CHEM 238 COMPREHENSIVE STUDY GUIDE
COMPLETE QUESTIONS AND CORRECT
ANSWERS
●● Safety
If chemicals get into your eyes, the first thing you should do is to:
a. wash out your eyes in the eye wash station
b. run around the lab frantically
c. tell your T.A. about it
d. use the safety shower
Answer: A
●● Safety
If a strong acid comes into contact with your skin, wash the affected area
with cold water and apply:
a. dilute sodium acetate
b. dilute sodium bicarbonate
c. dilute sodium hydroxide
d. dilute sodium hydride
e. none of these
Answer: B
,●● UV Sunscreens
SPF refers to product effectiveness against the _____ rays of the sun.
a. UVA
b. UVB
c. UVC
d. UVA + UVB
e. UVA + UVB + UVC
Answer: B
●● UV Sunscreens
The organic compounds in sunscreen typically work because they _____
the ultraviolet light that comes into contact with them.
a. deflect
b. reflect
c. absorb
d. none of the above
Answer: C
●● UV Suncreens
Beer's Law formula is:
a. c=elA
b. A=el/c
,c. Ae=lc
d. A=elc
e. Al=ec
Answer: D
●● UV Sunscreen
Which of the following UV rays can penetrate the Earth's atmosphere?
a. UVA
b. UVA and UVB
c. UVA and UVC
d. UVB and UVC
e. UVA, UVB, and UVC
Answer: B
●● UV Sunscreen
When a molecule absorbs visible or UV light, which of the following
transitions takes place?
a. electrons in lower molecular orbitals are excited into orbitals of higher
energy
b. electrons in molecular bonds are excited from lower vibrational states
to higher vibrational states
c. atomic nuclei are excited from lower nuclei states to higher ones
d. molecules are excited from lower rotational states to higher ones
, e. none of these
Answer: A
●● UV Sunscreen
Which of the following statements about the SPF, sunscreen protective
factor, values for
sunscreens is false?
a. you should choose the SPF based on your skin type and the amount of
time you plan to
be in the sun
b. SPF refers to product effectiveness against both UVA and UVB
radiation
c. as SPF values increase, you get better UVB protection for the same
amount of time in
the sun
d. as SPF values increase you can stay longer in the sun before you start
getting sunburn
e. SPF = (MED for the skin with sunscreen)/(MED for skin without
sunscreen), where MED
is minimal erythemal dose
Answer: B
●● UV Sunscreen
COMPLETE QUESTIONS AND CORRECT
ANSWERS
●● Safety
If chemicals get into your eyes, the first thing you should do is to:
a. wash out your eyes in the eye wash station
b. run around the lab frantically
c. tell your T.A. about it
d. use the safety shower
Answer: A
●● Safety
If a strong acid comes into contact with your skin, wash the affected area
with cold water and apply:
a. dilute sodium acetate
b. dilute sodium bicarbonate
c. dilute sodium hydroxide
d. dilute sodium hydride
e. none of these
Answer: B
,●● UV Sunscreens
SPF refers to product effectiveness against the _____ rays of the sun.
a. UVA
b. UVB
c. UVC
d. UVA + UVB
e. UVA + UVB + UVC
Answer: B
●● UV Sunscreens
The organic compounds in sunscreen typically work because they _____
the ultraviolet light that comes into contact with them.
a. deflect
b. reflect
c. absorb
d. none of the above
Answer: C
●● UV Suncreens
Beer's Law formula is:
a. c=elA
b. A=el/c
,c. Ae=lc
d. A=elc
e. Al=ec
Answer: D
●● UV Sunscreen
Which of the following UV rays can penetrate the Earth's atmosphere?
a. UVA
b. UVA and UVB
c. UVA and UVC
d. UVB and UVC
e. UVA, UVB, and UVC
Answer: B
●● UV Sunscreen
When a molecule absorbs visible or UV light, which of the following
transitions takes place?
a. electrons in lower molecular orbitals are excited into orbitals of higher
energy
b. electrons in molecular bonds are excited from lower vibrational states
to higher vibrational states
c. atomic nuclei are excited from lower nuclei states to higher ones
d. molecules are excited from lower rotational states to higher ones
, e. none of these
Answer: A
●● UV Sunscreen
Which of the following statements about the SPF, sunscreen protective
factor, values for
sunscreens is false?
a. you should choose the SPF based on your skin type and the amount of
time you plan to
be in the sun
b. SPF refers to product effectiveness against both UVA and UVB
radiation
c. as SPF values increase, you get better UVB protection for the same
amount of time in
the sun
d. as SPF values increase you can stay longer in the sun before you start
getting sunburn
e. SPF = (MED for the skin with sunscreen)/(MED for skin without
sunscreen), where MED
is minimal erythemal dose
Answer: B
●● UV Sunscreen
