TEST DEC2022/CHM421
UNIVERSITI TEKNOLOGI MARA
_________________________________________________________________________
TIME : 1½ HOURS
_________________________________________________________________________
QUESTION 1 (14 MARKS)
a) Formic acid or systematically known as methanoic acid (HCOOH) is the simplest form
of carboxylic acid that has a density of 1.22 g/mL and is 90 % (w/w) HCOOH.
i) Calculate the concentration of methanoic acid solution in molar (M).
(3 marks)
ii) Describe the preparation of 500 mL of 0.70 M acid solution from the above
solution.
(4 marks)
b) A solution is prepared by dissolving 1.5835 g H3PO4 in 250 mL volumetric flask and
diluting it to the calibration mark. Determine the normality of the H3PO4 solution.
(3 marks)
c) Explain how to prepare 100 mL 150 ppm Ca2+ from calcium chloride.
(4 marks)
QUESTION 2 (6 MARKS)
a) Rahim wants to weigh 15.0 g of a hygroscopic compound for an experiment. Identify a
suitable weighing technique for the task and give a reason for your answer.
(2 marks)
b) Ahmad used a beaker to prepare a 250 mL of 1000 ppm standard methylene blue
solution. Has Ahmad’s chosen the appropriate glassware? Justify your answer.
(2 marks)
c) Demonstrate the preparation method to clean stained glasswares using aqua-regia
solution.
(2 marks)
QUESTION 3 (10 MARKS)
a) Define absolute error.
(2 marks)
b) Give two examples of systematic errors in measuring volume of 20 mL solution using
graduated cylinder.
UNIVERSITI TEKNOLOGI MARA
_________________________________________________________________________
TIME : 1½ HOURS
_________________________________________________________________________
QUESTION 1 (14 MARKS)
a) Formic acid or systematically known as methanoic acid (HCOOH) is the simplest form
of carboxylic acid that has a density of 1.22 g/mL and is 90 % (w/w) HCOOH.
i) Calculate the concentration of methanoic acid solution in molar (M).
(3 marks)
ii) Describe the preparation of 500 mL of 0.70 M acid solution from the above
solution.
(4 marks)
b) A solution is prepared by dissolving 1.5835 g H3PO4 in 250 mL volumetric flask and
diluting it to the calibration mark. Determine the normality of the H3PO4 solution.
(3 marks)
c) Explain how to prepare 100 mL 150 ppm Ca2+ from calcium chloride.
(4 marks)
QUESTION 2 (6 MARKS)
a) Rahim wants to weigh 15.0 g of a hygroscopic compound for an experiment. Identify a
suitable weighing technique for the task and give a reason for your answer.
(2 marks)
b) Ahmad used a beaker to prepare a 250 mL of 1000 ppm standard methylene blue
solution. Has Ahmad’s chosen the appropriate glassware? Justify your answer.
(2 marks)
c) Demonstrate the preparation method to clean stained glasswares using aqua-regia
solution.
(2 marks)
QUESTION 3 (10 MARKS)
a) Define absolute error.
(2 marks)
b) Give two examples of systematic errors in measuring volume of 20 mL solution using
graduated cylinder.
