A chromatographic procedure separates 4.0 mg of unknown mixture on a column with a length of 40 cm and a diameter of 0.85 cm.

(a) What size column would you use to separate 100 mg of the same mixture?

(b) If the flow is 0.22 mL/min on the small column, what volume flow rate should be used on the large column?

(c) The mobile phase occupies 35% of the column volume. Calculate the linear velocity for the small column and the large column

(a) Find all equilibrium solutions for the equation

$$\frac{d y}{d x}=0.5 y(y-4)(2+y)$$

(b) With a calculator or computer, draw a slope field for this differential equation. Use it to determine whether each equilibrium solution is stable or unstable.

The 2', 3'-cyclic phosphodiester that is formed when RNA is hydrolyzed reacts with water, forming a mixture of nucleotide 2' - and 3'-phosphates. Propose a mechanism for this reaction.

If you dilute a can of orange juice that is $75 \mathrm{~mL}$ with enough water to make a total volume of $300 \mathrm{~mL}$, what is the percentage of juice in the mixture?

Fifty gallons of a $90 \%$ alcohol solution is obtained by mixing a $100 \%$ solution with a $75 \%$ solution. How many gallons of each solution must be used to obtain the desired mixture?

Classify substance Calcium chloride, used to melt ice on roads, consists of two elements, calcium and chlorine, in a fixed mass ratio as an element, compound, or mixture, and explain your answer.

When air is inhaled, it enters the alveoli of the lungs, and varying amounts of the component gases exchange with dissolved gases in the blood. The resulting alveolar gas mixture is quite different from the atmospheric mixture. The following table presents selected data on the composition and partial pressure of four gases in the atmosphere and in the alveoli:

$$\begin{array}{|c|c|c|c|c|} \hline \text { Gas } & \text { Mole \% } & \begin{array}{l} \text { Partial } \\ \text { Pressure (torr) } \end{array} & \text { Mole \% } & \begin{array}{l} \text { Partial } \\ \text { Pressure (torr) } \end{array} \\ \hline \mathrm{N}_2 & 78.6 & - & - & 569 \\ \hline \mathrm{O}_2 & 20.9 & - & - & 104 \\ \hline \mathrm{CO}_2 & 00.04 & - & - & 40 \\ \hline \mathrm{H}_2 \mathrm{O} & 00.46 & - & - & 47 \\ \hline \end{array}$$

If the total pressure of each gas mixture is $1.00 \mathrm{~atm}$, calculate:

(a) The partial pressure (in torr) of each gas in the atmosphere

(b) The mole % of each gas in the alveoli

(c) The number of $\mathrm{O}_2$ molecules in $0.50 \mathrm{~L}$ of alveolar air (volume of an average breath of a person at rest) at $37^{\circ} \mathrm{C}$

Use these words that end in the suffix -ure to answer the following questions.

mixture pleasure signature fracture

Which word can mean the result of being pleased? ________________________

Forty gallons of a $60 \%$ acid solution is obtained by mixing a $75 \%$ solution with a $50 \%$ solution. How many gallons of each solution must be used to obtain the desired mixture?

A mixture containing only Al$_2$O$_3$ (FM 101.96) and Fe$_2$O$_3$ (FM 159.69) weighs 2.019 g. When heated under a stream of H2, Al2O3 is unchanged, but Fe$_2$O$_3$ is converted into metallic Fe plus H$_2$O(g). If the residue weighs 1.774 g, what is the weight percent of Fe$_2$O$_3$ in the original mixture?

A gas mixture contains $1.5 \times 10^{-5}$ mole $\mathrm{CO}$ and has a total of 1 mole. What is the $\mathrm{CO}$ concentration in ppm$_{\mathrm{v}}$?

A mixture of nuts contains 1 cup of walnuts for every 3 cups of peanuts.

Write a linear equation that represents the relationship between peanuts, x, and walnuts, y.

Consider the ketones menthone and isomenthone. Propose an explanation for the observation that menthone is converted to a mixture of menthone and isomenthone on treatment with 90% sulfuric acid.

Determine equilibrium values for the given dynamical systems and state whether these equilibrium values are stable. a) $A_{n+1}=3 A_n-1$ b) $B_{n+1}=0.5 B_n-3$