2013/2014 REAL WAEC CHEMISTRY PRATICAL

2013/2014 REAL WAEC CHEMISTRY
SPECIMEM i. Red and Blue Litmus Paper
ii. Aqueous NH3
iii. Dilute HCl
iv. Barium Chloride Solution
vi. Dilute HNO3
vii. AgNO3
vii. Lime Water

APPARATUS. *Glass rod*Filtration paper *Spatula *Two boiling tubes *Four test tubes *Methyl Orange Indicator *Wash Bottle containing distilled water [H2O] [-]2.8cm3 of concentrated H2SO4---An [-]3?9g of NaOH per dm3 of solution---Bn [-]6.6g of (NH4)2SO4 per dm3--- Cn [-]FeCl3 per dm3

CHEMISTRY PRACTICAL :: WHAT TO EXPECT. QUESTION 1 is always on TITRATION. Guess by now you should know how to TABULATE your readings & AT THE SAME TIME,

MANIPULATE YOUR READINGS TO GET YOUR END POINT. [N.B :: Your teacher will give you an end point you will work on.]

PRACTICE HOW TO MANIPULATE YOUR TABLE. Remember, this is key. IF YOUR SCHOOL'S END POINT is 23.30cm^3, YOU SHOULDN'T EXCEED or - 0.20. i.e IT'S A THING OF PLUS OR MINUS 0.20.

IF YOUR SCHOOL'S END POINT IS 23.30, IT'S EITHER YOUR ANSWER IS 21.30, 24.30 or 25.30, 22.30. | AND PLEASE NOTE Your Volume of Pipette Used Should be noted on your answer sheet. Indicator Used should also be noted. To show how good you are, you can also decide to tell the examiner the SOLUTION IN BURETTE & also SOLUTION IN PIPETTE.(BEFORE THE TABLE) | DON'T FORGET TO PUT THE UNITS OF ALL WHAT YOUR HAVE CALCULATED. ANY UNIT OMITTED ATTRACTS A DEDUCTION OF 1/2 (Half mark) | SO BE CAREFUL. MAKE REFERENCE TO YOUR PAST QUESTION BOOKLET FOR MORE. THAT'S ALL ON TITRATION.

TEST :: Cn Heat
OBSERVATION :: Gas evolved.
INFERENCE :: NH3 form NH4 salt present.

TEST :: Cn HCl BaCl
OBSERVATION :: White precipitate formed. *Insoluble in excess dilute HCl
INFERENCE :: SO4^2-, SO3^2-, CO3^2- suspected. *SO4^2- present.

TEST :: Dn NaOH
OBSERVATION :: Reddish Brown Precipitate formed. Insoluble in excess.
INFERENCE :: Fe3 present.

TEST :: Dn aqueous NH3
OBSERVATION :: Reddish Brown