Exam Questions Second Term SS 1 Chemistry

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CHEMISTRY SS1 2ND TERM QUESTION.

SECTION A

1. What is the relative atomic mass of potassium A. 40 B. 39 C. 32 D. 24

2. An element with relative atomic mass 108 is A. Ca B. Cl C. Ag D. Al

3. Modern standard element with which chemist define relative atomic mass is A.12C B.C13 C.3H D.16O

4. A molecule of neon is A. diatomic B. monoatomic C.triatomic D. polyatomic

5. H2SO4 + xKOH → K2SO4 + yH2O. The value for x and y in the above equation is A. 1 and 2 B. 2 and 3 C. 2 and 1 D. 4 and2

6. The balanced chemical equation for the reaction between hydrochloric acid and sodium hydroxide is A. NaOH + HCl → NaCl + H2O B. NaCl + HCl → NaOH + H2O

C. NaOH + H2SO4 →Na2SO4 + H2O D. H2SO4 + KOH → K2SO4 + H2O

7. The mole ratio in which reactants combine and products are formed is known as A. rate of reaction

B. stoichiometry of reaction C. equation of reaction D. chemical reaction

8. The unit for relative molecular mass is A. mole B. gmol-1C. grams D. mass

9. What mass of Pb(NO3) would be required to 9g of PbCl2 on the addition of excess NaCl solution? [Pb=207, Na=23, O=16, N=14] A. 10.7g B. 1.2g C. 6.4g D. 5.2g

10. What is the molar mass of Na2SO4? A. 172 B.168 C.142 D.133

11. The empirical formula of a compound is CH, the molecular formula could be A. C2H4

B.CH4C. C7H12D. C6H6

12. An oxide of nitrogen contains 69.6% of oxygen by mass. Its empirical formula is A. N2O3 B. N2O2C. N2O D. NO2

13. All pure samples of chemical compound contain the same element in the same proportion by mass is a the law of—— A. definite proportion B. reciprocal proportion C. multiple proportion

D. conservation of matter

14. What is used to measure the mass of atom and molecules? A. Beam balance B. Spring balance

C. Chemical balance D. Mass spectrometer

15. What is the ratio by mass of oxygen and hydrogen in 1 mole of water?A. 3:1 B. 2:1 C.1:2 D. 2:4

16. In electrovalency, valence electrons are transferred and the atomic number is A. reduced B. stabilized C. unaffected D. increased

17. An element Y having an atomic number of 19 combines with another element Z with atomic number 17. The likely compound formed is A. Y2Z B. Y3Z2C. YZ D. Y2Z2

18. The type of attractive force which exist between discrete molecules is calledA. metallic bond

B. hydrogen bondC. dative bondD.van der Waals’ forces

19. Presence of sodium chloride in ice will A. decrease the melting point of the ice B. increase the melting point of the ice C. make sodium chloride impure D. lower the freezing point of sodium chloride

20. Which of these does not support the kinetic theory? A. Brownian motion B. Diffusion C.Osmosis

D. Linear expansivity

21. The phenomenon whereby the atmospheric pressure equals the saturated vapour pressure is called

A. freezing B. latent heat C. boiling D. normal pressure

22. From the ideal gas equation, PV = nRT, the unit of n is A. atmdm3B. atmdm3/K C. mole D. K/mole

23. What will be the new volume (V) if the new pressure is halved and the initial pressure remain the same the sameA. 2P1V1 = P2V2B. P1V1 = 2P2V2C. P1V1/2= P2V2/2 D. P1V1 = P2V2/2

24. A fixed mass of gas of volume 546cm3 at 0oC is heated at constant pressure. What is the volume of the gas at 2oC? A. 550cm3B. 560cm3C. 570cm3D. 580cm3

25. Calculate the minimum volume of oxygen required for the complete combustion of a mixture of 20cm3 CO and 20cm3 of H2. A. 10cm3B. 20cm3C. 40cm3D. 60cm3

SECTION B

1. The vapour densities of O2 and Cl2 are 16 and 36 respectively. If 60cm3 of O2 diffuses through a porous partition in 14 seconds, how long will it take 1000cm3 of Cl2 to diffuse through the same partition?

2. A given mass of nitrogen is 0.12dm3 at 60oC and 1.01 x 105Nm-2. Find its pressure at the same temperature if its volume is changed to 0.24dm3

3. A bottle of milk is taken out of the refrigerator and placed on the table. Droplets of water are noticed on the surface of the milk bottle. Explain the observation

4. A. Illustrate the formation of the compound AlCl3 using electron dot representation

B. State two properties of the compound

5. Define hydrogen bond

i. 8.50g of CuO when heated in a current of dry hydrogen gas gave 6.58g of copper and 2.16g of water. Calculate the proportion of oxygen to hydrogen by mass in water.

6. Balance the following equations:

i. C4H10 + O2 → CO2 + H2O

ii. H2SO4 + NaOH → Na2SO4 + H2O

7. Calculate the % by mass of water of crystallization in Al2(SO4)3.9H2O

8. Calculate the volume of nitrogen that will be producedat s.t.p from the decomposition of 9.60g ammonium dioxonitrate(iii), NH4NO2.

9. Balance the following equation: H2SO4 + Na2CO3 → Na2SO4 + H2O + CO2

Ca(OH)2 + CO2 → CaCO3 + H2O

10. How many moles are there in 10g of iron (II) tetraoxosulphate (VI)?