Hydrocarbon mixtures are used as fuels. (a) How many grams of $\mathrm{CO}_{2}(g)$ are produced by the combustion of $200 . \mathrm{g}$ of a mixture that is 25.0$\% \mathrm{CH}_{4}$ and 75.0$\% \mathrm{C}_{3} \mathrm{H}_{8}$ by mass? (b) $\mathrm{A} 252-\mathrm{g}$
gaseous mixture of $\mathrm{CH}_{4}$ and $\mathrm{C}_{3} \mathrm{H}_{8}$ burns in excess $\mathrm{O}_{2},$ and 748 $\mathrm{g}$ of $\mathrm{CO}_{2}$ gas is collected. What is the mass $\%$ of $\mathrm{CH}_{4}$ in the mixture?

nutrients in plant fertilizers. By industry convention, the numbers on a label refer to the mass percents of $\mathrm{N}, \mathrm{P}_{2} \mathrm{O}_{5},$ and $\mathrm{K}_{2} \mathrm{O}$ , in that order.
Calculate the N/P/K ratio of a 30$/ 10 / 10$ fertilizer in terms of moles of each element, and express it as $x / y / 1.0 .$

What mass percents of ammonium sulfate, ammonium hydrogen phosphate, and potassium chloride would you use to prepare 10$/ 10 / 10$ plant fertilizer (see Problem 3.122$) ?$

Ferrocene, synthesized in 1951 , was the first organic iron compound with Fe $-\mathrm{C}$ bonds. An understanding of the structure of ferrocene gave rise to new ideas about chemical bonding and ed to the preparation of many useful compounds. In the combustion analysis of ferrocene, which contains only $\mathrm{Fe}, \mathrm{C},$ and $\mathrm{H}, \mathrm{a}$ 0.9437 - g sample produced 2.233 $\mathrm{g}$ of $\mathrm{CO}_{2}$ and 0.457 $\mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O}$ .
What is the empirical formula of ferrocene?

When carbon-containing compounds are burned in a limited amount of air, some $\mathrm{CO}(g)$ as well as $\mathrm{CO}_{2}(g)$ is produced. A gaseous product mixture is 35.0 mass $\% \mathrm{CO}$ and 65.0 mass $\% \mathrm{CO}_{2} .$ What is the mass $\%$ of $\mathrm{C}$ in the mixture?