The empirical formula of a compound is CH2O. It is known that the molecular mass of this compound is 90.0. What is the molecular formula of this compound? ( )
A. CH2O
B. C2H4O2
C3H6O3
D. CH3CH(OH)COOH
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Which one is a strong electrolyte? ( )
A. SiO2
B. H2O
C. HNO3
D. NH3
15 104 (52)For a process to occur spontaneously, ( )
A. the entropy of the system must increase
B. the entropy of the surroundings must increase
C. both the entropy of the system and the entropy of the surroundings must increase
D. the net change in entropy of the system and surroundings considered together must be a positive quantity
Our perception of sweetness in wine is enhanced at higher temperatures.
A. True
B. False
Rieslings are usually __________ wines with high natural acidity and distinctive _________ attributes. The presence of toasty, kerosene notes indicates __________.
A. light-bodied / vegetal, grassy and tropical / oak maturation
B. full-bodied / vegetal, grassy and tropical / bottle aging
C. full-bodied / floral, apple and citrus / oak maturation
D. light-bodied / floral, apple and citrus / bottle aging
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