Dry air is essentially a mixture of the following entities: $\mathrm{N}_2, \mathrm{O}_2, \mathrm{Ar}$, and $\mathrm{CO}_2$. The composition of dry air, in mole percent, is $78.08 \% \mathrm{~N}_2, 20.95 \% \mathrm{O}_2, 0.93 \% \mathrm{Ar}$, and $0.04 \% \mathrm{CO}_2$. What is the mass, in grams, of a sample of air that contains exactly one mole of the entities?

All-purpose fertilizers contain the essential elements nitrogen, phosphorus, and potassium. A typical fertilizer carries numbers on its label, such as "5-10-5". These numbers represent the $\% \mathrm{~N}$, $\% \mathrm{P}_2 \mathrm{O}_5$, and $\% \mathrm{~K}_2 \mathrm{O}$, respectively. The $\mathrm{N}$ is contained in the form of a nitrogen compound, such as $\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4, \mathrm{NH}_4 \mathrm{NO}_3$, or $\mathrm{CO}\left(\mathrm{NH}_2\right)_2$ (urea). The $\mathrm{P}$ is generally present as phosphate, and the $\mathrm{K}$ as $\mathrm{KCl}$. The expressions $\% \mathrm{P}_2 \mathrm{O}_5$ and $\% \mathrm{~K}_2 \mathrm{O}$ were devised in the nineteenth century, before the nature of chemical compounds was fully understood. To convert from $\% \mathrm{P}_2 \mathrm{O}_5$ to $\mathrm{P}_2 \mathrm{O}_5$ and $2 \mathrm{~mol} \mathrm{~K} / \mathrm{mol} \mathrm{K} / \mathrm{O}$ must be used, $2 \mathrm{~mol} / \mathrm{mol}$ with molar masses. Assuming three-significant-figure precision, what is the percent composition of the "5-10-5" fertilizer in $\% \mathrm{~N}, \% \mathrm{P}$, and $\% \mathrm{~K}$ ?

A $1.562 \mathrm{~g}$ sample of the alcohol $\mathrm{CH}_3 \mathrm{CHOHCH}_2 \mathrm{CH}_3$ is burned in an excess of oxygen. What masses of $\mathrm{CO}_2$ and $\mathrm{H}_2 \mathrm{O}$ should be obtained?

$Para$-cresol ( $p$-cresol) is used as a disinfectant and in the manufacture of herbicides. A $0.4039 \mathrm{~g}$ sample of this carbon-hydrogen-oxygen compound yields $1.1518 \mathrm{~g} \mathrm{CO}_2$ and $0.2694 \mathrm{~g} \mathrm{H}_2 \mathrm{O}$ in combustion analysis. Its molecular mass is $108.1 \mathrm{u}$. For $p$-cresol, determine its molecular formula.

$Para$-cresol ( $p$-cresol) is used as a disinfectant and in the manufacture of herbicides. A $0.4039 \mathrm{~g}$ sample of this carbon-hydrogen-oxygen compound yields $1.1518 \mathrm{~g} \mathrm{CO}_2$ and $0.2694 \mathrm{~g} \mathrm{H}_2 \mathrm{O}$ in combustion analysis. Its molecular mass is $108.1 \mathrm{u}$. For $p$-cresol, determine its mass percent composition

$Para$-cresol ( $p$-cresol) is used as a disinfectant and in the manufacture of herbicides. A $0.4039 \mathrm{~g}$ sample of this carbon-hydrogen-oxygen compound yields $1.1518 \mathrm{~g} \mathrm{CO}_2$ and $0.2694 \mathrm{~g} \mathrm{H}_2 \mathrm{O}$ in combustion analysis. Its molecular mass is $108.1 \mathrm{u}$. For $p$-cresol, determine its empirical formula

A compound of carbon and hydrogen consists of $94.34 \% \mathrm{C}$ and $5.66 \% \mathrm{H}$, by mass. The molecular mass of the compound is found to be $178 \mathrm{u}$. What is its molecular formula?

For the mineral torbernite, $\mathrm{Cu}\left(\mathrm{UO}_2\right)_2\left(\mathrm{PO}_4\right)_2 \cdot 8 \mathrm{H}_2 \mathrm{O}$, determine the mass required to contain $1.00 \mathrm{~g} \mathrm{P}$

For the mineral torbernite, $\mathrm{Cu}\left(\mathrm{UO}_2\right)_2\left(\mathrm{PO}_4\right)_2 \cdot 8 \mathrm{H}_2 \mathrm{O}$, determine the element present in the greatest mass percent

For the mineral torbernite, $\mathrm{Cu}\left(\mathrm{UO}_2\right)_2\left(\mathrm{PO}_4\right)_2 \cdot 8 \mathrm{H}_2 \mathrm{O}$, determine the ratio, by mass, of $\mathrm{Cu}$ to $\mathrm{P}$

For the mineral torbernite, $\mathrm{Cu}\left(\mathrm{UO}_2\right)_2\left(\mathrm{PO}_4\right)_2 \cdot 8 \mathrm{H}_2 \mathrm{O}$, determine the ratio, by number, of $\mathrm{H}$ atoms to $\mathrm{O}$ atoms

For the mineral torbernite, $\mathrm{Cu}\left(\mathrm{UO}_2\right)_2\left(\mathrm{PO}_4\right)_2 \cdot 8 \mathrm{H}_2 \mathrm{O}$, determine the total number of atoms in one formula unit

Explain whether the given statement is correct concerning sorbic acid, $\mathrm{C}_6 \mathrm{H}_8 \mathrm{O}_2$, an inhibitor of mould and yeast.

It has four times as many $\mathrm{H}$ atoms as $\mathrm{O}$ atoms, but four times as much $\mathrm{O}$ as $\mathrm{H}$ by mass

In white phosphorus, $P$ atoms are joined into $P_4$ molecules (see Figure 3-5). White phosphorus is commonly supplied in chalk-like cylindrical form. Its density is $1.823 \mathrm{~g} / \mathrm{cm}^3$. For a cylinder of white phosphorus $6.50 \mathrm{~cm}$ long and $1.22 \mathrm{~cm}$ in diameter, determine the total number of $\mathrm{P}$ atoms.