老友网138. A researcher is working in lab where hazardous liquid chemicals are present.Which of the following is not considered appropriate personal protective equipment for this situation?
a.Open toed shoes.
b.Lab coat.
c.Chemical resistant gloves.
d.Chemical splash goggles.(正确答案)
139. The desire to maintain a safe laboratory environment for all begins with （）?
a.prevention(正确答案)
b.ubiquity
c.microbiology
d.accidents
140.Good work practices include,
a.smelling and tasting chemicals
b.not washing hands before and after lab
c.confining long hair and loose clothing
d.using damaged equipment and glassware.(正确答案)
141.While conducting a dangerous experiment, there should be operators.
A.one
B.two or more(正确答案)
C.three or more
142.Which of the following items is not a highly toxic chemical?
A.Potassium cyanide (KCN)
B.Sodium azide (NaN3)
C.Thallium (Tl)
D.Methanal (HCHO)(正确答案)
143.In what direction should we evacuate after a hazardous chemical accidents?
A、downwind
B、upwind(正确答案)
144. What are the unit of LD50 for acute toxicity of hazardous chemicals?
A.mg/kg(正确答案)
B.g/kg
C.mL/kg
D.ug/kg
145. The half-life of radon is 4 days.After 8 days, what is the residual amount of radon?
A.1/2
B.1/4(正确答案)
C.1/8
D.1/16
146. Carbon dioxide fire extinguishers are mainly used to put out the initial fire of .
A.expensive equipment and files
B.instruments and meters, electrical equipment under 600 volts
C.oil.
D.all above(正确答案)
147. The maximum allowable temperature of using a constant temperature incubator is ℃.
A.60(正确答案)
B.100
C.45
D.80
148.28.take into account the risk of electric shock.
A.36
B.65
C.25(正确答案)
149.When used properly, chemical fume hoods protect you from:
A.Chemical splashes, so you don’t have to wear eye protection.
B.Hazardous fumes or vapors.(正确答案)
C.Fire.
D.Loud noises.
150. Teachers and students who enter the laboratory to work should strictly obey the laboratory operating rules, and turn off（）, lock the doors and windows before leaving the laboratory after finishing the experiment, to prevent fire and explosion, overflow and other accidents.
A、the instruments and equipment
B、the water source, power source, air source(正确答案)
C、Computers
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