BI101-Lab Notes

What is an acid?

Something that donates a proton [H+]

What does an acid do in a solution?

Increases the [H+]

What is the pH of acids?

Under 7

What is a base?

Something that accepts a proton [H+] or donates a hydroxide ion [OH-]

What does a base do in a solution?

Reduces the [H+]

What is the pH of bases?

Above 7

How do acids taste? How do bases taste?

Acids are sour, bases are bitter or soapy

What is odor of acids? What is the odor of bases?

Acids give a burning sensation, bases often don’t have an odor (except for ammonia)

What is the texture of acids? What is the texture of bases?

Acids are sticky, bases are slippery

What do acids react to? What do bases react to?

Acids react to metals to produce hydrogen gas, bases react with fats and oils

What does the pH scale measure?

The concentration of hydrogen ions in solution

How was the pH scale derived; mathematically or theoretically?

Mathematically

What is the equation for pH?

-log[H+]

Each level is ____ times more acidic

10

What is the pH of our brains?

7.2

What is the pH of our saliva?

6

What is the pH of our stomachs?

1.5-2

What is the pH of our intestines?

4-7

What is the pH of our blood?

7.4

What is a buffer?

A solution that is resistant to pH changes that has both a conjugate acid and base

What is special about the buffer?

It can accept and donate a proton depending on the environment

What is used to detect starch?

Potassium iodide

How is starch identified in a substance?

Potassium iodide changes the color of the substance when starch is present

What do reducing sugars do?

Donate electrons to another molecule, can be used directly for energy, and break down non-reducing sugars

What must the Benedict’s Test do to have an effect?

Boil

What does boiling do for the Benedict’s Test?

Adds energy to the system

What does the Benedict’s Test produce?

The chemical reaction oxidizes the potassium thiocyanate, resulting in a precipitate and color change

What does the Sudan test test for?

Lipids

What is special about the powder used in the Sudan test?

It is lipid soluble

What are proteins made of?

Amino acids

What are the functions of proteins (remember THESE)?

Transport Hormone Enzymes Signaling Energy

What does “blue” signal in the Buriet Test?

Negative, proteins are absent

What does “deep purple” signal in the Buriet Test?

Positive, proteins are present

Is vitamin C a macromolecule?

No

What does Vitamin C do?

It is a cofactor for metabolism, an essential nutrient, and is needed for biosynthesis

Are chloride ions macromolecules?

No

What forms when silver nitrate is in the presence of ions?

A precipitate