Which of the following statements best describes a system at equilibrium?

1)Equilibrium is obtained when the concentrations of reactants are less than the concentration of products.

2)Equilibrium is obtained when the concentrations of reactants and products are both zero.

3)Equilibrium is obtained when the concentrations of reactants and products are constant.

4)Equilibrium is obtained when the concentrations of reactants and products are equal.

What chemical test will distinguish between the compounds in each of the following pairs? Indicate what is visually observed with each test. (Hint: Make a list of tests you have learned from this chapter and previous chapters for identifying the functional groups in these compounds.) a. phenol and anisole. b. 1-butanol and methyl propyl ether. c. dipropyl ether and hexane. d. ethyl phenyl ether and allyl phenyl ether.

When a chemical system has reached equilibrium, the concentrations of all reactants and products remain___ with time.

Solve each problem. 46 is what percent of 115?

Select all the true statements regarding chemical equilibrium.

At equilibrium...

the concentrations of reactants and products are equal.

the concentrations of reactants and products remain constant.

reactants are still being converted to products (and vice versa).

the rates of the forward and reverse reactions are equal.

A $2.0 \mathrm{~kg}$ object is moving to the right with a speed of $1.0 \mathrm{~m} / \mathrm{s}$ when it experiences the force What are the object's speed and direction after the force ends?

Clarice Johnson put 1,489 miles on her car in June. Of those miles, $27 \%$ were for her job. The company reimburses Clarice $\$ 0.35$ a mile for business use. What did Clarice receive as reimbursement for the use of her car in June?

(a) The data from a sedimentation equilibrium experiment performed at $300 \mathrm{~K}$ on a macromolecular solute in aqueous solution show that a graph of $\ln c$ against $r^2$ is a straight line with a slope of $729 \mathrm{~cm}^{-2}$. The rotational rate of the centrifuge was 50000 r.p.m. The specific volume of the solute is $0.61 \mathrm{~cm}^3 \mathrm{~g}^{-1}$. Calculate the molar mass of the solute.

(b) The data from a sedimentation equilibrium experiment performed at $293 \mathrm{~K}$ on a macromolecular solute in aqueous solution show that a graph of $\ln c$ against $(r / \mathrm{cm})^2$ is a straight line with a slope of 821 . The rotation rate of the centrifuge was $1080 \mathrm{~Hz}$. The specific volume of the solute is $7.2 \times 10^{-4} \mathrm{~m}^3 \mathrm{~kg}^{-1}$. Calculate the molar mass of the solute.

The average of two nonnegative numbers is $180.$ What is the largest possible product of these two numbers?

Stock Prices A random sample of stock prices per share (in dollars) is shown. Find the $90 \%$ confidence interval for the variance and standard deviation for the prices. Assume the variable is normally distributed. \

$$\begin{array}{rrrr}26.69 & 13.88 & 28.37 & 12.00 \\ 75.37 & 7.50 & 47.50 & 43.00 \\ 3.81 & 53.81 & 13.62 & 45.12 \\ 6.94 & 28.25 & 28.00 & 60.50 \\ 40.25 & 10.87 & 46.12 & 14.75 \\ \end{array}$$

Imagínate que tú y un(a) amigo(a) trabajaron toda la noche para acabar el proyecto. Explícales a otros amigos por qué tuvieron que terminarlo para ese día. Usa las siguientes expresiones: era importante, era necesario, era posible y era probable.

A constant force has a magnitude of $20$ newtons and acts in the direction of the vector $\mathbf{a}=2\mathbf{i}-\mathbf{j}+3\mathbf{k}$. If this force moves a particle along the line segment from $(1,2,1)$ to $(2,1,4)$ and the distance is measured in meters, find the work done by the force.

In this problem solve the given equation.

$$|4 x-1|=2$$

Integrate in problem. $\int 3 \sin ^{2} x d x$.