Explain why the pH of a solution containing both acetic acid and sodium acetate is higher than that of a solution containing the same concentration of acetic acid alone.

Work this exercise without pencil and paper. Do not use a calculator.

Suppose two acid solutions are mixed. One is $26 \%$ acid and the other is $32 \%$ acid. Which one of the following concentrations cannot possibly be the concentration of the mixture?

A. $36 \%$

B. $28 \%$

C. $30 \%$

D. $31 \%$

Ascorbic acid (vitamin C) is a diprotic acid having the formula $\mathrm{H}_2 \mathrm{C}_6 \mathrm{H}_6 \mathrm{O}_6$. A sample of a vitamin supplement was analyzed by titrating a $0.1000 ~g$ sample dissolved in water with $0.0200 ~M$ $\mathrm{NaOH}$. A volume of $15.20 ~mL$ of the base was required to completely neutralize the ascorbic acid. What was the percentage by mass of ascorbic acid in the sample?

$\mathrm{H}_2 \mathrm{SO}_4$ is a strong acid but $\mathrm{HSO}_4^{-}$is a weak acid. Account for the difference in strength of these two related species.

Describe the effect of each of the following on the rate of the reaction of magnesium metal with a solution of hydrochloric acid: the molarity of the hydrochloric acid, the temperature of the solution, and the size of the pieces of magnesium.

Solve the following exercise.

Calculate the $K_{\mathrm{a}}$ of a weak acid if a 0.19- M aqueous solution of the acid has a pH of 4.52 at $25^{\circ} \mathrm{C}$

Assume you have a gram-negative bacterium that produces acid from lactose and cannot use citric acid as its sole carbon source. What is the bacterium?

Draw an optically active triglyceride that contains one palmitic acid residue and two myristic acid residues. Will this compound react with molecular hydrogen in the presence of a catalyst?

Choose the word or words that best complete the sentence. People who are descendants of a region's first inhabitants are ________ people. A. ruling B. religious C. indigenous D. conquering

Of all the nitrogenous wastes eliminated by animals, uric acid requires the least water to excrete. Why is the production of uric acid an advantage to animals that live on land ?

Hydrazoic acid,

$$HN_3$$

, is a weak acid. The

$$\left[ \mathrm { H } _ { 3 } \mathrm { O } ^ { - } \right]$$

of a 0.102 M solution of hydrazoic acid is

$$1.39 \times 10 ^ { - 3 } \mathrm { M }$$

. Determine the pH of this solution, and calculate

$$K_a$$

at

$$25 ^ { \circ } \mathrm { C }$$

for

$$\mathrm { HN } _ { 3 }$$

.

Formic acid (systematic name: methanoic acid) is a colorless liquid with a penetrating odor. It is the irritating ingredient in the bite of ants. Its chemical formula is HCOOH. Write the Lewis formula for a formic acid molecule. (Hint: Each of the atoms in the correct formula has a zero formal charge.)

Amy needs to make 10 L of 42% sulphuric acid solution. In the supply room, she finds bottles of 30% sulphuric acid solution and 60% sulphuric acid solution. What volume of each solution should she mix in order to make the 42% solution?

How many diff erent amino acids could theoretically be encoded by nucleic acids containing four diff erent nucleotides if (a) each nucleotide coded for one amino acid; (b) consecutive sequences of two nucleotides coded for one amino acid; (c) consecutive sequences of three nucleotides coded for one amino acid; (d) consecutive sequences of four nucleotides coded for one amino acid?