Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 3: Problem 25

Determine the percent, by mass, of the indicated element: (a) \(\mathrm{Pb}\) in tetraethyl lead, \(\mathrm{Pb}\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{4},\) once extensively used as an additive to gasoline to prevent engine knocking (b) Fe in Prussian blue, \(\mathrm{Fe}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]_{3},\) a pigment used in paints and printing inks (c) \(\mathrm{Mg}\) in chlorophyll, \(\mathrm{C}_{55} \mathrm{H}_{72} \mathrm{MgN}_{4} \mathrm{O}_{5},\) the green pigment in plant cells

Short Answer

Expert verified
As these problems are computational in nature, we will need to calculate the values individually. It involves using the atomic weights from the periodic table, and completing several percent composition calculations.

Step by step solution

01

Determine the Molar Mass of the Compounds

Use the atomic masses from the periodic table to determine the molar mass of each compound: (a) Tetraethyl lead, \(\mathrm{Pb}\left(\mathrm{C}_{2}\mathrm{H}_{5}\right)_{4}\)(b) Prussian blue, \(\mathrm{Fe}_{4}[\mathrm{Fe}(\mathrm{CN})_{6}]_{3}\)(c) Chlorophyll, \(\mathrm{C}_{55}\mathrm{H}_{72}\mathrm{MgN}_{4}\mathrm{O}_{5}\)
02

Calculate the Molar Mass of the Indicated Element

Next, calculate the molar mass of the indicated element multyplying the atomic mass of the element by the amount of atoms of the given element instances in the formula:(a) Lead: \(Pb\)(b) Iron: \(Fe\)(c) Magnesium: \(Mg\)
03

Find the Percent Composition

Finally, find the percent composition of the desired element in the compound using the formula:Percent Composition = \((mass \ of \ element/mass \ of \ compound) × 100%\)Substitute the values in for each compound and element and solve for the percent composition.

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

In the year 2000 , the Guinness Book of World Records called ethyl mercaptan, \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{S}\), the smelliest substance known. The average person can detect its presence in air at levels as low as \(9 \times 10^{-4} \mu \mathrm{mol} / \mathrm{m}^{3} .\) Express the limit of detectability of ethyl mercaptan in parts per billion (ppb). (Note: 1 ppb \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{S}\) means there is \(1 \mathrm{g}\) \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{S}\) per billion grams of air.) The density of air is approximately \(1.2 \mathrm{g} / \mathrm{L}\) at room temperature.

Adenine, a component of nucleic acids, has the mass percent composition: \(44.45 \%\) C \(, 3.73 \%\) H, \(51.82 \%\) N. Its molecular mass is 135.14 u. What is its molecular formula?

Three of the following formulas might be either an empirical or a molecular formula. The formula that must be a molecular formula is (a) \(\mathrm{N}_{2} \mathrm{O} ;\) (b) \(\mathrm{N}_{2} \mathrm{H}_{4}\) (c) \(\mathrm{NaCl} ;\) (d) \(\mathrm{NH}_{3}\)

Name the following compounds and specify which ones are best described as ionic: (a) \(\mathrm{OF}_{2} ;\) (b) \(\mathrm{XeF}_{2}\) (c) \(\operatorname{CuSO}_{3} ;\) (d) \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{HPO}_{4}\)

\(\mathrm{MgCl}_{2}\) often occurs in table salt \((\mathrm{NaCl})\) and is responsible for caking of the salt. A 0.5200 g sample of table salt is found to contain \(61.10 \%\) Cl, by mass. What is the \(\% \mathrm{MgCl}_{2}\) in the sample? Why is the precision of this calculation so poor?
See all solutions

Recommended explanations on Chemistry Textbooks

Kinetics

Read Explanation

Making Measurements

Read Explanation

Chemistry Branches

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Nuclear Chemistry

Read Explanation

Chemical Analysis

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