Use of Techniques, Apparatus and Materials
77 questions· page 1 of 8
Complete Table 3.1.
Table 3.1
| reagent used | colour of reagent at the start | final colour of reagent | conclusion |
|---|---|---|---|
| Benedict's solution | blue | trace of reducing sugar present | |
| biuret | blue | protein present | |
| iodine solution | black |
The composition of inhaled air differs from that of exhaled air.
Complete Table 3.1 for water vapour in exhaled air and state the test for the presence of each of the three gases.
Table 3.1
| inhaled air | exhaled air | test | |
|---|---|---|---|
| carbon dioxide | 0.04% | 4.0% | |
| oxygen | 21% | 16.0% | |
| water vapour | variable – depends on environment |
Glucose is a reducing sugar.
Describe how you would test for glucose safely in your laboratory.
Describe how you would use Benedict's solution to test for reducing sugar in a piece of potato. Include details of a safety precaution in your answer.
You are given a 1.0% glucose solution. Describe in detail how you would use it to produce of a 0.5% glucose solution.
After the students had tested the glucose solutions in Table 1.1 with Benedict's solution, they noticed that a solid (precipitate) had collected at the bottom of the test-tubes.
They decided that finding the mass of the solid was another way of measuring the concentration of glucose in the solution.
Suggest how the students could separate this solid from the solution and obtain its mass.
Suggest a suitable reagent for the test for starch and describe how it should be used.
Details of possible results are not required.
______
Describe how you would keep the test-tubes at the required temperature for ten minutes.
______
Describe how you would test the apple for protein, and state what you would observe if protein was present and not present.
test ______
protein present ______
protein not present ______
Milk contains a reducing sugar. Explain how you could safely compare the reducing sugar contents of samples of cow's milk and goat's milk.
Suggest a method that he could use to determine this volume of milk.
Some of the outer cells in the photomicrograph contain small particles.
Describe in detail how you would prepare a section of the root for observation under the microscope to see whether these cells contain starch.