# science(chem)

If I have a graph of concentration in Absorbance at 400nm vs [micromolar]of para-nitrophenol

The slope would be the extinction coefficient. (y=mx) if forced through 0
The problem is what is y?
I know y is the absorbance but it's given on a paper i have as, y= Absorbance at lmax

Can someone explain what lmax means?
I need to find the concentration of an unknown from this standard curve and I think I find it by first finding the epsilon from the graph, by using..

1. y=mx then:
m= # microM^-1 cm^-1
(not sure if it needs to be in M^-1 or how to convert it to that if I need it to be)
The m is the epsilon.
The problem is that the graph's slope is 0.003653 is molar absorption coefficient supposed to be that small?

2. then I take that and use it to find the concentration of the unknown solution, from beer's law, since I have the absorption of it.
Another issue is that the sample I did measure, was of a solution that I diluted in a ration of 1ml sample to 3ml pH10 buffer. The standard curve sample of 0.1M Paranitrophenol was also diluted with buffer prior to being analyzed, with same ratio of dilution.
First, finding the concentration of the diluted unknown is okay, as long as the absorption coefficient is right...by using A= ebc
A= known
e= calculated from graph above
c= concentration (can be found)
b= 1cm

But how am I to find the original concentration of the unknown stock paranitrophenol if I did not analyze it and was not told to....instruction ssay to, "calculate the concentration of the diluted unknown Paranitrophenol and the original unknown stock paranitrophenol using the standard curve generated"

1. 👍 0
2. 👎 0
3. 👁 95

## Similar Questions

1. ### chemistry

why ortho nitrophenol are more volatile than para nitrophenol

asked by Paul on May 14, 2008
2. ### Chemistry Help

If a graph is given for a cuvette using a 1.00 cm , predict the graph if a 2.0 cm diameter test tube and a 0.50cm test tube are used. The points for the 1.00cm test tube are (0,0),((2E-5),0.1), ((4E-5),0.2), ((6E-5),0.4),

asked by Zara on November 16, 2007
3. ### chemistry

An unknown was prepared with the concentration of 0.000331 M. A Beer's Law plot was prepared using the absorbance values from standard solutions of ASA and a line drawn through all the points passed through the origin with a slope

asked by jared on May 14, 2007
4. ### DRBOB

okay you talked about using a graph and we made one so this is the formula from it. y = 2.2019x y = absorbance x= concentration so if i have an absorbance of .02, do i do... .02/2.2019= .0091 .0091 would be x so it would be the

asked by jaseline on March 11, 2009
5. ### Chemistry

The spectrophometer was used to measure the absorbance of each of a series of [FeSa]+ solutions. A standard curve was construnceted by plotting the absorbance vs. concentration (M). The slope and y-intercept were found to be 1496

asked by Erin on April 2, 2017
6. ### Chem

If you have an equation for a line, y = 0.15x + 0.010, where y is absorbance and x is concentration in molarity of Fe (2+), calculate the concentration of a test sample with an absorbance of 0.065. What is the absorbance value for

asked by Ch on November 15, 2016
7. ### chemistry

The standard solution of FeSCN2+ (prepared by combining 9.00 mL of 0.200 M Fe(NO3)3 w/1.00 mL of 0.0020 M KSCN) has an absorbance of 0.510. If a trial's absorbance is measured to be 0.250 and its initial concentration of SCNâ€“

asked by Jason on April 9, 2008
8. ### Organic Chemistry

Assuming you have a mixture of 2-nitrophenol and 4-nitrophenol, which solvent would be most suitable for recrystallization if you want to isolate 4-nitrophenol? Water Diethyl ether Toluene Acetone Ethanol

asked by Maria on April 29, 2010
9. ### chemistry

An unknown was prepared with the concentration of 0.000630 M. A Beer's Law plot was prepared using the absorbance values from standard solutions of ASA and a line drawn through all the points passed through the origin with a slope

asked by john on January 27, 2008
10. ### chemistry

An unknown was prepared with the concentration of 0.000630 M. A Beer's Law plot was prepared using the absorbance values from standard solutions of ASA and a line drawn through all the points passed through the origin with a slope

asked by Michael on January 27, 2008

More Similar Questions