Experiment 2

# Experiment 2 - I =0 Experiment 2 Spectrophotometric...

This preview shows pages 1–2. Sign up to view the full content.

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 and. 2) Show how the value of the Ka for the m-nitroanilium maybe derived from this quantity A = log (I O ÷ I) NB: when Io = 0 it’s when the acid concentration at its highest concentration. This formula is derived from the pKa formula: pka = -log [H + ] [B] [BH + ] 3) Define the quantities and units of “absorbance” and “molar absorption coefficient”. “Absorbance” (A) is described as: A λ = -log 10 (I ÷I O ) I: intensity of light at a particular wavelength ( λ ) that has transmitted light intensity. IO: the initial intensity of light before it enters the sample also known as incident light However, the molar absorption coefficient ( ε ) measures the strength of species to determine its absorption of light at a given wavelength. ε is mainly measured in M -1 cm -1 or LMol -1 cm -1 . 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

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 6

Experiment 2 - I =0 Experiment 2 Spectrophotometric...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online