Evaluate by using the order of operation: $(2^2+8)\div 4-2$

The equation for the reaction of iron and oxygen gas to form rust $\left(\mathrm{Fe}_2 \mathrm{O}_3\right)$ is written as

$$4 \mathrm{Fe}(s)+3 \mathrm{O}_2(g) \longrightarrow 2 \mathrm{Fe}_2 \mathrm{O}_3(s) \quad \Delta H=-1.7 \times 10^3 \mathrm{~kJ}$$

How many grams of rust form when 150 kJ are released?

Predict how the relative volumes of the large intestines of herbivores and carnivores would compare, and explain your reasoning.

Two cars are headed south on the highway at different speeds. Starting when the faster car pulls alongside the slower car, one of the cars accelerates northward for 5.0 s and the other accelerates southward for 5.0 s. At the end of that 5.0-s interval, the two cars have the same speed. Which car is now ahead?

Billions of neutrinos continually pass through each square centimeter of your body each second. Why don’t you notice them?

Express the answers to these operations in scientific notation:
(a) $0.0095+\left(8.5 \times 10^{-3}\right)$
(b) $653 \div\left(5.75 \times 10^{-8}\right)$
(c) $850,000-\left(9.0 \times 10^5\right)$
(d) $\left(3.6 \times 10^{-4}\right) \times\left(3.6 \times 10^6\right)$

In a right triangle, the measure of one acute angle is twice the sum of the measure of the other acute angle and 30. Find the measure of each acute angle in the right triangle.

Simplify the given expression to one of the three primary trigonometric functions, $\sin x, \cos x$, or $\tan x$.

$$\dfrac{\sec ^2 x \cos x}{\csc x}$$

Personal consumption expenditures (in billions of dollars) for several types of recreation from 2012 through 2017 are shown in the table, where $x$ is the expenditures on amusement parks and campgrounds, $y$ is the expenditures on live entertainment (excluding sports), and $z$ is the expenditures on spectator sports.

A model for the data is given by

z = 0.54x - 0.6y + 11.98

Find $\frac{\partial z}{\partial x}$ and $\frac{\partial z}{\partial y}$.

The reaction

$$2 \mathrm { Fe } _ { 2 } \mathrm { O } _ { 3 } ( s ) + 3 \mathrm { C } ( s ) \longrightarrow 4 \mathrm { Fe } ( s ) + 3 \mathrm { CO } _ { 2 } ( g )$$

is involved in the smelting of iron. Use

$$\Delta H _ { f }$$

values given in Appendix Table B–14 to calculate the enthalpy change during the production of 1 mol of iron.

Repeating a pair of ice tongs is shown in the figure. The ice weighs $50 \mathrm{~lb}$ and is $10 \mathrm{~in}$ wide across the tongs. The distance between the handles is $4 \mathrm{~in}$, and the mean radius $r$ of a tong is $6 \mathrm{~in}$. The rectangular cross-sectional dimensions are $0.750 \mathrm{~in}$ deep $\times 0.312 \mathrm{~in}$ wide. Determine the safety factor for the tongs if their $S_{y}=30 \mathrm{~kpsi}$.with the tongs made of Class 20 gray cast iron.

a. List and briefly describe three major parts of the lithosphere.
b. Which layer serves as the main storehouse of chemical resources used in manufacturing consumer products ?

Calculate the amount concentration of the cations in the following solutions:

(a) $0.5 \mathrm{~mol} / \mathrm{L}$ sodium carbonate, $\mathrm{Na}_2 \mathrm{CO}_3$

(b) $0.2 \mathrm{~mol} / \mathrm{L}$ ammonium sulfite, $\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_3$

(c) $1.5 \mathrm{molL}$ iron(III) sulfate, $\mathrm{Fe}_2\left(\mathrm{SO}_4\right)_3$

For the given problem, determine the equations of the polynomials of degree two whose graphs pass through the given points.

$$(-1,-1),(0,1),(1,-3)$$

Determine the value of $y$ when $x=3.$