[B] Food Tests

Question 1

What is the purpose of food tests in the AQA GCSE required practical?

Answer 1

To identify the presence of different nutrients in food samples.

Question 2

What reagent is used to test for reducing sugars?

Answer 2

Benedict’s solution.

Question 3

True or False: A positive test for reducing sugars will change the color of Benedict’s solution to brick red.

Answer 3

True.

Question 4

Fill in the blank: The test for starch is conducted using __________.

Answer 4

iodine solution.

Question 5

What color indicates a positive test for starch?

Answer 5

Blue-black.

Question 6

Which reagent is used to test for proteins?

Answer 6

Biuret reagent.

Question 7

What color change indicates a positive protein test?

Answer 7

Purple.

Question 8

What is the test for lipids?

Answer 8

Emulsion test.

Question 9

What indicates a positive lipid test?

Answer 9

A white emulsion forms.

Question 10

Which food test involves heating the sample?

Answer 10

Reducing sugars test with Benedict’s solution.

Question 11

True or False: Proteins can be tested with Benedict’s solution.

Answer 11

False.

Question 12

What is the first step in testing for starch?

Answer 12

Add a few drops of iodine solution to the food sample.

Question 13

What is the purpose of the emulsion test?

Answer 13

To detect the presence of lipids in a food sample.

Question 14

Fill in the blank: A positive test for reducing sugars is usually assessed after __________ minutes of heating.

Answer 14

2 to 5.

Question 15

What color will Benedict’s solution turn if no reducing sugars are present?

Answer 15

Blue.

Question 16

How can you confirm the presence of a fat in a food sample?

Answer 16

By observing a milky white emulsion after adding ethanol and water.

Question 17

What is the role of heat in the reducing sugars test?

Answer 17

It facilitates the reaction between the reducing sugars and Benedict’s solution.

Question 18

True or False: Lipids are soluble in water.

Answer 18

False.

Question 19

What safety precaution should be taken when performing food tests?

Answer 19

Wear safety goggles and gloves.

Question 20

What is the main component of Biuret reagent?

Answer 20

Copper sulfate.

Question 21

What is the procedure for testing for starch?

Answer 21

Add iodine solution to the food sample and observe the color change.

Question 22

True or False: The emulsion test can be used to test for carbohydrates.

Answer 22

False.

Question 23

What color indicates the presence of proteins when using Biuret reagent?

Answer 23

Purple.

Question 24

What type of carbohydrate can be tested using Benedict’s solution?

Answer 24

Reducing sugars.

Question 25

Fill in the blank: The presence of starch is indicated by a __________ color change.

Answer 25

blue-black.

Question 26

What happens to the iodine solution when starch is present?

Answer 26

It changes from brown to blue-black.

Question 27

What is the main purpose of the food tests in the AQA GCSE curriculum?

Answer 27

To enable students to identify nutrients in various food samples.

Question 28

What type of test detects the presence of glucose specifically?

Answer 28

Benedict's test.

Question 29

Fill in the blank: The test for proteins is known as the __________ test.

Answer 29

Biuret.

Question 30

What is the significance of the color change in food tests?

Answer 30

It indicates the presence or absence of specific nutrients.

Question 31

True or False: All food tests require heating the sample.

Answer 31

False.

Question 32

What is the final step in the lipid emulsion test?

Answer 32

Add water to the test tube after ethanol.

Question 33

What is the expected result when testing for proteins with Biuret reagent?

Answer 33

A color change to purple.