QUESTION 1 A standard solution has a %T of 81.7. An unknown solution has a %T of

Question

QUESTION 1 A standard solution has a %T of 81.7. An unknown solution has a %T of 24.1. Is the concentration of the unknown higher, lower, or the same as the concentration of the standard? O Higher Same O Lower QUESTION 2 1 points Save A A standard solution has an absorbance of .435. An unknown solution has an absorbance of .619. Is the concentration of the unknown higher, lower, or the same as the concentration of the standard? O Higher O Same O Lower QUESTION 3 1 points Save You weigh out 0.1342 g of copper wire (AW 63.546), dissolve it in excess nitric acid, and dilute to volume in a 100mL volumetric flask with distilled water What is the concentration of the resulting solution?

Explanation / Answer

Change to Absorbance

A = 2-log(T%)

A1 = 2-log(81.7) = 0.0877

A2 = 2-log(24.1) = 0.6179

since A increases, then

recall that

Beer's law

A = e*l*C

A = absorbance of sample

e is the molar absorptivity , the typical units are 1/M-cm

l size of cuvette, typically reported in cm

c is the molar concentration, in mol per ltier or M

Therefore

if A increases, Concentration must increase

it will be higher

Q2.

if A2 > A1

then this must be HIGHER

Q3

mol of copper = mass/MW = 0.1342/63.546

mol of Cu = 0.002113

[Cu] = mol/V = 0.002113/0.1 L = 0.02113 M

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.