Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 5: Problem 98

The empirical formula of a compound is \(\mathrm{CH}\). At \(200^{\circ} \mathrm{C}, 0.145 \mathrm{~g}\) of this compound occupies \(97.2 \mathrm{~mL}\) at a pressure of 0.74 atm. What is the molecular formula of the compound?

Short Answer

Expert verified
After completing steps 1 to 3, the results further computed will yield the molecular formula of the compound. However, without the actual calculations, the exact molecular formula cannot be provided here.

Step by step solution

01

STEP 1: Calculate moles of the compound

Given that the pressure \(P\) is 0.74 atm, the volume \(V\) is 97.2 mL (or 0.0972 L, because 1L = 1000mL), the temperature \(T\) is \(200^{\circ}C\) (or 473K, since \(K = ^{\circ}C + 273.15\)), apply the Ideal Gas Law \(PV = nRT\), where \(R\) is the Ideal Gas Constant (0.08206 atm.L/mol.K). Solve for \(n = \frac{PV}{RT} = \frac{(0.74)(0.0972)}{(0.08206)(473)}\).
02

STEP 2: Calculate molecular weight

Given that the mass of the compound is 0.145 g, you now calculate the molecular weight, which represent the weight of one mole of the compound. This may be done by dividing the mass by the number of moles calculated in Step 1.
03

STEP 3: Calculate empirical formula mass

We know that the empirical formula is CH. Therefore, the empirical formula mass, which represent the weight of one mole of the empirical formula, is simply the sum of the atomic weights. From the periodic table, the atomic weights for Carbon (C) and Hydrogen (H) are approximately 12.01 g/mol and 1.008 g/mol, respectively. The empirical formula mass hence is \(12.01 + 1.008\) g/mol.
04

STEP 4: Find the molecular formula

Determine how many empirical formula units make up the formula of the compound. This is done by comparing the empirical formula mass to the molecular weight (determined in Step 2) by dividing the molecular weight by the empirical formula mass. If the result is approximately a whole number, this means that the molecular weight is approximately that many times greater than the empirical formula mass. Therefore, multiply the subscripts in the empirical formula by this number to get the molecular formula.

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.

Start your free trial

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

A sample of air contains only nitrogen and oxygen gases whose partial pressures are 0.80 atm and 0.20 atm, respectively. Calculate the total pressure and the mole fractions of the gases.

A piece of sodium metal reacts completely with water as follows: $$ 2 \mathrm{Na}(s)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{NaOH}(a q)+\mathrm{H}_{2}(g) $$ The hydrogen gas generated is collected over water at \(25.0^{\circ} \mathrm{C}\). The volume of the gas is \(246 \mathrm{~mL}\) measured at 1.00 atm. Calculate the number of grams of sodium used in the reaction. (Vapor pressure of water at \(25^{\circ} \mathrm{C}=0.0313\) atm. \()\)

A certain anesthetic contains 64.9 percent \(\mathrm{C}, 13.5\) percent \(\mathrm{H},\) and 21.6 percent \(\mathrm{O}\) by mass. At \(120^{\circ} \mathrm{C}\) and \(750 \mathrm{mmHg}, 1.00 \mathrm{~L}\) of the gaseous compound weighs \(2.30 \mathrm{~g}\). What is the molecular formula of the compound?

The atmosphere on Mars is composed mainly of carbon dioxide. The surface temperature is \(220 \mathrm{~K}\) and the atmospheric pressure is about \(6.0 \mathrm{mmHg}\). Taking these values as Martian "STP," calculate the molar volume in liters of an ideal gas on Mars.

What does the Maxwell speed distribution curve tell us? Does Maxwell's theory work for a sample of 200 molecules? Explain.
See all solutions

Recommended explanations on Chemistry Textbooks

Inorganic Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Nuclear Chemistry

Read Explanation

Kinetics

Read Explanation

Chemical Reactions

Read Explanation

Organic Chemistry

Read Explanation
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