TUTORIAL: CHAPTER 1

1. 1. Identify the type of analysis (quantitative, qualitative, or both) required for the following

problems:

(a) A forensic laboratory needs to investigate a suspicious white powder found at

a crime scene to determine its identity and the level of potential threat.

• Qualitative

• Quantitative

• Both

(b) A local coffee shop has to determine the type of coffee suitable for a new drink

recipe.

• Qualitative

• Quantitative

• Both

(c) The laboratory unit is tasked with determining the concentration of heavy

metals, specifically lead (Pb), in UiTM Tapah’s pond.

• Qualitative

• Quantitative

• Both

(d) A student adds a few drops of colourless solution Y to a test tube containing

yellow bromine water to observe any colour change.

• Qualitative

• Quantitative

• Both

(e) An analyst performed an acid-base titration to determine the percent content of

acetic acid in vinegar.

• Qualitative

• Quantitative

• Both

(f) A researcher measures the tensile strength of different nanomaterials to develop

more durable and lightweight products.

• Qualitative

• Quantitative

• Both

2. 2. State any four (4) required steps in chemical analysis.

Answer explanation

i) Defining problem

ii) Selecting the method

iii) Obtaining a representative sample

iv) Prepare the sample for analysis

v) Performing any necessary chemical separations

vi) Performing/conducting the measurements / experiments

vii) Gathering the results & reporting the data

(1/2 mark x any 4 = 2 marks)

3. 3. State three (3) factors that need to be considered in selecting a method for quantitative

analysis.

Answer explanation

i) Sample type

ii) Size of sample

iii) Level of accuracy

iv) Sample preparation needed

v) Transportation/storage of sample

(1 mark x any 3 = 3 marks)

4. 4. A true value of titration volume in an analysis is reported to be 25.20 mL. Identify

   whether the following data is accurate or precise or both or neither.

(a) Fatima obtained three readings of 23.20 mL, 23.10 mL and 23.00 mL.

• Precise

• Accurate

• Accurate and precise (both)

• Not accurate not precise

(b) Salleh obtained three readings of 25.20 mL, 25.10 mL and 25.20 mL.

• Precise

• Accurate

• Accurate and precise (both)

• Not accurate not precise (neither)