Experiment 3 - Experiment 2: Spectrophotometric...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Experiment 2: Spectrophotometric Determination of Acidity Constant “A” Questions 1) What quantity is the spectrophotometric analysis measuring? A spectrophotometer measures the intensity of light as a function of the wavelength of light. The spectrophotometer measures the absorbance (A) by measuring the amount of light absorbed when the light is shined through the sample. 2) Show how the value of the Ka for the m-nitroaniline maybe derived from this quantity A = log (I O ÷ I) pka = -log [H + ] [B] [BH + ] 3) Define the quantities and units of “absorbance” and “molar absorption coefficient”. 4) A solution containing 4.48ppm KMnO 4 has a transmittance of 0.309 in 1.00cm cell at 520nm. Calculate the molar absorption coefficient of KMnO 4 . At wt of KMnO4 = 158.036 158.036 × 100 = 158036ppm Therefore 1M of KMnO 4 is 158036ppm If 1M → 158036ppm Then 4M → xppm 4.48ppm = 2.834797 × 10 -5 M Now A = -log 10 T = εCl = -log 10 (0.309)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
= 0.51004152 Therefore εCl = 0.51004152 ε =
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

Experiment 3 - Experiment 2: Spectrophotometric...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online