In Section 6.2d, we saw that pK a of an acid is equal to the pH of the solution at which half the acid has dissociated into its conjugate base. UV–vis spectroscopy can be used to measure the relative concentrations involved if the acid or conjugate base absorbs UV–vis light. With this in mind, suppose that a particular acid has λ max of 312 nm. The given figure shows the absorbance at that wavelength as a function of pH . pK a of the acid is to be determined. Concept introduction: If the given absorbance corresponds to the concentration of acid present, half the absorbance shows the acid which is dissociated in the equal concentration of its conjugate base. pK a of an acid is equal to the pH of the solution at which half the acid has dissociated into its conjugate base.

Question

Want to see the full answer?

Answer 1

Question

Chapter 15, Problem 15.39P

Interpretation Introduction

Interpretation:

In Section 6.2d, we saw that pKa of an acid is equal to the pH of the solution at which half the acid has dissociated into its conjugate base. UV–vis spectroscopy can be used to measure the relative concentrations involved if the acid or conjugate base absorbs UV–vis light. With this in mind, suppose that a particular acid has λmax of 312 nm. The given figure shows the absorbance at that wavelength as a function of pH. pKa of the acid is to be determined.

Concept introduction:

If the given absorbance corresponds to the concentration of acid present, half the absorbance shows the acid which is dissociated in the equal concentration of its conjugate base. pKa of an acid is equal to the pH of the solution at which half the acid has dissociated into its conjugate base.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

LTS Solid: AT=Te-Ti Trial 1 Trial 2 Trial 3 Average ΔΗ Mass water, g 24.096 23.976 23.975 Moles of solid, mol 0.01763 001767 0101781 Temp. change, °C 2.9°C 11700 2.0°C Heat of reaction, J -292.37J -170.473 -193.26J AH, kJ/mole 16.58K 9.647 kJ 10.85 kr 16.58K59.64701 KJ mol 12.35k Minimum AS, J/mol K 41.582 mol-k Remember: q = mCsAT (m = mass of water, Cs=4.184J/g°C) & qsin =-qrxn & Show your calculations for: AH in J and then in kJ/mole for Trial 1: qa (24.0969)(4.1845/g) (-2.9°C)=-292.37J qsin = qrxn = 292.35 292.37J AH in J = 292.375 0.2923kJ 0.01763m01 =1.65×107 AH in kJ/mol = = 16.58K 0.01763mol mol qrx Minimum AS in J/mol K (Hint: use the average initial temperature of the three trials, con Kelvin.) AS=AHIT (1.65×10(9.64×103) + (1.0 Jimai

For the compound: C8H17NO2 Use the following information to come up with a plausible structure: 8 This compound has "carboxylic acid amide" and ether functional groups. The peaks at 1.2ppm are two signals that are overlapping one another. One of the two signals is a doublet that represents 6 hydrogens; the other signal is a quartet that represents 3 hydrogens.

Vnk the elements or compounds in the table below in decreasing order of their boiling points. That is, choose 1 next to the substance with the highest bolling point, choose 2 next to the substance with the next highest boiling point, and so on. substance C D chemical symbol, chemical formula or Lewis structure. CH,-N-CH, CH, H H 10: H C-C-H H H H Cale H 10: H-C-C-N-CH, Bri CH, boiling point (C) Сен (C) B (Choose