Lab Deck (Final Exam)

Question 1

Accuracy vs. Precision?

Answer 1

Accuracy: closeness of a value to its true value

Precision: closeness of measurements to each other

Question 2

What is the Scott Reagent used for?

Answer 2

Detecting cocaine

Question 3

What is the Marquis Reagent used for?

Answer 3

Detecting meth

Question 4

Are color tests presumptive or confirmative?

Answer 4

Presumptive

Question 5

What results do color tests give?

Answer 5

Positive or negative

Question 6

What are the 3 factors affecting the probability of drugs on currency?

Answer 6

1) Age
2) Denomination
3) Location of circulation

Question 7

What does the R(f) in R(f) value stand for?

Answer 7

Retention (retardation) factor

Question 8

R(f) is the ratio of…

Answer 8

Analyte distance travelled to distance solvent front travelled

Question 9

What is the mechanism of action for paper chromatography?

Answer 9

Nonpolar solvent moves up along polar cellulose in paper via capillary action

Question 10

Method of separating mixtures into their components based on physical and/or chemical properties of the components

Answer 10

What is chromatography?

Question 11

What is the stationary phase in paper chromatography?

Answer 11

Paper (polar cellulose)

Question 12

What is the mobile phase in paper chromatography?

Answer 12

Nonpolar solvent

Question 13

Physical property of matter relating the mass of an object to its volume.

Answer 13

What is density?

Question 14

When a substance floats…

Answer 14

Less dense than medium

Question 15

When a substance sinks…

Answer 15

More dense than medium

Question 16

When a substance suspends…

Answer 16

Same density as medium

Question 17

An object immersed in fluid displaces a volume of fluid equal to its value.

Answer 17

What is water displacement, or Archimedes principle?

Question 18

Comparative method stating that a solid particle will float in a liquid medium of greater density, sink in a liquid of lower density, or remain suspended in a liquid of equal density

Answer 18

What is flotation?

Question 19

Refractive index is the ratio of…

Answer 19

Speed of light in vacuum to speed of light in medium

Question 20

True or False: RI will always be greater than 1.

Answer 20

True

Question 21

If the Becke Line is inside the glass chip, then the RI of the chip is { } than the RI of the surrounding medium.

Answer 21

Greater

Question 22

What does FTIR stand for?

Answer 22

Fourier-Transform Infrared Spectroscopy

Question 23

What causes spectral peaks in FTIR?

Answer 23

Functional groups

Question 24

What is the model of the FTIR machine used?

Answer 24

Perkin-Elmer Spectrum 100 FT-IR Spectrometer

Question 25

What are the 7 main parts of the GC-MS?

Answer 25

1) Injector port 2) Oven 3) Hydrogen gas 4) Column 5) Interface (connects GC to MS) 6) Ion source 7) Bulb

Question 26

What do the peaks on a mass spectrum represent?

Answer 26

Fragment ions of varying relative abundance

Question 27

What is the model of the GC-MS used?

Answer 27

Perkin-Elmer Clarus 600 GC + MS

Question 28

What does m/z mean?

Answer 28

Mass-to-charge ratio

Question 29

What is the name of a GC graph?

Answer 29

Gas chromatogram

Question 30

What is the model of the UV-Vis spectrometer used?

Answer 30

Perkin-Elmer Lambda 35 UV-Vis Spectrometer

Question 31

What is UV-Vis used for?

Answer 31

Quantitative measurements (e.g. concentration) when the type of compound to be analyzed is known

Question 32

Shift to a longer wavelength.

Answer 32

What is red shift?

Question 33

Shift to a shorter wavelength.

Answer 33

What is blue shift?

Question 34

Why are quartz cuvettes used?

Answer 34

Quartz excels at transmitting a wide range of UV light (190 to 2500 nm)

Question 35

Why does polarity matter when choosing a solvent?

Answer 35

Polarities have to match so that signals aren't swamped

Question 36

Why does solvent cutoff matter when choosing a solvent?

Answer 36

The solvent used must be under the wavelength at which your sample absorbs so that your solvent and sample signals don't overlap