Acids and Bases

Homeostasis means:  a.  That a population changes over time b.  That conditions are held constant and do not change c.  That cells have enough water d.  That all organisms require an energy source e.  That conditions remain within a constant range

An acid:  a. Has a value above seven on the pH scale b. Is a chemical that takes hydrogen ions from a solution c. Has a value of seven on the pH scale d. Is a chemical that adds hydrogen ions to a solution e. All are correct

A base:  a. Has a value of 7 on the pH scale b. Is a chemical that adds hydrogen ions to a solution c. Is a chemical that absorbs hydrogen ions from a solution d. Has a value below 7 on the pH scale

A substance having a pH of 2 would best be described as:  a. Neutral b. A weak acid c. A weak base d. A strong base e. A strong acid

A substance having a pH of 6 would best be described as:  a. A weak acid b. Neutral c. A weak base d. A strong acid e. A strong base

A substance having a pH of 7 would best be described as:  a. A weak acid b. A weak base c. Neutral d. A strong acid e. A strong base

A substance having a pH of 8 would best be described as:  a. Neutral b. A weak base c. A weak acid d. A strong acid e. A strong base

A substance having a pH of 13 would best be described as:  a. A weak acid b. A weak base c. Neutral d. A strong acid e. A strong base

What is the arrow pointing to? a) electron b) hydroxide ion c) water molecule d) hydronium ion e) hydrogen ion

What is the arrow pointing to? a) hydrogen ion b) hydroxide ion c) water d) hydronium ion e) proton

In a neutral solution the concentration of __________.a) hydrogen ions is less than the concentration of hydroxide ionsb) water molecules is less than the concentration of hydroxide ionsc) water molecules is less than the concentration of hydrogen ionsd) hydrogen ions is greater than the concentration of hydroxide ionse) hydrogen ions is equal to the concentration of hydroxide ions. 

The molar ratio of HPO42- to H2PO4- in a solution is 1.4. What is the pH of the solution? Phosphoric acid (H3PO4) is a triprotic acid, with 3 pKa values: 2.14, 6.86, and 12.4.A. 2.3B. 12.5C. 7.0D. 6.2

In our discussion of the acid-base properties of individual amino acids, we indicated that most amino acids will be electrically neutral over a very broad range of pH values, so that the pI of an individual amino acid is a nearly meaningless quantity. By contrast, a full-length protein will be electrically neutral over a relatively narrow pH range — typically less than one pH unit. Thus the pI of a protein is a well-defined quantity. Why is this?

Formic acid has a pKa of 3.75; acetic acid has a pKa of 4.76. Which is the stronger acid? Does the stronger acid have a greater or lesser tendency to lose its proton than the weaker acid?

What is the pH of 40.0mL of a solution that is 0.13 M CN- and 0.21 M in HCN? For HCN, use Ka = 4.9 x 10-9.

What are the concentrations of acetic acid (pKa = 4.76) and acetate in a buffer solution of 0.20M at pH 4.5? Enter your answer to two significant figures.