Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 19: Q7P (page 485)

The spreadsheet gives the productεbfor four pure compounds and a mixture at infrared wavelengths. Modify Figure 19-4 to solve four equations and find the concentration of each compound. You can treat the coefficient matrix as if it were molar absorptivity because the path length was constant (but unknown) for all measurements.

Short Answer

Expert verified

The concentration of each compound is,

p-xylene=0.0627Mm-xylene=0.0795Mo-xylene=0.0759Methylbenzene=0.0761M

Step by step solution

01

Define concentration:

In a given quantity of solution, the amount of solute that is present is called concentration.

02

Find the concentration of a compound by using a formula:

Make a spreadsheet,

Hence, the column H can be calculated using the formula,

=MMULTMINVERSEB4:E7;F4:F7

Therefore, the concentration of each compound is,

p-xylene=0.0627Mm-xylene=0.0795Mo-xylene=0.0759Methylbenzene=0.0761M

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

Iodine reacts with mesitylene to form a complex with an absorption maximum at 332 nm in CCl4 solution:

(b)Spectrophotometric data for this reaction are shown in the table.Because[mesitylene]tot>>[I2],we can say that [mesitylene]≈[mesitylene]tot. Prepare a graph ofA/([mesitylene][I2]tot)versusA/[I2]totand find the equilibrium constant and molar absorptivity of the complex.

Scatchard plot for binding of estradiol to albumin. Data in the table come from a student experiment to measure the binding constant of the radioactively labeled hormone estradiol (X)to the protein, bovine serum albumin (P).Estradiol(7.5nM)was equilibrated with various concentrations of albumin for 30minat37°C.A small fraction of unbound estradiol was removed by solid phase microextraction (Section24-4) and measured by liquid scintillation counting. Albumin is present in large excess, so its concentration in any given solution is essentially equal to its initial concentration in that solution. Call the initial concentration of estradiol [X]0and the final concentration of unbound estradiol [X]. Then bound estradiol is[X]0―[X]and the equilibrium constant is

X+P⇌PX   K=[PX][X][P]=[X]0-[X][X][P]

which you can rearrange to
localid="1663648487221" [X]0[X]=K[P]+1

A graph of [X]0/[X]versus [P]should be a straight line with a slope of K.The quotient [X]0/[X]is equal to the counts of radioactive estradiol extracted from a solution without albumin divided by the counts of estradiol extracted from a solution with estradiol. (b) What fraction of estradiol is bound to albumin at the first and last points?

The spreadsheet lists molar absorptivities of three dyes and the absorbance of a mixture of the dyes in a 1.000-cm cell. Use the least-squares procedure in Figure 19-3 to find the concentration of each dye in the mixture.

A study was conducted with derivatives of the DNA nucleotide bases adenine and thymine bound inside micelles () in aqueous solution.

Sodium dodecyl sulfate forms micelles with the hydrocarbon tails pointed inward and ionic headgroups exposed to water. It was hypothesized that the bases would form ahydrogen-bonded complex inside the micelle as they do in DNA:

To test the hypothesis, aliquots of 5.0 mMadenine derivative were mixed with aliquots of 5.0 mMthymine derivative in proportions shown in the table. Each solution also contained 20mMsodium dodecyl sulfate. The concentration of product measured by nuclear magnetic resonance also is shown in the table. Are the results consistent with formation of a 1:1complex? Explain your answer.

This problem can be worked with Equations 19-6 on a calculator or with the spreadsheet in Figure 19-4. Transferrin is the iron-transport protein found in blood. It has a molecular mass of 81 000 and carries twoFe3+ions. Desferrioxamine B is a chelator used to treat patients with iron overload (see the opening of Chapter 12). It has a molecular mass of about 650 and can bind oneFe3+Fe31. Desferrioxamine can take iron from many sites within the body and is excreted (with its iron) through the kidneys. Molar absorptivities of these compounds (saturated with iron) at two wavelengths are given in the table. Both compounds are colorless (no visible absorption) in the absence of iron.


(a) A solution of transferrin exhibits an absorbance of 0.463 at 470 nm in a 1.000-cm cell. Calculate the concentration of transferrin in milligrams per milliliter and the concentration of bound iron in micrograms per milliliter.

(b) After adding desferrioxamine (which dilutes the sample), the absorbance at 470 nm was 0.424, and the absorbance at 428 nm was 0.401. Calculate the fraction of iron in transferrin and the fraction in desferrioxamine. Remember that transferrin binds two iron atoms and desferrioxamine binds only one.
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Reactions

Read Explanation

The Earths Atmosphere

Read Explanation

Physical Chemistry

Read Explanation

Inorganic Chemistry

Read Explanation

Making Measurements

Read Explanation

Nuclear 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