If you use the lmax during the calibration plot (Beer's plot) and then change to some other wavelength for the measurement of the sample, how will this affect x?
x is the moles of H20 in the equation
I echo Bob Pursley's comment. I have no idea. What experiment are you doing? What does H2O have to do with it? What equation?
To understand how changing the wavelength for the measurement of the sample affects x (the moles of H2O), we need to explore the concept of a calibration plot and how it relates to the measurement process.
The calibration plot, also known as Beer's plot, is a graphical representation of the relationship between the concentration of a substance and its absorbance under a specific wavelength. By measuring the absorbance of known concentration samples, we can create a calibration curve, which allows us to determine the concentration of unknown samples.
In this context, the "lmax" parameter refers to the wavelength at which the absorbance is maximum for the substance of interest. Now, let's examine how changing this wavelength may affect the determination of x:
1. Calibration Plot: The initial step in creating a calibration plot is to measure the absorbance of solutions with known concentrations of the target substance at the predetermined wavelength (lmax). By plotting the absorbance versus concentration, we can obtain a linear relationship.
2. Determination of x: Once the calibration plot is established, we can use it to determine the concentration (and subsequently the moles) of the target substance in unknown samples. This involves measuring the absorbance of the unknown sample at the same wavelength used during the calibration.
If you change the wavelength for measuring the sample from lmax to another value, it could potentially lead to inaccuracies in determining x for the following reasons:
a. Different Molar Absorptivity (ε): The molar absorptivity is a constant that relates the concentration of the substance and its absorbance at a specific wavelength. Changing the wavelength means that the molar absorptivity value used in the calibration plot may not be appropriate for the new wavelength, which can result in misleading concentration calculations.
b. Overlapping Absorption Peaks: Some substances exhibit absorption peaks at multiple wavelengths, and sometimes these peaks can overlap. If the new wavelength chosen for measurement coincides with an overlapping peak, it can lead to interference from other substances, affecting the accuracy of the analysis.
c. Deviation from Linearity: The calibration curve obtained from the calibration plot assumes a linear relationship between absorbance and concentration. Changing the wavelength may result in non-linear behavior, meaning the relationship can no longer be assumed as linear. This can introduce errors when determining x.
In conclusion, changing the wavelength used for measurement from the lmax used in the calibration plot can potentially affect the determination of x. It is crucial to consider the specific characteristics of the substance being analyzed, potential interference from other substances, and the linearity of the calibration plot under the new wavelength. To maintain accuracy, it is generally recommended to measure the absorbance of the sample at the same wavelength used in the calibration plot.