Find the hydronium ion $\left[\mathrm{H}_3 \mathrm{O}^{+}\right]$concentration for the substance with the given p H. Wine, 3.4

Superoxide ion is toxic to strict anaerobes because they lack a. catalase $\hspace{2.4cm}$ c. dismutase b. peroxidase $\hspace{2cm}$ d. oxidase

Obtain a. the $K_b$ value for $\mathrm{NO}_2{ }^{-} ;$ b. the $K_a$ value for $\mathrm{C}_5 \mathrm{H}_5 \mathrm{NH}^{+}$(pyridinium ion).

Does ion movement through certain types of gated channels only occur when a neurotransmitter is bound to that channel? Why or why not?

The pH of a substance is a measure of its acidity. The pH scale ranges from 0 to 14, with a pH of 7 being neutral. As the pH decreases, the substance is more acidic. The table shows the pH of several common substances.

$$\begin{array}{|l|l|c|c|} \hline {} & {\text { Substance }} & {\text { pH }} & \begin{array}{c} \text { Hydrogen lon } \\ \text { Concentration } \end{array} \\ \hline {\text { Acids }} & \text { coffee } & 5 & 10^{-5} \\ { 2 - 4 } & \text { milk } & 6 & 10^{-6} \\ \hline \text { Neutral } & \text { pure water } & 7 & 10^{-7} \\ \hline {\text { Bases }} & \text { egg whites } & 8 & 10^{-8} \\ { 2 - 4 } & \text { baking soda } & 9 & 10^{-9} \\ \hline \end{array}$$

a. Which substance in the table has the greatest hydrogen ion concentration? How many times as great is that hydrogen ion concentration than that of egg whites? b. Which substance has a hydrogen ion concentration of one millionth? c. How many times as great is the hydrogen ion concentration of coffee as the hydrogen ion concentration of pure water?

What is the molar hydronium ion concentration in solutions with each of the following pH values?

a. 2.05

b. 4.88

c. 6.75

d. 11.33

When consumption is a positive amount, saving:

a. must be a negative amount.

b. must also be a positive amount.

c. can be either a positive or a negative amount.

d. is zero.

Calculate the hydrogen ion concentration and the $\mathrm{pH}$ of the following solutions of strong acids.

a. $1.04\times 10^{-4}~M\mathrm{~HCl}$

Calculate the hydrogen ion concentration and the $\mathrm{pH}$ of the following solutions of strong acids.

b. $3.0 \times 10^{-5}~M\mathrm{~HCl}$

Explain why secretin production in response to acidic chyme and its stimulation of bicarbonate ion secretion constitute a negative-feedback mechanism.

The Mg$^{2+}$ and Na$^+$ ions each have ten electrons. Which ion would you expect to have the smaller radius? Why?

(a) Find the form of all positive integers $n$ satisfying $\tau(n)=10 .$ What is the smallest positive integer for which this is true? (b) Show that there are no positive integers $n$ satisfying $\sigma(n)=10$ .

Use data from Appendix $D$ to determine whether the ion product of water, $K_w$, increases, decreases, or remains unchanged with increasing temperature.

If $a$ and $b$ are related so that $a+b>a-b$, which statement must be true about $a$ and $b$ ?

$\mathrm{F} \ a$ is greater than $b$.

$\mathrm{G} \ a$ is a negative number and $b$ is a positive number.

$\mathrm{H} \ b$ is a negative number and $a$ is a positive number.

$\mathrm{J} \ a$ and $b$ are a positive numbers .