Lab Quiz #2

Question 1

Absorbance (A)

Answer 1

-log(P/P0) = -log(T) = (molar absorptivity)(path length)(concentration)

Question 2

Concentration (c)

Answer 2

= (absorbtivity)(cm or unit of length) / (absorbance) = ab/A

Question 3

Flow of light through a spectrophotometer

Answer 3

Light source –> lens –> sample cell –> slit –> diffraction grating –> diode array detector

Question 4

Cuvette

Answer 4

Sample container for spectroscopic measurements

Question 5

Absorptivity

Answer 5

A proportionality constant, constant characteristic for a given absorbing species at a specific wavelength

Question 6

Beer’s Law

Answer 6

Relates absorbance to concentration

A = (molar absorptivity)(path length)(concentration)

Question 7

A substance is shown to absorb wavelengths in the 400-500 nm range and the 650-700 nm range. What color is the substance?

Answer 7

Substance must transmit wavelengths in the 500-650 nm range, so it must be green.

Question 8

What temperature is a bunsen burner if its flame is luminous and yellow?

Answer 8

Cool

Question 9

What temperature is a bunsen burner in its pale blue violet outer region?

Answer 9

Moderately hot

Question 10

What temperature is a bunsen burner in its dark blue inner cone?

Answer 10

Extremely hot

Question 11

Bowl shaped porcelainware with a lid

Answer 11

Crucible

Question 12

Bowl shaped porcelainware with a handle and a pouring lip

Answer 12

Casserole

Question 13

Do solid crystalline materials have the exact ratio of atoms predicted by their ideal chemical formulas?

Answer 13

No. The ratio may vary due to defects in the crystal structure

Question 14

Nonstoichiometric solids

Answer 14

Solids whose crystal structures have a ratio of atoms different from the one predicted by their ideal chemical formula

Question 15

What are nonstoichiometric solids also known as?

Answer 15

Berthollides

Question 16

Percent yield formula

Answer 16

(Experimental mass / theoretical mass) times 100