Login Registrieren

Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

Chapter 18: Q19P (page 457)

If a sample for spectrophotometric analysis is placed in a 10 - cmcell, the absorbance will be 10times greater than the absorbance in a 1 - cmcell. Will the absorbance of the reagent-blank solution also be increased by a factor of 10?

Short Answer

Expert verified

Yes, the absorbance of the reagent-blank solution also be increased by a factor of 10.

Step by step solution

01

Define Reagent Blank Solution

A reagent blank is a mixture of any solvent and reagent that would be presented to the detector for analysis of a test sample and is analysed to determine if it contributes to the measurement signal.

02

Reaction of Solution

Yes, the absorbance of the reagent-blank solution also be increased by a factor of 10.

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

Nitrite ion ${NO}^{-}_{2}$ , is a preservative for bacon and other foods, but it is potentially carcinogenic. A spectrophotometric determination of ${NO}^{-}_{2}$ makes use of the following reactions

Here is an abbreviated procedure for the

determination:

1. To 50.0ml of unknown solution containing nitrite is added 1.00mL of sulfanilic acid solution.

2. After 10min , 2.00mL of 1 –a minonaphthalene solution and 1.00 mL of buffer are added.

3. After 15 min, the absorbance is read at 520 nm in a 5.00-cm cell.

The following solutions were analyzed:

A. 50.0 mL of food extract known to contain no nitrite (that is, a negligible amount); final absorbance =0.153.

B. 50.0mL of food extract suspected of containing nitrite; final absorbance $= 0.622$ .

C. Same as B, but with $10 .0 μ L of 7 .50 \times 10^{- 3} {MNaNO}_{2}$ added to the 50.0-mL sample; final absorbance =0.967.

(a) Calculate the molar absorptivity, of the colored product. Remember that a $5.00$ -cm cell was used.

(b) How many micrograms of ${NO}^{-}_{2}$ were present in 50.0mL of food extract?

Preparing standards for a calibration curve.

(a) How much ferrous ammonium sulfate $(Fe {({NH}_{4})}_{2} {({SO}_{4})}_{2} \cdot 6 H_{2} OFM 392 .15)$ should be dissolved in a 500mL volumetric flask withto obtain a stock solution with $1000 μ gFe / mL$ ?

(b) When making stock solution (a), you weighed out 3.627 g of reagent. What is the Fe concentration in?

(c) How would you prepare 250mL of standard containing containing $~ 1, 2, 3, 4, 5, 6, 7, 8 and 10 in 0.1 {MH}_{2} {SO}_{4}$ infrom stock solution (b) using only 5- and 10-mL Class A pipets, only 250mL volumetric flasks, and only two consecutive dilutions of the stock solution? For example, to prepare a solution with $~ 4 μ gFe / mL,$ , you could first dilute 15mL(=10+5mL) of stock solution up to 250 mL $mL to get ~ (\frac{15}{25}) (1000 μ gFFe / mL) =\sim 60 μ gFe / mL$ Then dilute 15mL of the new solution up to 250 mL again to get $~ (\frac{15}{250}) (60 μ gFe / mL) =\sim 3 .6 μ gFe / mL$

18-7: How do transmittance, absorbance, and molar absorptivity differ? Which one is proportional to concentration?

18-6. Box 3-1 showed a single-beam spectrophotometric ozone monitor. The emission spectrum of the mercury vapor lamp is shown in Box 18-2.

What is the light source?
What is the detector?
What is the monochromator?
What are the components of the optical pathlength, b?
How does this instrument measure O3?

18-29. Biotin-streptavidin fluorescence titration. Biotin is a cofactor in enzymatic carboxylation reactions. Biotin activates ${CO}_{2}$ for biosynthetic reactions.

Streptavidin is a protein isolated from the bacterium Streptomyces avidinii that binds biotin with a formation constant of $~ 10^{14} M^{- 1}$ . The biotin-streptavidin complex is widely used in biotechnology because the noncovalent complex is stable in the presence of detergents, protein denaturants, and organic solvents, and at extremes of pH and temperature.

The stoichiometry of the biotin-streptavidin complex was measured by a fluorescence titration. Fluorescein (page 453 ) covalently attached to biotin via the biotin carboxyl group fluoresces at 520 nm when irradiated at 493 nm. When biotin-fluorescein (BF) binds to streptavidin (SA), fluorescence decreases. The table gives emission intensity for addition of BF to SA and also for addition of SA to BF. Data are already corrected for dilution.

(a) Make a graph of fluorescence versus mole ratio for each titration and state the stoichiometry of binding of biotin to streptavidin.

(b) Explain the shape of each titration curve.

See all solutions

Recommended explanations on Chemistry Textbooks

Physical Chemistry

Read Explanation

Chemistry Branches

Read Explanation

Chemical Reactions

Read Explanation

Organic Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Making Measurements

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