A lab experiment to determine the concentration of an unknown solution by colorimetry

The absolute effect of the factors A, B, and C can be calculated as follows:

A lab experiment to determine the concentration of an unknown solution by colorimetry

Colorimetry measures the absorption of light at wavelengths within the visible region of the electromagnetic spectrum.

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It can be used to identify the unknown concentration of a solution in reference to a solution of a known concentration. When a solution appears coloured, you see the colour that has not been absorbed by the molecules.

A light beam is passed through a sample inserted into a colorimeter, the light is split into two beams, one being absorbed by the sample, the other beam will pass through to a photocell which measure the amount of light absorbed.

This figure is not measured in any unit but is an indication of the amount of light absorbed when referenced against other samples. Equipment Potassium Manganate ?

Part 1 — Determination of an Absorption Spectrum An absorption spectrum will be created by measuring a sample of Potassium Manganate ? The absorption spectrum will show how much light is absorbed at each wavelength. Results Wavelength nm Absorption 0. The standard solutions will be tested at the wavelength of maximum absorption as this wavelength would be the most sensitive to absorbance changes.

As the amount of light absorbed is directly related to the concentration of the solution, the results can be used to determine the concentration of the unknown solution.

Zero concentration is a measurement of the absorption of distilled water. Results x 0. Testing the sample more than once will ensure that the absorption is an accurate result. The unknown solution will be plotted against the calibration curve using the mean average. This will determine the concentration of the solution.

When the 20ppm solution was tested against nm, an absorption reading of 0. Unknown Z also gave a reading of 0. This could mean that Unknown Z has a concentration of 20ppm and that some areas of the experiment were flawed. Some of the methods used during this experiment were not completely accurate.

The biggest source in inaccuracy was during making the standard solutions.

When a sample of one solution was transferred by pipette into a cuvette, trace amounts would have been left in the pipette meaning that when the same pipette was used for the next strength solution, the contents were either too diluted or too strong.

When making up the standard solutions a burette was used this is also an inaccurate way of measuring liquids. Either too much or too little solution and distilled water went into the mixture meaning that the standard solutions were not accurate.

As the standard solutions were not accurate, the calibration curve will not be exact so when the Unknown Z has been plotted against the curve it will not be against the correct concentration but will be close enough to be given an approximate concentration Other areas of error include not wiping finger prints off of the cuvettes before they were inserted into the colorimeter which would interfere with the absorption of light.

In part 1 of the experiment, the colorimeter gave a reading of 2. This reading is the maximum absorption that the colorimeter could display shown by the colorimeter display flashing. The reading would suggest that the maximum amount of light possible was absorbed.

This does not seem likely as when all light is absorbed, the colour you see is black whereas potassium manganite is coloured purple.

Using a colorimeter with a larger range of displays may give more accurate readings of the absorption. This would not change the wavelength of maximum absorption. Evaluation If this experiment was to be repeated, the absorption of the ?

This would make the experiment as a whole more accurate as the mean average could be used to plot the graph which will be more indicative of the true absorption.

A lab experiment to determine the concentration of an unknown solution by colorimetry

Using a measuring cylinder instead of pipettes and burettes would also aid the experiment in being more accurate.Determining the Concentration of a Solution: Beer’s Law Advanced Chemistry with Vernier 17 - 3 7. Determine the optimal wavelength for creating this standard curve.

a. Remove the blank cuvette, and place the M standard into the cuvette slot. b. Click. The absorbance vs. wavelength spectrum will be displayed.

A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols and numbers. Introduction. In this chapter the actual execution of the jobs for which the laboratory is intended, is dealt with. The most important part of this work is of course the analytical procedures meticulously performed according to the corresponding SOPs. Experiment involving titrimetric procedures Estimation of ascorbic acid by titrimetric method using 2, 6 – dichlorphenol indophenol. Determination of .

Click. c. Prospective inbound mobility students can browse through the list of undergraduate courses available at UTM for the UTM Student Exchange Program below. The primary objective of this experiment is to determine the concentration of an unknown nickel (II) sulfate solution.

You will be using the Colorimeter shown in Figure 1. L. McAfoos G. Brooks Period 9 – AP Chemistry September 13, Beer’s Law Lab Abstract: An experiment was done to determine the concentration of a solution of nickel II sulfate (NiSO 4) using Beer’s Law, which states that the absorbance of a solution is directly proportional to .

The Colormaking Attributes.A standard, unambiguous language for visual color description is an innovation of 19th century color scientists. And the foundation of this color language is the idea of a "color container" or color space.. 2. In chemistry, spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength.

It is more specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with visible light, near-ultraviolet, and near-infrared, but does not cover time-resolved .

CH Lesson 4 Colorimetry