Chem exam coming up...more review questions stuck on...plz help?

Question

1. Organic compounds have only Cs and Hs rite?
2. How is fractional distillation used to seperate the components of crude oil? (what is it?)
3. classify reaction as refomring, cracking, or complete combustion then complete a possible chemical equation: C4H10 + O2 --> (given a line) (how to tell whether its complete or incomplete combustion if just given reactants?
4. Given the following structural diagrams. what are its names? (CH3)4C and (CH3)2CHCH(CH3)2 (<--no lines connecting Cs)
5. How do i know i have found all the isomers for C3H6 and C5H10...i drew 2 for each already...more?
6. Indicate which hydrocarbon familes (alkanes, alkenes, etc) have the following characteristcs: a) form geometric isomer b) form structural isomers c) undergo combustion reactions

THANK YOU SOO MUCH!!

6 (in more detail):
Hydrocarbons are a valuable raw material for the petrochemical
industry. Often a particular isomer is used as
the basis of a specific paint, plastic, or pharmaceutical
product. Indicate which hydrocarbon families (alkanes,
alkenes, alkynes, cycloalkanes, cycloalkenes) have the
following characteristics:
(a) form geometric isomers
(b) form structural isomers
(c) undergo combustion reactions

THX!!!

Answer 1

3. I think that your reaction is complete combustion because in cracking (uncomplete combustion) you need a carbon as reactant.
So your reaction would be:
2C4H10 + 15O2 --> 8CO2 + 10H2O
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4. When you have that kind of formulas (they are called strucutural formulas) written, you need to suppose based on group, which has been written, what type of C-C bond is it.
(CH3)4C = ((CH3)4-C) = 2,2-dimethyl-propane
(CH3)2CHCH(CH3)2 = (CH3)-CH(CH3)-CH(CH3)-(CH3) = 2,3-dimethyl-butane
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5. Well, you don't. I don't know that there is any specific rule (There might be some). You just try to find all of them.
C3H6 has only one (1) isomer. That's: CH3-CH=CH2
But, C5H10 has (5) five of them:
CH2=CH-CH2-CH2-CH3
CH3-CH=CH-CH2-CH3
CH2=C(CH3)-CH2-CH3
CH2=CH-CH(CH3)-CH3
CH3-C(CH3)=CH-CH3
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6. I don't get your sixth question. Can you explain it some more, pls?

Answer 2

1) Wrong. Hydrocarbons have C and H only, organic compounds have C combined to H, O, N, P, etc.

2) Fractional distillation is a method of separating materials based on their different boiling points. The material with the lowest BP will boil away first. It is cooled and condensed to a liquid then collected in a separate vessel. The next lowest BP material will boil when the temp rises to its BP. It is collected the same way. This process continues with raising BP until nothing but a sludge material is left as a waste product. This waste is burned to get rid of it.

Answer 3

The surface area of a square-based pyramidal candle with a base side length of 8 cm and a slant height of 10 cm: The square area = 64 cm^2 Height of the pyramid = sqrt (39) cm Surface area of the sides of the pyramid = 20 sqrt 39 cm^2