Download SS1 CHEMISTRY 3RD EXAM past questions and answers

	     	   
                    	 	   THIRD TERM  EXAMINATION, 2010/2011 SESSION.
                      	   SUBJECT: CHEMISTRY 2    			 
             CLASS: SSS 1	       	         	    TIME ALLOWED: 2½HRS 
 

   INSTRUCTION: Answer ALL the questions. 
1.	Two miscible liquids with boiling points of 750c and 850c respectively can be separated by    a. crystallization	
	b. evaporation	c. fractional distillation   d. simple distillation
2.	The fundamental particles of an atom are 
	a. neutron, proton and ion 	b. proton and neutron      
	c. proton, electron and molecule      d. proton, electron and neutron 
3.	The formula of a compound formed between the atoms of elements Q and R with atomic numbers 13 and 8 respectively is
	a. Q2 R3	b. R2 Q3	c. Q3 R2	d. R3 Q2
4.	In a titration experiment, the base is put into the 
	a. conical flask	b. burette	 c. measuring cylinder     d. pipette
5.	Acids exhibits the following properties excepts that they 
	a. have a sour taste	b. change the colour of indicators
	c. are soapy to touch	  d. react with some metals and liberate hydrogen
6.	At 200c, oxygen has a volume of 500cm3 under a pressure of 700mmHg. What would be its volume in cm3 at the same temperature if the pressure is reduced to 505mmHg?
	a. 693.1	b. 693.0	c. 69.31	d. 6.931
7.	The process whereby large hydrogen molecules are heated at high temperatures in the presence of a catalyst to give smaller molecules is known as 	a. degradation	b. disintegration	   c. cracking  	d. polymerization 
8.	What is the oxidation state of chromium in the compound Na2Cr2O7?
	a. +2		b. +3		c. +5		d. +6
9.	Which of the following ions has the electron configuration 2, 8, 8
	a. Na+	b. Mg2+	c. F-		d. Cl-
10.	An element with the electron configuration of 1s2 2S2 2p6 would have a combining power of 	a. 0	 b. 2	  c. 6	    d. 8
11.	The bond formed for when two electrons are that are shared between two atoms are donated by only one of the atoms is
	a. covalent		b. dative	 c. ionic	d. metallic


12.	The number of atoms in one mole of a substance is equal to the
	a. mass number	 	b. oxidation		c. atomic number    d. Avogadro number
13.	Which of the following statements about molar solution is correct? It
a. is a supersaturated solution	b. cannot dissolve more of the solute at that temperature	c. contains any amount of solute in a given volume of solution  d. contains one mole of the solute in 1dm3 of solution
14.	A gas that is collected by upward delivery is likely to be	
	a. heavier than air	b. insoluble in water	c. lighter than air
	d. soluble in water
15.	The equation P = k/v illustrates	a. Charles’ law	b. Dalton’s law
	c. Boyle’s law	d. Gay Lussac’s law
16.	The volume occupied by 17g of H2S at S.T.P is? [H = 1, S = 32, Molar volume = 22.4dm3]	a. 11.2dm3	     b. 17.0dm3	c. 34.0dm3   d. 44.8dm3
17.	The initial volume of a gas at 300k was 220cm3. Determine its temperature if the volume became 250cm3
	a. 183k	b. 264k	c. 300k	d. 341k
18.	The colour of phenolphthalein indicator in alkaline solution at the end-point of an acid base titration is 	a. yellow    b. orange    c. pink	d. colourless
19.	Water from a river contaminated by alkali waste will have a PH of about
	a. 9	 b. 7	  c. 5	   d. 3
20.	2NaNO3(aq)  ?  2NaNO2(aq)  +  O2(s). From the above equation, what is the volume of oxygen produced at S.T.P when 8.5g of NaNo3 is heated until no further gas is evolved. [NaNo3 = 85, Molar volume of gases at s.t.p = 22.4dm3]	a. 1.12dm3	     b. 2.24dm3	 c. 4.48dm3    d. 11.2dm3
21.	An isotope has an atomic number of 15 and a mass number of 31. The number of protons it contains is     a. 46      b. 15      c. 31     d. 16
22.	Which of the following is a deliquescent compound?
	a. CaCl2	b. Cuo	c. Na2Co3. 10H2O	d. Na2Co3
23.	The constituent of baking powder that makes dough to rise is 
	a. NaoH	b. NaNo3	     c. NaNHCO3		d. Nacl
24.	People often hang their clothes out to dry. This is an example of the process of 	          a. Sublimation	b. Condensation 	c. Evaporation	d. Precipitation



25.	When element 20A combines with element 8Y, 	
	a. A covalent compound AY is formed	  b. An ionic compound, AY is formed 	c. An ionic compound A2Y is formed	d. A covalent compound, AY2, is formed
26.	An element X exhibits isotopy; this means that the isotopes of X have
	a. the same number of neutrons	b. different number of neutrons	
	c. different number of protons	d. different number of electrons
27.	Exposure to a large quantity of carbon(ii) oxide is dangerous to health because	a. it is a reducing agent	b. it is an oxidizing agent
	c. when inhaled it prevent hemoglobin in the blood from carrying oxygen
	d. it burns the skin and the eyes
28.	Which of the following can best be used for drying ammonia?
	a. Concentrated H2SO4		b. fused Calcium chloride     c. Calcium oxide
	d. water
29.	Diamond is very hard and unreactive because
	a. It is ionic	b. each carbon atom is covalently bonded to four other carbon atoms	 c. It has strong hydrogen bond between the carbon atom	d. it has a high melting point
30.	Which of the following compounds is an acid salt
	a. NaHSO4		b. Na2SO-4		c. Nacl	d. Na2S
31.	Tetraoxophosphate(v) acid has a basicity of 	a. 7      b. 5    c. 4    d. 3
32.	Which of the following acids can form both acid salt and normal salt
	a. Conc HNO3	b. dil Hcl	c. dil H2SO4	d. Conc CH3CooH
33.	The empirical formula of a hydrocarbon containing 0.12mole of carbon and 0.36 mole of hydrogen is? [H = 1,	C = 12]
	a. CH2	b. CH3	c. C2H2	d. C2H4
34.	When an element exist in two or more forms in the same physical state, the element is said to exhibit		a. Isotopy	     b. Isomerism   c. Allotropy	d. Hygroscope
35.	A salt, which loses mass when exposed to air is 
	a. hygroscopic	b. deliquescent	    c. efflorescent	   d. effervescent 
36.	Water gas is mixture of 	a. CO2 and H2	 b. CO and H2O
	c. CO and N2	d. CO and H2
37.	What is the percentage by mass of copper in copper (i) oxide (Cu2O)?
	[Cu = 64, H = 1,	O = 16]    a. 88.9%     b. 80.0%     c. 66.7%   d. 20.0%


38.	Which of the following is not a direct petroleum product?
	a. Ethane	   b. Petrol	   c. Vaseline	d. Kerosene 
39.	Which of the following properties is not characteristic of electrovalent compound?	a. high vapour pressure	b. solubility in polar solvent	c. high melting and boiling point	          d. formation of crystalline solids
40.	The following compounds contain the same type of bonds except
	a. sodium chloride	b. hydrogen chloride	 c. magnesium chloride
	d. potassium chloride
41.	Destructive distillation of coal means?	a. heating coal in plentiful supply of air	          b. burning coal in air to produce water and CO2
	c. heating coal in the absence of air	d. heating coal in limited supply of air
42.	In chemical reaction, the reacting species posses energy of motion known as 	          a. Potential energy     b. free energy    c. bond energy
	d. kinetic energy
43.	Which of the following contain the highest number of electrons in the outermost shell	a. 8O	     b. 10Ne	     c. 15P	d. 19K
44.	The oxidation number of phosphorus in PO43- is 
	a. +5		b. +4		c. +3		d. -3
45.	Petrol can be obtained from diesel by 
	a. distillation	b. cracking	        c. reforming		d. catalysis
46.	Which of the following formula is incorrect?
	a. Ca(OH)2		b. Mg(NO3) 2		c. Al(SO4)3      d. Fe2O3
47.	Which of these gases is used as a refrigerator coolant
	a. CO	b. Cl2		c. CO2	d. H2S
48.	xKClO3(s)  ?  yKCl(c) + zO2(g). The value of x, y and z in the above equation is		a. 3, 2, 2	b. 2, 2, 3	c. 2, 3, 2	d. 3, 2, 3
49.	400cm3 of gas X diffused through a porous pot in 2 minutes. Calculate the rate at which X diffuses 		a. 6.3cm33s-1	b. 20cm3s-      c. 200cm3s-		d. 3.33cm3s-
50.	The fraction of crude oil used as jet fuel is 
	a. Refined gas	b. Diesel oil	c. Kerosene	d. Gasoline 






SECTION B – THEORY
Answer any 4 questions
a. what is a salt                                                                                       1½mks
mention two types of salt with specific examples                               3mks
list the criteria for preparing salt                                                         2mks
4.10g of hydrated magnesium tetraoxosulphate vi crystal gave 2.00g of anhydrous salt on heating. Calculate the formula of the hydrated salt (Mg = 24, S= 32 O= 16)  3mks
Describe the following characteristics of some salts i. Efflorescent ii. Deliquescent iii. hygroscopic                                                                                              3mks                                                                  

a. what is PH                                                                                                   1½mks
      b. what is the PH of 0.01M of H2SO4                                                                                             2mks                                                
c. differentiate between isotope and allotrope with example                           3mks
d. give 3 differences diamond and graphite                                                     3mks
e. state one importance each of the following amorphous of carbon               3mks
i. wood charcoal ii animal charcoal iii soot                                                          

a. explain briefly why graphite is a good conductor of heat and electricity and diamond is not  1½mks
b. list 4 types of coal                                                                                                        4mks
c. give one product of destructive distillation of coal that is i. solid  ii. Liquid  iii. Gas      3mks
d. i. differentiate between heavy chemicals and fine chemicals                                       2mks                      
    ii. Give two examples each                                                                                         2mks







a. with the aid of diagram and suitable equation, describe the laboratory preparation of carbon iv oxide                                                                                                                     5mks                     
b. give 2 chemical properties of carbon iv oxide                                                  2mks
c. give 2 uses of carbon iv oxide                                                                          2mks
d. how would you test for carbon iv oxide                                                           2mks
e. why is carbon ii oxide dangerous to life                                                           1½ mks

a. calculate the volume of CO2 at s.t.p that would be produced from 80.0g of Fe2O3 according to the following equation                                                                                   4mks
b. Fe2O3(s)  +  3CO2(g)                 2Fe(s)  +  3CO2(g)  (Fe= 56, O=16 M.V of gas at s.t.p =22.4dm3)
c. balance the following equation
i. SO2  + O2            SO3
ii. Fe  +  H2O              Fe3O4  +  H2
iii.  KOH +H2SO4        K2SO4  + H2O                                                                   3mks
d. describe the procedure for separating the mixture of soluble salt and sand    2mks
e. define the following i. cracking  ii. Octane number                            2mks
f. give any 3 fractions of crude oil                                                           1½mks