NAME………………………………………………………	INDEX NO………………………. …………...…
SCHOOL……………………………………………...…….	CANDIDATE’S SIGNATURE………………….
DATE………………………………………..

233/3
CHEMISTRY 
PAPER 3
(PRACTICAL)
MARCH/APRIL 2015 
TIME: 2 ¼ HOURS 

KABONDO DIVISION JOINT EVALUATION TEST 
Kenya Certificate of Secondary Education (K. C.S.E.) 

CHEMISTRY 
PAPER 3
(PRACTICAL)

INSTRUCTIONS TO CANDIDATES 
• 	Write your name and Index number in the spaces provided above.
•	Sign and write the date of examination in the spaces provided.
• 	Answer all the questions in the spaces provided 
• 	You are not allowed to start working with the apparatus for the first 15minutes of the 2 ¼ hours allowed for this paper. This time is to enable you to read the question paper and make sure you have all the chemicals and apparatus that you may need
•	All working must be clearly shown where necessary.
•	Mathematical tables and silent non-programmable electronic calculators may be used.

FOR EXAMINERS USE ONLY

Question	Maximum Score	Candidate’s Score	
1 	16		
2	12		
3	12		
TOTAL SCORE	40		

This paper consists of 8 printed pages .Candidates should check the questions  to ensure that All the pages are printed as indicated and no  questions are missing.

1.	You are provided with: 
	• 1 .5g of metal Carbonate A 
• 75cm3 of 1M hydrochloric acid labelled B 
• 75cm3 of 0.1M sodium hydroxide labelled C 
You are required to determine the molar mass of the carbonate 

Procedure I 
Transfer carefully all solid A into a clean 250m1 volumetric flask. Add 50cm3 of the acid labelled B into the flask containing the carbonate. Wait until the reaction is complete (No more effervescence takes place) 

Procedure II 
When the reaction is complete, add 100cm3 of distilled water to the contents of the flask and shake. Add more distilled water to top the solution to the mark. Label it as solution D. Pipette 25cm3 of solution D into a 250cm3 of conical flask and titrate with solution C using 1 to 2drops of phenolphthalein indicator. Record your results in table 1 below. Repeat this procedure to obtain accurate values: 
	I 	II 	III 	
Final burette reading (cm3) 				
Initial burette reading (cm3) 				
Volume of solution C used (cm3) 				

Questions 
(a) Find the moles of hydrochloric acid present in 50cm3 of solution B			 (lmk)

(b) 	Determine the average volume of solution C used 					(lmk )

(c) 	(i) 	Calculate the volume of sodium hydroxide that would react with 250cm3 of the 
diluted acid									 (2mks) 

 (ii) 	Calculate the moles of sodium hydroxide solution C in the volume obtained in c(i) 
above.										(1mk)

(d) 	Write down equation for the reaction between hydrochloric acid and sodium hydroxide 
(1mk)

(e) 	How many moles of hydrochloric acid are left after the reaction with the metal carbonate 
A 											(1mk)

(f) 	Calculate the moles of hydrochloric acid that reacted with l.5g of the metal Carbonate A 
											(1mk)

(g) 	(i) Write down the ionic equation between carbonate and hydrochloric acid 	(1mk) 

(ii) 	Calculate moles of carbonate A 						(1mk) 

(iii) 	Calculate the molar mass of the carbonate A 					(1mk)

2. 	You are provided with: 
- 2.0M sulphuric (VI) acid solution, solution Z 
- 0.42M glucose, solution X 
0.04M potassium manganate (VII) solution Y 
You are required to determine the rate of reaction between aqueous glucose solution and acidified potassium manganate (VII) at different temperatures. 

Procedure 
Place 1cm3 of solution Y into a conical flask. Using a 100cm3 measuring cylinder add 25cm3 of solution Z to the conical flask containing solution Y. Warm the mixture to about 70°C. Stop warming and allow the mixture to cool. When the temperature is exactly 65°C add 7.5cm3 of solution X and start the stop watch immediately. Stir the mixture with a thermometer and measure the time taken for the colour of the mixture to change from purple to colourless. Record the time in table 2 below also record the temperature at which the mixture turn colourless. Clean the conical flask and repeat the procedure at temperature of 60°C, 55°C 50°C and 45°C instead of 65°C. 
(a) 	Calculate 1/time and complete the table 
table 2 										(6mks) 
Temperature before mixing (°C) 	65 	60 	55 	50 	45 	
Temperature when solution becomes colourless (°C) 						
Time in seconds 						
1/time(S-1)						

(b) 	Plot a graph of 1/time (y-axis) against the temperature at the point when the solution becomes colourless 									(3mks)

(c) 	From your graph, determine the time that the reaction would take if the temperature at 
  	which the solution becomes colourless is 52.5°C 					(1mk)

(d) 	From your graph, determine the rate of reaction if the temperature at which the solution becomes colourless is 47°C 								(1mk)

(e) 	Explain the shape of your graph 							(1mk)

3. 	You are provided with mixture K. You are required to perform tests on the mixture in order to determine its composition. Record your observations and inferences in their spaces provided: 
(a)	Place a spatula of K on a white tile and observe its appearance: Observation 
          Observations	                      Inferences	

                                                        
( ½ mk)	 

                                           ( ½ mk)	

(b) 	Place the remaining portion of K in a boiling tube and add 10cm3 of distilled water. Shake vigorously, filter and retain both the residue and filtrate 
          Observations	                      Inferences	

                                                           
( 1mk)	 

                                           ( ½ mk)	

i)	Divide the filtrate into 3 portions. To the first portion sodium hydroxide drop-wise until excess 
          Observations	                      Inferences	

                                                          
( ½ mk)	 

                                           (1mk)	

(ii) 	Dip one end of a metallic spatula in 2M HC1 and heat it in a Bunsen burner flame for a few seconds and allow it to cool. Scoop a little of the solution from the second portion with the heated end of the spatula and place it as the hottest part of the non-luminous flame. 
          Observations	                      Inferences	

                                                            
( ½ mk)	 

                                           ( ½ mk)	

(iii) To the third portion add 3-4 drops of dilute HNO3 (aq) followed by 3-4 drops of BaCl2 (aq) 
          Observations	                      Inferences	

                                                            
( ½ mk)	 

                                           ( ½ mk)	

 (c) 	Scrap the residue from the filter paper and place a half of it in a clean dry test tube. Add 
about 3cm3 of 2M HNO3. Test for any gas produced by use of calcium hydroxide solution on a glass rod. Preserve the solution for use in procedure (d) below: Observation 
          Observations	                      Inferences	

                                                            
( ½ mk)	 

                                           ( ½ mk)	

(d) 	Add about 3cm3 of distilled water to the solution obtained in (c) above and shake to mix. 
Divide the solution into 3 portions 
(i) 	To the first portion, add sodium hydroxide drop-wise until in excess 

          Observations	                      Inferences	

                                                      ( 1mk)	 

                                           ( 1mk)	

(ii)	To the second portion, add ammonia solution drop-wise until in excess 

          Observations	                      Inferences	

                                                            

( ½ mk)	 

                                           ( ½ mk)	

(iii) 	To the third portion, add 2-3drops of potassium iodide solution 
          Observations	                      Inferences	

                                                            

( ½ mk)	 

                                           ( ½ mk)