lab exercise 3
Using the terms provided, complete the paragraph about determining the pH value for substances. Not all terms will be used.
Many tests can determine a pH value, but among the more interesting are colorimetric tests in which an indicator chemical changes color when it reacts. Many plant pigments, especially anthocyanins, can be used as colorimetric pH indicators. One that works well is the red pigment in red cabbage.
Which of the following solutions has the greatest H+ concentration?
Solution with pH 2
Demonstrate understanding of identifying an unknown compound by clicking the box(es) that you would need to do.
Test the compound using the test for sugars. Test the compound using the test for proteins. Test the compound using the test for lipids. Test the compound using the test for starch.
Using the terms provided, complete the sentences about organic molecules.
The organic molecules (biomolecules) tested for in Lab Exercise 3 include carbohydrates, lipids, and proteins. Carbohydrates are used to supply quick energy to our cells. The polysaccharide starch is composed of monosaccharide building blocks. Lipids include fats, phospholipids, and steroids that provide some cellular structure and energy for cells. The building blocks for lipids include fatty acids and glycerol. Proteins compose important cellular structures, antibodies, and enzymes. Amino acids are the building blocks of proteins.
A person's blood pH of 7.20 is considered acidosis, even though this pH is above 7 on the pH scale. Identify the best explanation as to why by clicking the box(es) provided.
The regular pH for human blood is 7.4. If a person's blood were to be different than that, then it is obvious they have a condition. Blood is a bodily fluid that has a specific level range, so if the pH is different by any change of number, then this means that there has been an increase or decrease in hydrogen ion concentration.
You are given a test tube with 3 mL of a light colored unknown substance in it and told to add several drops of iodine to it. After you swirl the tube to mix in the iodine you notice no change in color. What can you conclude about this test you just performed?
The unknown substance contains no starch.
The building block of a protein is
amino acid
What indicator is used to test for sugars (monosaccharides)?
benedict's solution
A positive test for starch, when using iodine, was a color change to
blue/black
Identify what would be common results from the cabbage water tests by clicking and dragging the labels representing color and pH to the appropriate location on the data table. (You may be using a label more than once.)
cabbage water: purple, neutral distilled water: vinegar: red, acid baking soda: blue/green, basic
Analyze the results you observed from the pH paper tests. Then, compare distilled water and tap water by clicking and dragging the labels to the correct location. (Not all labels will be used.)
distilled water: ph:7.0, pure water with neutral ph tap water: ph: 6-8.5, dissolved substances may include in acidic or basic pH
The most basic unit of matter is
element
Which of the following would be an example of a lipid?
fat
If a person were on a low-carbohydrate, high-protein diet, which of the six substances tested would the person want to increase? Explain your answer.
if a person were on a low-carbohydrate, and a high protein diet, they should get tested for high cholesterol????
Which of the following pH numbers would represent the strongest acid?
1
Which number would represent a strong acid pH?
2
Select the substances to match their correct pH value.
2.0 - Gastric juice 3.0 - Apple juice 3.8 - Vaginal secretions 4.2 - Tomato juice 6.5 - Milk 7.4 - Blood 7.5 - Semen 18.0 - Egg white 11.5 - Household ammonia 13.4 - Oven cleaner
The pH of distilled water is
7
Which number would represent a neutral pH?
7
What indicator is used to test for proteins?
Biuret reagent
The test to indicate the presence of starch uses which substance?
IKI (iodine solution)
What indicator is used to test for starch?
Iodine
The building block of a carbohydrate is
monosaccharide (simple sugar)
A positive test for lipids results in a
pinkish color change.
The building block of a carbohydrate is
simple sugars (monosaccharides)
What indicator is used to test for lipids?
sudan iv
According to the pH scale, the lower the pH,
the more the H+ concentration increases.
