formula ... ......

(ii)     molecular formula .........

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4.(a) Define the following terms as applied in Chemistry:

(i)Flame

(ii)Bunsen burner

(iii)Laboratory

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(b)      List four properties of each of the following:

(i)       A luminous flame

(ii)     A non-luminous flame

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 Write the chemical formula for each of the following compounds:

(i)Sodium carbonate

(ii)Calcium nitrate

(iii)Ammonium chloride

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5. Calculate the percentage by composition of the underlined elements in the following compounds: (i) Na2S04

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(b)      Give the use of each of the following components which are found in the First Aid kit:

(i)       Plaster .........

(ii)     A pair of scissors (iii) Cotton wool ......... (iv) Gloves .........

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 Categorize the following changes as either chemical or physical:

(i)Freezing of juice in a bottle .........

(ii)Rusting of iron .........

(iii)Burning of wood .

(iv)Drying of wet clothes .........

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6.(a) Define the following terms:

(i)Chemistry

(ii)Element

(iii)Catalyst

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(b)      Give three differences between the following:

(i)       Compound and mixture

(ii)     Suspension and solution

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7.(a) The figure below shows the relationship among three states of matter. Name the processes involved in A, B, C and D.

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(b)      State the valency of each ofthe following atoms:

(i)       Aluminium             (ii) Neon

               (iii) Sulphur                             (iv) Potassium

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(c)       Give the chemical formula for the combination of the following sets of ions:

(i)       Mg2+, PO}(ii) Fe3+, soi-

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8.(a) Write a word equation for each of the following reactions:

(i)Calcium burns in Oxygen .........

(ii)Sodium reacts with water ... ... ...

(b)      What do you understand by the following terms?

(i)       Water treatment

(ii)     Water purification

(c)       Mention six uses of water in economic activities.

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9.Gas "L" has the following properties: it is highly flammable, readily combines with other elements, readily reacts with other chemical substances and is a strong reducing agent.

Name the gas L

(b)      What is the method used to collect gas in the laboratory? Give a reason.

Give four uses of gas L

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10.Mention four chemical properties of Oxygen.

(b)      Find the oxidation number of each of the underlined elements in the following: (i) KC103

(ii)

Use the IUPAC system to name each of the following chemical compounds:

    (i) Cuo                                 (ii) CaSO4

 (iii) HN03                               (iv) ZnC12

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