Chemistry Exams Questions

1) When a little quantity of ethanol (b. pt 78 0C) was dissolved in large quantity of water (b.pt 100

0C) , the most likely boiling point of the mixture is between

A. 89-90 0C

B. 103-1070C

C. 78-100 0C

D. 80-96 0C

2) Chromatography is a method of separation based on

A. the different speed of the components

B. the ability of the components to react with each other

C. the ability of the components to repel each other

D. the absorption of the components into each other

3) A compound on analysis contains 40% of carbon, 6.6% of hydrogen and the rest oxygen. What is

the empirical formula of the compound?

A. CH2O

B. CHO

C. C6H12O6

D. C2H4O

4) The formula C2H2 for benzene is regarded as its

A. molecular formula

B. structural formula

C. empirical formula

D. perspective formula