Laboratory Techniques in Organic Chemistry
Laboratory Techniques in Organic Chemistry
4th Edition
ISBN: 9781464134227
Author: Jerry R. Mohrig, David Alberg, Gretchen Hofmeister, Paul F. Schatz, Christina Noring Hammond
Publisher: W. H. Freeman
Question
Book Icon
Chapter 13, Problem 1Q
Interpretation Introduction

Interpretation:

The refractive index for a compound at 25°C is to be determined when the refractive index of the compound at 20.1°C is 1.3191.

Concept introduction:

Refractive index is an important physical property that determines the composition of the substance. It determines the amount of refraction the light undergoes due to the change in speed because of the difference in densities.

Refractive index (n) is defined as the ratio of the velocity of light in vacuum or air to the velocity of light in another medium of the substance under study that is given as follows:

  n=Vair/vacuumVanothermediumunderstudy

Where,

  • Vair/vacuum is the velocity of light in vacuum or air.
  • Vanothermediumunderstudy is the velocity of light in another medium of the substance under study.

The density of organic compounds varies with temperature so does velocity of light passing through it. Density is inversely proportional to the temperature of the substance.

To determine the refractive index an instrument called refractometer is used.

The formula to calculate the variation of refractive index with temperature is given as follows:

  Δn=4.5×104×(T1T2)

Where,

  • Δnis the change in the refractive index.
  • T1 and T2 is the initial and final temperature, respectively.

Expert Solution & Answer
Check Mark

Answer to Problem 1Q

The refractive index for the compound at 25°C is 1.3168.

Explanation of Solution

Given Information:

The refractive index for the compound at 20°C is 1.3191.

The formula to calculate the variation of refractive index with temperature is given as follows:

  Δn=4.5×104×(T1T2)

The value of T1 is 20.1°C .

The value of T2 is 25°C .

Substitute the values in the above formula to calculate the variation of refractive index with temperature.

  Δn=4.5×104×(T1T2)=4.5×104(20.1°C25°C)=0.002205

The formula to calculate the refractive index at 25°C is given as follows:

  Δn=n2n1 ....... (1)

Where,

  • n2 is the refractive index at 25°C .
  • n1 is the refractive index at 20.1°C .

Rearrange the equation (1) to calculate the value of the refractive index (n2) at 25°C. We get,

  n2=Δn+n1

The value of Δn is 0.002205.

The value of n1 is 1.3191.

Substitute the values in the above formula to calculate the refractive index ( n2 ) at 25°C .

  n2=n1+Δn=1.3191+(0.002205)=1.3168

Conclusion

The refractive index for the compound at 25°C is 1.3168.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
(a 4 shows scanning electron microscope (SEM) images of extruded actions of packing bed for two capillary columns of different diameters, al 750 (bottom image) and b) 30-μm-i.d. Both columns are packed with the same stationary phase, spherical particles with 1-um diameter. A) When the columns were prepared, the figure shows that the column with the larger diameter has more packing irregularities. Explain this observation. B) Predict what affect this should have on band broadening and discuss your prediction using the van Deemter terms. C) Does this figure support your explanations in application question 33? Explain why or why not and make any changes in your answers in light of this figure. Figure 4 SEM images of sections of packed columns for a) 750 and b) 30-um-i.d. capillary columns.³
fcrip = ↓ bandwidth Il temp 32. What impact (increase, decrease, or no change) does each of the following conditions have on the individual components of the van Deemter equation and consequently, band broadening? Increase temperature Longer column Using a gas mobile phase instead of liquid Smaller particle stationary phase Multiple Paths Diffusion Mass Transfer
34. Figure 3 shows Van Deemter plots for a solute molecule using different column inner diameters (i.d.). A) Predict whether decreasing the column inner diameters increase or decrease bandwidth. B) Predict which van Deemter equation coefficient (A, B, or C) has the greatest effect on increasing or decreasing bandwidth as a function of i.d. and justify your answer. Figure 3 Van Deemter plots for hydroquinone using different column inner diameters (i.d. in μm). The data was obtained from liquid chromatography experiments using fused-silica capillary columns packed with 1.0-μm particles. 35 20 H(um) 큰 20 15 90 0+ 1500 100 75 550 01 02 594 05 μ(cm/sec) 30 15 10

Chapter 13 Solutions

Laboratory Techniques in Organic Chemistry

Knowledge Booster
Background pattern image
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Chemistry
Chemistry
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning
Text book image
Chemistry
Chemistry
ISBN:9781259911156
Author:Raymond Chang Dr., Jason Overby Professor
Publisher:McGraw-Hill Education
Text book image
Principles of Instrumental Analysis
Chemistry
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Cengage Learning
Text book image
Organic Chemistry
Chemistry
ISBN:9780078021558
Author:Janice Gorzynski Smith Dr.
Publisher:McGraw-Hill Education
Text book image
Chemistry: Principles and Reactions
Chemistry
ISBN:9781305079373
Author:William L. Masterton, Cecile N. Hurley
Publisher:Cengage Learning
Text book image
Elementary Principles of Chemical Processes, Bind...
Chemistry
ISBN:9781118431221
Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:WILEY