An experiment was performed under identical conditions as yours. The absorbance of the penny solution was recorded as 0.219 absorbance units. A calibration plot of absorbance vs. concentration of Cu(II) (M) yielded the following trendline equation: y= 11.589x - 0.0002

Required:
What is the concentration (mol/L) of the penny solution?

Concentration C = 0.0189 mol/L

Explanation:

From the given information:

Let consider the formula used in calculating the concentration according to Beer's law:

--- (1)

here;

A = absorbance

ε = coefficient of molar absorptivity

L = path length

C = concentration (mol/L)

Also, from Beer law plot:

y = mx+b

where,

y represent absorbance A

b represents intercept

m represents the coefficient of molar absorptivity ε

and x represents the concentration(C).

replacing the substituted entities

A = ε × C + b ---- (2)

Making the concentration the subject of the above formula:

----(3)

From y = 11.589x - 0.0002

A = 11.589 *C - 0.0002

Given that:

A = 0.219

∴

0.219 = 11.589 *C - 0.0002

0.219 + 0.0002 =  11.589 *C

C = 0.2192/11.589

C = 0.0189 mol/L

samuel de champlain. in 1608, king henry iv sponsored pierre dugua, sieur de mons and samuel de champlain as founders of the city of quebec with 28 men. this was the second permanent french settlement in the colony of canada.