Butylated hydroxytoluene, BHT, a food preservative, contains carbon, hydrogen, and oxygen. A sample of 15.42 milligrams of BHT was burned in a stream of oxygen and yielded 46.20 milligrams of $\mathrm{CO}_{2}(g)$ and 15.13 milligrams of $\mathrm{H}_{2} \mathrm{O}(g)$. Calculate the empirical formula of BHT.

Combustion analysis of a 1.000-gram sample of a compound known to contain only carbon, hydrogen, and iron produces 2.367 grams of $\mathrm{CO}_{2}(g)$ and 0.4835 grams of $\mathrm{H}_{2} \mathrm{O}(g)$. Determine the empirical formula of the compound.

Diethyl ether, often called simply ether, is a common solvent that contains carbon, hydrogen, and oxygen. A 1.23-gram sample was burned under controlled conditions to produce 2.92 grams of $\mathrm{CO}_{2}(g)$ and 1.49 grams of $\mathrm{H}_{2} \mathrm{O}(g)$. Determine the empirical formula of diethyl ether.

Graph each function. $f(x)=-\sqrt{x}-2$

Solve the equation using a bar model. $\frac{3}{4} x=8$

Compare the fractions in each pair. Think about how close the fractions are to $0, \frac{1}{2}, \text { or } 1$. a. $\frac{5}{8} \text { and } \frac{7}{12}$ b. $\frac{14}{15} \text { and } \frac{7}{8}$ c. $\frac{1}{9} \text { and } \frac{1}{23}$

A hemoglobin sample is found to be 0.373% iron by mass. Given that there are four iron atoms perhemoglobin molecule, determine the molecular mass of hemoglobin.

Use the following key to label each of the resources as land, labor, capital, or entrepreneurship. If a resource is land, identify it as either renewable or nonrenewable. If a resource is a capital good, identify it as either physical or human. (Hint: Physical capital is a tangible, human-made resource- such as tools or machinery-used to produce other goods and services. Ld-r = land (renewable), Ld-n = land (nonrenewable), Lbr = labor, C = capital, E = entrepreneurship. lawyer ____________

The formula of an acid is only partially known as $\mathrm{HXO}_{3}$. The mass of 0.0133 moles of this acid is 1.123 grams. Find the atomic mass of X and identify the element represented by X.

Rust occurs when iron metal reacts with the oxygen in the air. Chemical analysis shows that dry rust is 69.9% iron and 30.1% oxygen by mass. Determine the empirical formula of rust.

Use the Gauss-Jordan method to solve each system of equations. For systems in two variables with infinitely many solutions, give the solution with y arbitrary. For systems in three variables with infinitely many solutions, give the solution with z arbitrary.

$$\begin{aligned} &\frac{3}{8} x-\frac{1}{2} y=\frac{7}{8}\\ &-6 x+8 y=-14 \end{aligned}$$

An element forms chloride whose formula is $\ce{XCl4}$ that is known to consist of 74.8% chlorine by mass. Calculate the atomic mass of $\ce{X}$ and identify it.

Rewrite $\frac{2(x+5)-4}{2}-x$ using the fewest terms possible. Justify each step with a property or operation.

Combustion analysis of a 1.000-gram sample of a compound known to contain only carbon, hydrogen, and oxygen produces 1.500 grams of $\mathrm{CO}_{2}(g)$ and 0.409 grams of $\mathrm{H}_{2} \mathrm{O}(g)$. Determine the empirical formula of the compound.