Just need help answering the ***** question under conclusions. here is my worksh
ID: 538120 • Letter: J
Question
Just need help answering the ***** question under conclusions. here is my worksheet with information
Record your absorbance measurements for the copper (II) sulfate solution in the table below.
Record your absorbance measurements for the cobalt (II) chloride solution in the table below.
Data Analysis
Experiment 2: Measure Absorbance versus Concentration for Cu+2 Ions
Lab Results
What wavelength did you use to measure the absorbance of the copper (II) sulfate solutions?
700 nm
Data Analysis
The y-intercept of the plot of absorbance versus concentration is approximately 0. Why is this?
It should be a straight line obtained by having a slope of = 1 and y-intercept = 0.
Experiment 3: Determine the Cu+2 Concentration in Unknown Solutions of Copper (II) Sulfate
Lab Results
How many mL of the unknown solutions did you use for your absorbance measurements?
10 mL
Data Analysis
Determine the copper (II) sulfate concentrations in your two unknown samples from the calibration plot.
wavelength used: 700 nm
absorbance unknown: a. 0.08 b. 0.12
Conclusions
*******Were the unknown solutions more or less concentrated than the copper (II) sulfate solution used in experiment 1?
Given the data in the table below, what is the concentration of the unknown solution? Both solutions contain the same substance.
0.63 M is the concentration of the unknown solution.
Wavelength (nm) Absorbance 400 0.00 nm 420 0.00 nm 440 0.00 nm 460 0.00 nm 480 0.00 nm 500 0.00 nm 520 0.00 nm 540 0.00 nm 560 0.02 nm 580 0.05 nm 600 0.09 nm 620 0.14 nm 640 0.22 nm 660 0.35 nm 680 0.50 nm 700 0.63 nmExplanation / Answer
From the given data,
Wavelength used for measurement of absorbance of solution,
700 nm
At 700 nm, we obtained highest absorbance value and thus is lambda-max for the solution
Concentration of solution from absorbance,
when absorbance = 0.08
concentration = 1.25 x 0.08/0.75 = 0.13 M
when absorbance = 0.12
concentration = 1.25 x 0.12/0.75 = 0.20 M
The unknown solutions were less concentrated than the copper (II) solutions used for the given experiment.
Given the data in the table below, the concentration of the unknown solution having both solutions the same compound in it,
concentration of unknown solution = 1.25 x 0.38/0.75
= 0.63 M
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