FORM TWO CHEMISTRY NECTA 2015

THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATION COUNCIL

CHEMISRY FTNA 2015

(i) Which of the following is the most correct statement about hypothesis?

  1. A fundamental concept or theory
  2. A possible explanation to the problem.
  3. An important statement of a research conclusion 
  4. A stage in data interpretation.
Choose Answer :


(ii) Which of the following is not among the gases composing air?

  1. Noble gases
  2. Carbon dioxide
  3. Nitrogen
  4. Hydrogen
Choose Answer :


(iii) When an atom loses or gains electron, it becomes:

  1. An ion 
  2. An anion
  3. A cation 
  4. A charged ion
Choose Answer :


(iv) A change from gaseous state to solid state without passing through a liquid state is called:

  1. Deposition 
  2. Sublimation
  3. Condensation 
  4. Solidification
Choose Answer :


(v) What is the type of a fire associated with electrical equipment?

  1. Class E 
  2. Class C
  3. Class F 
  4. Class B
Choose Answer :


(vi) Which among the following are the two processes involved during distillation?

  1. Evaporation and sublimation 
  2. Evaporation and crystallization
  3. Evaporation and condensation 
  4. Evaporation and decantation
Choose Answer :


(vii) Which of the following set of nuclide notation represents isotopes? 

  1. 18 X 16 X 19
  2. 18 X 18 X X 
  3.  16 x 18 x 1890x 
  4.  16 X 1789x,
Choose Answer :


(viii) The chemical used to test the presence of water in a substance is:

     A. Cobalt Il oxide                        B. Cobalt 111 oxide

    C.Cobalt chloride  D. Copper Il chloride

Choose Answer :


 (ix) When a burning fuel produces blue colour it means there is:

   A.adequate supply of oxygen with production of soot

   B.inadequate supply of oxygen with production of more heat.

 C. inadequate supply of oxygen with production of soot.

   D.adequate supply of oxygen with production of more heat.

Choose Answer :


(x) Which of the following is the best apparatus for measuring accurately a fixed volume of a given solution?

 A. Measuring cylinder          B. Beaker

   C. Pipette                            D. Burette

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

  1. Group of elements which react quickly with water to form alkaline solution.
  2. The ability of an atom to attract an electron.
  3. Group of elements in which their shells are completely filled up.
  4. A vertical column of elements in the periodic table.
  5. Group element which react slowly with water to form alkaline solution.
  6. Group of elements which react with metals to form salts.
  7. Group of elements which react by receiving electrons.
  8. The systematic arrangement of elements according to their increase in atomic numbers.
  9. Group of elements with high densities and melting points, and often act as catalysts.
  10. Group of elements which have both metallic and non-metallic characteristics.

A. Metalloids

B. Non-metals

C. Periodicity

D. T r a n s i t i o n

elements

E. Electronegativity

F. Alkali metals

G. Halogens

H. Periodic law

I. Alkali earth metals

J. Rare non metals

K. Period

L. Noble gases

M. Periodic table

N. Group

 

 

 

 

View Ans


SECTION C

3.(a) Define the following terms:

(i)Oxidation state

(ii)An element .......„

(iii)A compound

(iv)Fainting

View Ans


(b)Write the chemical formula for each of the following compounds:

(i)Sodium sulphate

(ii)Sodium chloride ..

(iii)Calcium nitrate ......... (iv) Calcium oxide .

View Ans


4.Gas X can be prepared in the laboratory by the decomposition of hydrogen peroxide.

(a)Identify gas X ..

(b)State three physical properties of Gas X

Mention three chemical properties of gas X. (d) State three uses of gas X.

View Ans


5.Write the name of each of the following compounds:

(i)(NH4)2C03

(ii)CaCl2

(iii) NaSO4

(iv) KC103

View Ans


(b)Give three differences between the following:

(i)   Electrovalent compounds and covalent compounds. (ii) Solutions and suspensions.

View Ans


6.State two chemical properties of water.

View Ans


(b) Calculate the molar mass of each of the following compounds:

(ii) NaHC03                        (iii) Fe203

View Ans


(c) State whether each of the following is a chemical or physical change:

(i) Burning of charcoal .........

(i)Rusting of iron sheets

View Ans


7.(a) Study the following Periodic Table and then answer the questions that follow.

(i)Write the collective name of elements in:

 Group Il ..                             Group VIII

(ii)Name the elements which are represented by the following letters:

(iii)Write the electronic configuration of the following elements:

View Ans


(b)Name two products in each of the following fields made by the application of chemistry.

(a)Medicine

(b)Food and be average industry

View Ans


8.(a) Calculate the oxidation number of the underlined elements:

(ii)

(b)What is the use of each of the following apparatus? (i) Thistle funnel    (ii) Pipette .........

 (iii) Wire gauze .........          (iv) Burette .........

View Ans


9.When dilute hydrochloric acid is reacted with zinc metal, gas Z is formed.

(a)Identify the name of gas Z.

(b)Mention four physical properties of gas Z. State two uses of gas Z.

View Ans


10.Define the following terms:

(i)Empirical formula .........

(ii)Molecular formula .........

View Ans


(b)A compound consists of 85.7% carbon and 14.3% hydrogen by mass. If its relative molecular mass is 56, calculate:

(i)Empirical formula.

(ii)Molecular formula.

View Ans


Download Learning
Hub App

For Call,Sms&WhatsApp: 255769929722 / 255754805256

GO TO NECTA EXAMS