Part 1: Crackers contain two types of carbohydrate: starch and reducing sugars (such as glucose).
Describe the chemical tests that could be used to show the presence of these two types of carbohydrate in a cracker sample.
Include a risk assessment in your answer.
Part 2: A student investigated three brands of crackers.
For each brand of cracker, the student:
Their results are shown below:
| Brand of cracker | Time taken for cracker to taste sweet (seconds) |
|---|---|
| Brand A | 28 |
| Brand B | 42 |
| Brand C | 19 |
Answer the following questions based on this study:
What was the dependent variable in this investigation?
Give one control variable that the student used, or should have used, in this investigation.
Explain why the crackers began to taste sweet during the investigation.
Suggest one reason why the results of this investigation might not be valid. Do not refer to control variables in your answer.