1 Classify the following analyses as qualitative or quantitative. a an analysis that showed that Vegemite contains 0.55 mg of vitamin B1 and 0.80 mg of riboflavin per 5 g b detection of toxic materials in the gaseous discharge from a factory c confirmation of the presence of lead in a sample of blood
d comparison of the concentrations of trace elements in glass fragments removed from the skin of a hit-and-run accident victim with those in the glass fragments from the broken headlights of a suspect’s car. 2 Look at Table 1.1. List the techniques from the table that are based on the: a physical properties of the substance being tested
b chemical properties of the substance being tested.
Quantitative and qualitative analysis
3 Think back to when you fi rst got up this morning. List every product you were in contact with during the fi rst 30 minutes you were awake. a How many of these products are made from materials that have been processed? b How many are unprocessed?
c Is there any evidence that any products you have listed were subject to some process of quality control? 4 The ingredients of a bottle of jam are listed on the label as ‘sugar, strawberries, pectin and food acid (citric acid)’. a Is this an example of qualitative or quantitative analysis? b Rewrite this label so that it is an example of analysis of the other type. 5 Which of the following represents example(s) of quantitative analysis? I A sample of ‘fries seasoning’ contains salt, chicken extract, rice flour, paprika and chilli. II Dry air contains 78% nitrogen vol/vol.
III A sample of iron ore weighs 23.5 kg.
IV A chocolate biscuit contains 2.3 g protein, 6.6 g fat and 24.4 g carbohydrate per 100 g serve.
A IV only
B I and IV
C II and IV
D II, III and IV
6 Analytical chemists use a variety of techniques. Give an example of the information provided by each of the following techniques. a gravimetric analysis
b volumetric analysis
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