What chemicals can be detected in urine?

Directions:

1) On a separate sheet of paper, copy the following table leaving enough room in each block to write a detailed description of the solutions that are tested.

Test Solution

/ Description of Solution Before Testing / Description of Solution After Testing / Substance in Solution
Solution 1

2) Obtain a test tube rack with 4 test tubes on it.

3) Using tape, label each test tube as follows: Solution 1, Solution 2, Solution 3, Solution 4

4) Follow the steps below for each Test Solution.

Test for Solution 1

- Using the eye dropper given, place 3 full eyedroppers into the test tube labeled Solution 1.

- Describe the appearance of the liquid in the test tube (yellow, white, cloudy, transparent, etc) and place the information in your chart

- Add 15 drops of Benedict’s solution to the test tube

- Place the test tube in the warm water bath (beaker of water on the hot plate) for about 5 minutes.

- Take the test tube out of the warm water bath and place in the test tube rack.

- Describe the appearance of the liquid after testing and place the information in your chart.

Test for Solution 2

- Using the eye dropper given, place 3 full eyedroppers into the test tube labeled Solution 2.

- Describe the appearance of the liquid in the test tube (yellow, white, cloudy, transparent, etc) and place the information in your chart

- Add 15 drops of Biuret Solution to the test tube

- Place in the test tube rack.

- Describe the appearance of the liquid after testing and place the information in your chart.

Test for Solution 3

- Using the eye dropper given, place 3 full eyedroppers into the test tube labeled Solution 3.

- Describe the appearance of the liquid in the test tube (yellow, white, cloudy, transparent, etc) and place the information in your chart

- Your teacher will add 2 drops of Silver Nitrate to the test tube containing Silver Nitrate. Silver Nitrate is a strong poison and irritant. Rinse skin immediately if contact is made.

- Place in the test tube rack.

- Describe the appearance of the liquid after testing and place the information in your chart.

Test for Solution 4

- Using the eye dropper given, place 3 full eyedroppers into the test tube labeled Solution 4.

- Describe the appearance of the liquid in the test tube (yellow, white, cloudy, transparent, etc) and place the information in your chart

- Add 2 drops of Iodine-Potassium-Iodine Solution (IKI) to the test tube

- Place in the test tube rack.

- Describe the appearance of the liquid after testing and place the information in your chart.

Substances in Solution

Directions: Given the following descriptions of substances and their reactions to certain chemicals, determine which substance was in each test solution. Place the correct substance in your table.

- If salt is present in urine, the urine will form a white cloudy precipitate that sometimes settles to the bottom.

- If sugar is present, the urine will turn a red-orange color when heated.

- If protein is present, the urine will turn a cloudy white color from its normal yellow tinge.

- If starch is present, the urine will turn a dark almost black color.

Discussion Questions

1) What four (4) substances did you test for in this lab?

2) How can you tell if a liquid contains salt?

3) How can you tell if a liquid contains a sugar, like glucose or dextrose?

4) Why is it useful to know if urine contains salt or sugars?

5) When testing a sample of someone’s urine, the doctor notices that it becomes very dark during one test and forms a white precipitate in another. Which substances are in the urine? Which substances are not in the urine? According to the examples in this lab.

6) What organ in your body is the main excretory organ?

7) Each kidney contains about a million tiny filters called what?