1) a) Distinguish between the terms qualitative analysis and quantitative analysis.
b) Describe one example of each type of analysis. 2) A student was supplied with a stoppered bottle containing a mixture of kerosene and water. a) The mixture had separated into two layers. Explain why this separation occurred. b) Identify the liquid present in the lower layer. c) Outline the steps to gravimetrically determine the percentage by weight of kerosene in the mixture. 3) A 15.0 g sample of sterling silver contained 13.95 g of silver. the remainder was copper. Calculate the percentage by weight of each metal in the sterling silver. 4) Pewter utensils are composed of 85% tin, 8% copper and 7% bismuth by weight. Calculate the mass of each metal in a pewter drinking goblet with a mass of 250g. 5) Students were asked to analyse a mixture of sand and salt water to determine its percentage composition of each component by weight. a) Each team designed a method to perform the task. One suggested that they should first determine the total mass of the sand and salt water mixture. Explain how the students performed this task. b) The next step was to choose an appropriate method to seperate the sand from the salt water. Identify the best physical separation technique to use. c) Explain how the salt can be separated from the salt water. d) One group's results are shown below. Calculate the % composition of the mixture. Total mass of sand + salt water + beaker = 185.79 g Mass of beaker = 143.61 g Mass of sand (dried) = 24.88 g Mass of salt (dried) = 1.25 g e) Discuss the likely sources of error in this experiment. Click here for the solutions to this quiz!
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