Week 4: Polarimetry

Question 1

What is polarimetry?

Answer 1

Polarimetry is the measurement of the polarization of light.

Question 2

True or False: Polarimetry can be used to determine the concentration of chiral compounds.

Answer 2

True

Question 3

Fill in the blank: The instrument used to measure the angle of rotation of polarized light is called a __________.

Answer 3

polarimeter

Question 4

What is the significance of optical activity in polarimetry?

Answer 4

Optical activity refers to the ability of chiral substances to rotate the plane of polarized light.

Question 5

Which type of light is used in polarimetry?

Answer 5

Monochromatic light

Question 6

What is the unit of measurement for optical rotation?

Answer 6

Degrees

Question 7

True or False: Both enantiomers of a chiral compound rotate polarized light in the same direction.

Answer 7

False

Question 8

What does a polarimeter measure?

Answer 8

A polarimeter measures the angle of rotation of polarized light as it passes through a sample.

Question 9

Multiple Choice: Which of the following substances is typically analyzed using polarimetry? A) Water B) Sugar C) Salt D) Oil

Answer 9

B) Sugar

Question 10

What is the relationship between concentration and optical rotation in polarimetry?

Answer 10

The optical rotation is directly proportional to the concentration of the chiral substance.

Question 11

Fill in the blank: The __________ of a substance is defined as the specific rotation divided by the concentration.

Answer 11

optical purity

Question 12

True or False: Polarimetry can only be used for liquid samples.

Answer 12

False

Question 13

What type of molecules are primarily studied using polarimetry?

Answer 13

Chiral molecules

Question 14

What is specific rotation?

Answer 14

Specific rotation is the observed rotation of light divided by the path length and concentration of the solution.

Question 15

Multiple Choice: The specific rotation of a compound is influenced by: A) Temperature B) Wavelength of light C) Concentration D) All of the above

Answer 15

D) All of the above

Question 16

What is the role of a polarizer in a polarimeter?

Answer 16

A polarizer allows only light waves of a specific polarization to pass through.

Question 17

True or False: The plane of polarized light can be rotated by passing it through a non-chiral substance.

Answer 17

False

Question 18

What is the maximum angle of rotation for a solution in polarimetry?

Answer 18

The maximum angle of rotation depends on the specific compound and its concentration.

Question 19

Fill in the blank: The __________ is the angle at which the light is rotated when it exits the sample tube.

Answer 19

exit angle

Question 20

What does a negative optical rotation indicate?

Answer 20

A negative optical rotation indicates that the substance rotates polarized light in the opposite direction.

Question 21

Multiple Choice: Which of the following can affect the results of polarimetry? A) Sample impurities B) Temperature variations C) Light wavelength D) All of the above

Answer 21

D) All of the above

Question 22

What is the purpose of a compensator in polarimetry?

Answer 22

A compensator is used to enhance the sensitivity of the measurement by compensating for the optical rotation.

Question 23

True or False: The principle of polarimetry is based on the interaction of light with matter.

Answer 23

True

Question 24

What is the main advantage of using polarimetry in analytical chemistry?

Answer 24

Polarimetry is a non-destructive method that can provide information about chiral purity and concentration.