- You are provided with.
- Solid A
- 2M hydrochloric acid solution B
- 1M sodium hydroxide solution D
You are required to determine the enthalpy change for the reaction between solid A and one mole of hydrochloric acid.
PROCEDURE A
Using a burette, place 20 cm3 of 2M Hydrochloric acid, solution B in 100ml beaker. Measure the temperature of the solution after every one minute and record the values in the table. At exactly 2 ½ minutes add all solid A to the acid. Stir the mixture gently with the thermometer. Measure the temperature of the mixture after every half a minute and record the values in the table. RETAIN THE MIXTURE TO BE USED IN PROCEDURE 2
TABLE 1(5mks)
Time( min)
0
½
1
1 1/2
2
2 1/2
3
3 1/2
4
4 1/2
5
Temperature (o c)
X
- Plot the graph of temperature against time (3mks)
- Using the graph determine the temperature change (1mk)
- Calculate the heat change for the reaction. (Assume the specific heat capacity of the mixture is 4.2j/kg/k and density of the mixture is 1g/cm3.) (1mk)
PROCEDURE B
Rinse the burette thoroughly and fill it with sodium hydroxide (D).Transfer all the contents of 100ml beaker used in procedure A into 250ml volumetric flask. Add distilled water up to the mark. Label the solution C. using pipette and pipette filler place 25cm3 of solution C into 250ml conical flask. Add 2 to 3 drops of phenolphthalein indicator and titrate against sodium hydroxide. Record the results in the table 2. Repeat titration two more times and complete the table 2 (4mks)
TITRATIONS
1
2
3
Final burette reading (cm3)
Initial burette reading (cm3)
Volume of solution C used (cm3)
- Calculate the average volume used (1mk)
- Calculate the number of moles of sodium hydroxide used (1mk)
- Calculate the number of moles of hydrochloric acid in 25cm3 of solution C (1mk
- Calculate the number of mole of hydrochloric acid in 250cm3 of solution C (1mk)
- Calculate the number of moles of hydrochloric acid in 20cm3 of solution B (1mk)
- Calculate the number of moles of hydrochloric acid that reacted with solid A (1mk)
-
- You are provided with solid E which is suspected to be zinc carbonate. Using reagents below describe how you can confirm its presence
- Solid E
- Dilute nitric (v) acid
- Aqueous sodium hydroxide
- Aqueous ammonia solution
- Wooden splint
-
Carry out the actual tests described above.
Test 1
Test 1
Expected observations
(1mk)
(1mk)Test 2
Test 1
Expected observations
(1mk)
(1mk)Test 3
(1mk)Test 1
Expected observations
(1mk)
(1mk)
- You are provided with solid E which is suspected to be zinc carbonate. Using reagents below describe how you can confirm its presence
- You are provided with solid F. Carry out the tests below and record your observations and inferences in the spaces provided.
- Put half spatula full of solid F and burn on non-luminous flame of the Bunsen burner.
Test 1
Expected observations
(1mk)
(1mk)
- To the remaining portion of solid F, add about 10cm3 of distilled water in a boiling tube and divide into two portions
Test 1
Expected observations
(1mk)
(1mk)
- To the first portion add acidified potassium manganate (VII) and shake
Test 1
Expected observations
(1mk)
(1mk)
- To the second portion add all the solid sodium hydrogen carbonate provided.
Test 1
Expected observations
(1mk)
(1mk)
- Put half spatula full of solid F and burn on non-luminous flame of the Bunsen burner.
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