1. Choose the correct answer for each from the given options: (17)
1. Which pair of the following molecules has the same number of protons?
O2 and N2
Cl2 and Br2
CH4 and NH3
CO2 and SO2
2. Which one of the following elements is a liquid metal?
3. When does Sulphur burn in oxygen, which one of the following gases is produced?
4. Which of the following gases Is used for respiration?
5. Which of the following changes Is exothermic?
6. What is the pH of a neutral solution?
7. Which one of the following substances contain covalent bonds but also conducts electricity?
8. Which one of the following is not isotoped of hydrogen?
9. The medal given to the third position holder, in any event, is made up of:
10. How many molecules are there in18 gm of water?
G.02 X 1022
6.02 X 1023
6. 20 X 1022
6. 20 X 1023
11. By which process does the smell of the cooked food spread in the surrounding?
12. Which of the following ions has the same number of electrons as an argon atom of atomic number 18?
13. A suspension of droplets of one liquid into another in which it is not soluble is called:
14. In the Periodic Table, the elements have been arranged in the order of increasing:
15. Which one of the following is a compound?
16. Which of the following compounds contains all the three chemical bonds i.e. ionic covalent & coordinate covalent bonds?
17. Which of the following scientist suggested the symbols of the elements?
J .J Berzelius
Chemistry Past Paper 9th Class 2009 Karachi Board
SECTION “B” (SHORT-ANSWER QUESTIONS)(42)
NOTE: Answer 14 questions from this section.
2. Write the names any six branches of Chemistry.
3. Write three significant for studying chemistry. 4. State the following Laws:- (i) law of Conservation of Matter (ii) Law of Constant Composition (iii) Law of Reciprocal
4. State the following Laws:- (i) law of Conservation of Matter (ii) Law of Constant Composition (iii) Law of Reciprocal Proportions
5. Calculate the number of neutrons in the following isotopes:- (i) O (ii) O (iii) O
6. Define Molar Mass and Calculate the molar mass of CaC03. (At. Masses: Ca = 40, C = 12, 0 = 16)
7. Write three uses of potash alum.
8. State the following Laws:- (i) Dobereiner’s law of Triads (ii) Newland’s Law of Octaves (iii) Modern Periodic Law
9. Calculate the amount of silver deposited when a 10-ampere electric current is passed through a solution of AgN03 for 50 minutes. (Electrochemical Equivalent of silver= 0.001118 gm/c.)
10. What is a Thermochemical Reaction? Write the names of its two kinds and define them.
11. Balance the following chemical equations:
(i) NH3 + 02 ———– N02 + H20
(ii) Cu + HN03 ————– Cu (No3)2 + NO + H20
(iii) CuO + NH3 ————– Cu + N, + H20
12. Explain the Kinetic Molecular Theory in different states of matter.
13. Define the following: (i) Saturated solution (ii) Solubility (iii) Crystallization
14. Calculate the pH of 0.01 M HCI solution.
15. Write 3 general characteristics of Transition Elements.
16. State Graham’s Law of Diffusion of gasses. Which gas from among CO2, CH4 and H2 will diffuse the fastest and why? Give the reason.
17. Define the following:- (i) Metallic Bonding (ii) Hydrogen Bonding (iii) Dispersion Forces (London Forces)
18. What are Isotopes? Write the symbols of deuterium and tritium with their atomic numbers and mass numbers. 19. Which elements possess seven electrons in their valence shell? Name the element that has highest
19. Which elements possess seven electrons in their valence shell? Name the element that has the highest electronegativity and gives its value.
20. Define the following:-(i) Alkanes (ii) Alkanes (iii)Alkynee
Define the following: · (i) Metals (ii) Non:metals (iii) Metailiods
21. What is Plastics? Write the names of their two main groups.
Define Double Displacement reaction and give its one example.
22. Define the term “Enthalpy’ of a reaction. Also, write how the change in enthalpy ( Delta.H) is calculated.
Chemistry Past Paper 9th Class 2009 Karachi Board
SECTION ‘C’ (DETAILED-ANSWER QUESTIONS)(26)
NOTE: Attempt 2 questions from this section.
23.(a) Explain, giving balanced chemical equations the Amenia Solvay process for the manufacture of sodium carbonate.
(b) State the Law of Multiple Proportions and explain it with the help of an example.
(c) Write four characteristics of a covalent compound.
24.(a) How is ammonia gas prepared in the laboratory? Explain the process giving a balanced chemical equation and a labeled diagram.
Describe with the help of a labeled diagram the construction and working of a Lead Storage battery.
(b) State the Arrhenius Theory of acids and bases and ex.plain it with the examples of HCl and NaOH.
(c) What is Molarity? Calculate the molarity of an aqueous solution that contains 5.3gm of sodium carbonate dissolved in 500 cm3 solution. (At. Masses : Na = 23, c = 12, 0=16)
25.(a) What is Allotropy? Write the names of any · two crystalline forms of carbon and two characteristics of any one of them.
Describe Rutherford’s experiment which led him to the discovery of the nucleus of an atom.
(b) What is a Coordinate Covalent Bond? How is a coordinate covalent bond formed between NH3 and H+ ion? Explain.
(c) Write four uses of sulphuric acid. OR . State Faraday’s First and Second Laws of electrolysis and write two advantages of electroplating.