[Unknown Username]

Hi!

1. One atomic mass unit (1 amu) is equal to the mass of a carbon-12 atom multiplied by the quantity?
a) 12
b) 1/12
c) 1836
d) 1/1836

2. Fractional distillation is a technique used to separate complex mixtures of hydrocarbons based on differences in their?
a) heats of fusion
b) heats of vaporization
c) melting points
d) boiling points


3. A Bunsen burner flame is sooty black and mixed with an orange-yellow color. Which is the probable reason for this condition?
a) no oxygen is mixing with the gas
b) no gas is mixing with the oxygen
c) insufficient oxygen is mixing with the gas
d) insufficient gas is mixing with the oxygen

My answers:
1. a) 12

2 d) boiling points

3 b) no gas is mixing with the oxygen

Corrections would be gladly accepted
Thanks in advance 

[Astrokel]

Hi Unknown Username, you posted in a wrong section! Anyway,

1. is wrong, please check the definition of amu.
2. is correct
3. if no gas, why would there be flame? so it can't be b. hint: the flame is not totally sooty black!

[Unknown Username]

"The precise definition is that it is one twelfth of the mass of an unbound atom of carbon-12 (12C) at rest and in its ground state."

Errr... my answers are :
1. b) 1/12

3. c) insufficient oxygen is mixing with the gas

[typhoon2028]

1.)  b
One Carbon 12 atom weighs approximately 12 amu

2.) d
Logically, heats of fusion and melting points deal with solids and liquids.  These answers would not make sense for a vapor/liquid separator.  Heat of vaporization is the energy required to change a substance from a liquid to a vapor.  Fractional distallation separates hydrocarbons by boiling point.  In a distallation collumn, higher boiling point materials are at the bottom (heavies) and lower boiling point products at the top (lights).  Also, searching fractional distallation on wikipedia gives you the answer in the first sentence.

3.) c
Just realize some of the gas is being burned just not all of it