CAN YOU HELP ME Determine the copper (II) sulfate concentrations in your two unk

Question

CAN YOU HELP ME Determine the copper (II) sulfate concentrations in your two unknown samples from the calibration plot.

AND

Were the unknown solutions more or less concentrated than the copper (II) sulfate solution used in experiment 1?

exp 2.

Concentration of Cu2+ at cuvette 1:           0.06 *4 = x * 10

or, x = 0.024 M

Concentration of Cu2+ at cuvette 2:           0.06 *7 = x * 10

x = 0.042 M

Concentration of Cu2+ at cuvette 3:          0.06 M

measure absorbance of the three copper solutions at 700 nm.

Now draw a plot of ' absorbance vs concentration' .

According to the Beer's law ( A = cl), graph of 'A vs c') will be a linear one.

exp 3.

From the above graph, you can calculate the concentration of the unknown copper solution.

Measure the absorbance of the unknown solution. Find the corresponding concentration of the absorbance from the graph, the concentration is the 'concentration of the unknown solution'.

Explanation / Answer

According to Beer Lambert's law

Absrobance = Concentration X path length X absroptivity

So if we plot a graph between absrobance and concentration, we will obtain a straight line with

Slope = Path length x absroptivity

the equation will be

y =mx + c

x = concentration

y = absrobance

Now if we know the linear equation of the given graph we can substitute the value of absrobance of unkown and can determine its concentration

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