Water, pH + Buffers Flashcards
What do strong acids do in water?
What is produced?
They completely dissociate!
A proton
A proton acceptor is called a…
A base
A proton donator is called a…
An acid
What is physiological ph?
7.4 (within 0.3 either side of that, + or -)
pH is a measure of what?
Protons
What are the units of the concentration of protons in pH?
Molar - M
What solution can resist changes to pH?
A buffer
At what point does a conjugate base EQUAL a conjugate acid?
pKa
What is the pKa when the buffering region is 4.5 to 6.5?
5.5 (buffering region is pKa + or - 1)
pH of a lysosome is…
About 4.5
The hydrogen phosphate system controls the pH of what?
Cellular pH!
The bicarbonate system controls the pH of…
Blood + Gastric Acid
What % of the brain is water?
75%
Are hydrogen bonds unique to water?
NO - there are many variations!
E.g. Nitrogen can be involved or any other electronegative atom.
A reaction where 2 molecular fragments are joined and H20 is PRODUCED is called a …
Condensation Reaction
Hydrolysis is when water is LOST
To be soluble in water, the solute must be…
Polar or charged! (Hydrophilic)
What is the predominant form of water at room temperature?
H2O
pH of pure water is 7.
In the lab, distilled water is often pH 5.5-6.5
Why?
It reacts with CO2 in the air as we are NOT in a vacuum. And this forms carbonic acid.
Stomach acid is composed of 0.05 - 0.1 M HCL = pH 1-1.3
The pH of stomach (gastric acid) is pH 1.5-3.5. Why?
There are cells within our stomach (goblet cells) that produce bicarbonate (a base) which acts as a BUFFER.
This ensures that the stomach does NOT become too acidic!
In a highly basic solution, pH = 13, the dominant form of glycine is:
NH2 - CH3+ - COO-
How much glucose (in grams) do you need to make 100mL of a 1M solution. The FW of glucose is 180g mol-1.
W = 180g V = 0.1L (convert the 100mL to litres!) M = 1M
Multiply them all together:
180 x 0.1 x 1 = 18g!
