Which is not a pure substance?
A. helium
B. copper wire
C. air
D. sucrose
Which of these statements about biodiesel is not true?
A. Biodiesel is made from renewable resources such as vegetable oils and animal fats.
B. Biodiesel is non-toxic and biodegradable.
C. Biodiesel can be used in diesel engines without major modifications.
D. Biodiesel has been withdrawn from several states due to health concerns.
The diagram below shows a simplified version of a fractionating column used in the
petroleum industry.
The position marked ___ corresponds to the cracker where large molecules are broken
into smaller molecules.
A. A
B. B
C. C
D. D
A disadvantage of ozonation over chlorination is
A. the higher cost of ozonation.
B. ozonation does not protect the water after the initial process is complete.
C. the higher cost of ozonation and ozonation does not protect the water after the initial
process is complete.
D. None of these choices is correct.
What is the difference between a fat and an oil?
A. A fat is a triglyceride, an oil is a monoglyceride.
B. A fat is solid, while an oil is liquid at room temperature.
C. A fat is a lipid, an oil is not.
D. A fat is made from fatty acids, an oil is made from oily acids.
In an electrochemical cell, the anode is
A. the electrode at which oxidation takes place.
B. the material used to connect the two half cells to each other.
C. always used up before the cathode.
D. never a metal.