The primary objective of this experiment is to determine the concentration of an unknown copper (II) sulphate solution. You will be using the colorimeter. In this device, red light from the LED light source will pass through the solution and strike a photocell. The CuSO4 solution used in this experiment has a deep green color. A higher concentration of the colored solution absorbs more light (and transmits less) than a solution of lower concentration. [Content Standard B- Structure and properties of matter] The colorimeter monitors the light received by the photocell as either an absorbance or a percent transmittance value.
Figure 01 picture of colorimeter - (3.imimg.com, 2017)
Beer lambert law:- The absorbance of light …show more content…
Calibration:-
A calibration curve is a mathematical tool used in analytical chemistry that provides a set of reference points that unknown chemical substances can be compared to. When analyzing certain substances, scientists are often unable to get a completely accurate understanding of the substance's makeup. With a calibration curve, chemists can compare known information about unknown substances to make estimates about its makeup and chemical properties.
Aim:-
To use the colorimeter in proper way and observe the absorbance through the colorimeter.
Objective:-
Achieving about how to use the colorimeter.
To examine the relationship between the absorbance and concentration of a copper (II) sulphate solution.
To determine the wavelength (colour) of maximum absorbance for a copper (II) sulphate …show more content…
Discussion:-
Before starting the practical all the equipment which are needed for experiments were properly cleaned. This is done to avoid the contamination and this will increase the accuracy of the result.
During the practical errors can be there due to the reading the meniscus of the pipette and making the solution up to the mark of the volumetric flask. Due to these the concentration of the prepared solution can make any changes. The error in measuring the mass of the CuSO4 and preparation of the solution in the 100cm3 of volumetric flask, pipetting out the solution.
The calibration curve is not going through the zero level because the exact 100ml of 0.4M CuSO4 is prepared for the experiment but during the practical the water level was increase than the 100ml mark in volumetric flask. So, it makes error in the concentration of CuSO4 primary solution.
CuSO4 has ability to absorb water molecules from environment therefore when calculating the mass of CuSO4 it can be an error.
For the distilled water used tap water here.
Conclusion:-
According to the graph the concentration of the unknown solution is found to be a