A compound contains only carbon, hydrogen, and oxygen. Combustion of \(10.68 \mathrm{mg}\) of the compound yields \(16.01 \mathrm{mg}\) \(\mathrm{CO}_{2}\) and \(4.37 \mathrm{mg} \mathrm{H}_{2} \mathrm{O} .\) The molar mass of the compound is \(176.1 \mathrm{g} / \mathrm{mol} .\) What are the empirical and molecular formulas of the compound?

Short Answer

Expert verified
The empirical formula of the compound is C₆H₈O₁₆, and the molecular formula is C₃H₄O₈.

Step by step solution

01

Calculate the moles of carbon and hydrogen

First, let's convert the mass of CO2 and H2O to moles. To do this, we need the molar masses of CO2 and H2O. The molar mass of CO2 is 12.01 g/mol (for C) + 2 * 16.00 g/mol (for O) = 44.01 g/mol. The molar mass of H2O is 2 * 1.01 g/mol (for H) + 16.00 g/mol (for O) = 18.02 g/mol. Now, let's convert the mass of CO2 and H2O to moles: - Moles of CO2 = (16.01 mg CO2) * (1 g / 1000 mg) * (1 mol CO2 / 44.01 g CO2) = \(3.636 \times10^{-4} mol\) - Moles of H2O = (4.37 mg H2O) * (1 g / 1000 mg) * (1 mol H2O / 18.02 g H2O) = \(2.427 \times10^{-4} mol\) Finally, let's determine the moles of carbon and hydrogen in the compound: - Moles of C = \(3.636 \times10^{-4} mol\) - Moles of H =\(2 \times 2.427 \times10^{-4} mol\) = \(4.854 \times10^{-4} mol\)
02

Calculate the moles of oxygen

We can find the moles of oxygen by using the initial moles of the compound. First, we need to convert the mass of compound to moles: - Moles of compound = (10.68 mg compound) * (1 g / 1000 mg) * (1 mol compound / 176.1 g compound) = \(6.063 \times 10^{-5} mol\) Since the combustion reaction is as follows: Compound + O₂ → CO₂ + H₂O Total moles of O atoms in the compound = (total moles of O atoms in CO₂) + (total moles of O atoms in H₂O) Let's find the total moles of O atoms in CO₂ and H₂O: - Moles of O in CO₂ = \(2 \times 3.636 \times 10^{-4} mol\) = \(7.273 \times 10^{-4} mol\) - Moles of O in H₂O = \(2.427 \times 10^{-4} mol\) Now, let's calculate the moles of O in the compound: - Moles of O = \(7.273 \times 10^{-4} mol + 2.427\times 10^{-4} mol\) = \(9.7 \times 10^{-4} mol\)
03

Determine the simplest whole-number ratio of elements (empirical formula)

Divide each number of moles by the smallest value to obtain the simplest whole-number ratio: \(C : \frac{3.636 \times10^{-4}}{6.063 \times 10^{-5}} = 6 ; H : \frac{4.854 \times10^{-4}}{6.063\times 10^{-5}} = 8 ; O : \frac{9.7 \times10^{-4}}{6.063\times 10^{-5}} = 16\) So, the empirical formula is C₆H₈O₁₆.
04

Determine the molecular formula

First, calculate the empirical formula mass: C₆H₈O₁₆: \(6(12.01)+8(1.01)+16(16.00) \approx 352.20\, g/mol \) Since the molar mass of the compound is about half of the empirical formula mass, the molecular formula should be half the empirical formula. Therefore, the molecular formula is C₃H₄O₈.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Elixirs such as Alka-Seltzer use the reaction of sodium bicarbonate with citric acid in aqueous solution to produce a fizz: $$\begin{aligned}3 \mathrm{NaHCO}_{3}(a q)+\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{7}(a q) & \longrightarrow \\\3 \mathrm{CO}_{2}(g)+3 \mathrm{H}_{2} \mathrm{O}(l) &+\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(a q)\end{aligned}$$ a. What mass of \(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{7}\) should be used for every \(1.0 \times 10^{2} \mathrm{mg} \mathrm{NaHCO}_{3} ?\) b. What mass of \(\mathrm{CO}_{2}(g)\) could be produced from such a mixture?

Natural rubidium has the average mass of 85.4678 u and is composed of isotopes \(^{85} \mathrm{Rb}\) (mass \(=84.9117 \mathrm{u}\) ) and \(^{87} \mathrm{Rb}\). The ratio of atoms \(^{85} \mathrm{Rb} /^{87} \mathrm{Rb}\) in natural rubidium is \(2.591 .\) Calculate the mass of \(^{87} \mathrm{Rb}\).

Ammonia is produced from the reaction of nitrogen and hydrogen according to the following balanced equation: $$\mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g) \longrightarrow 2 \mathrm{NH}_{3}(g)$$ a. What is the maximum mass of ammonia that can be produced from a mixture of \(1.00 \times 10^{3} \mathrm{g} \mathrm{N}_{2}\) and \(5.00 \times 10^{2} \mathrm{g} \mathrm{H}_{2} ?\) b. What mass of which starting material would remain unreacted?

Iron oxide ores, commonly a mixture of \(\mathrm{FeO}\) and \(\mathrm{Fe}_{2} \mathrm{O}_{3},\) are given the general formula \(\mathrm{Fe}_{3} \mathrm{O}_{4}\). They yield elemental iron when heated to a very high temperature with either carbon monoxide or elemental hydrogen. Balance the following equations for these processes: $$\begin{array}{c}\mathrm{Fe}_{3} \mathrm{O}_{4}(s)+\mathrm{H}_{2}(g) \longrightarrow \mathrm{Fe}(s)+\mathrm{H}_{2} \mathrm{O}(g) \\\\\mathrm{Fe}_{3} \mathrm{O}_{4}(s)+\mathrm{CO}(g) \longrightarrow \mathrm{Fe}(s)+\mathrm{CO}_{2}(g)\end{array}$$

Balance the following equations: a. \(\operatorname{Cr}(s)+\mathrm{S}_{8}(s) \rightarrow \mathrm{Cr}_{2} \mathrm{S}_{3}(s)\) b. \(\mathrm{NaHCO}_{3}(s) \stackrel{\text { Heat }}{\longrightarrow} \mathrm{Na}_{2} \mathrm{CO}_{3}(s)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) c. \(\mathrm{KClO}_{3}(s) \stackrel{\text { Heat }}{\longrightarrow} \mathrm{KCl}(s)+\mathrm{O}_{2}(g)\) d. \(\mathrm{Eu}(s)+\mathrm{HF}(g) \rightarrow \mathrm{EuF}_{3}(s)+\mathrm{H}_{2}(g)\)

See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free