organic chemistry 2 (lesson 3 - 5) Flashcards
What are some signs of complete combustion?
blue flame, its smokeless, soot less, and give off more heat
What are the signs of incomplete combustion?
yellow and orange flames, smoke and soot, less heat.
what are the products for an incomplete combustion reaction?
carbon, carbon monoxide, carbon dioxide.
In addition to water and energy
what forms of petroleum are there?
natural gas, crude oil and oil sand deposits
what are petrochemicals used in?
the production of plastics
what types of natural gas are there?
two types:
1. Sweet - little to no sulfur
2. sour - has sulfur: H₂S (extremely toxic), sulfur oxides (acide deposition)
What is the process of sulfur extraction called? and what happens
clause process
Burning: Some of the hydrogen sulfide is burned with oxygen. This creates a gas called sulphur dioxide and water.
Mixing: The remaining hydrogen sulfide is mixed with the sulfur dioxide gas. They react together to form solid sulfur.
Collecting: The solid sulfur is separated from the gas mixture and collected.
Cleaning: The leftover gas is treated to remove any remaining hydrogen sulfide.
What is natural gas mostly comprised of?
mostly methane with some ethane and propane.
How is a crude mixture separated (purified)?
fractional distillation
How/why does fractional distillation work?
- because of the different boiling points of the components of crude oil.
- The lighter the molecule and the lower the boiling point, the higher it rises in the tower.
What is Solvent extraction?
Solvent extraction uses a solvent to selectively dissolve/remove an impurity or to separate useful products
What are the two types of reactions in petroleum refining?
Cracking - Breaks long-chain hydrocarbons into smaller units
* cracking requires heat and pressure
* There are many different types of cracking reactions, forming different products (alkanes, alkenes)
* Hydrocracking REQUIRES H₂ (g)
Reforming - small hydrocarbons are joined to make larger molecules and increase branching
* requires heat and pressure
* There are several; types of reforming reactions; one of which is alkylation to produce “high octane” gasoline
* all reforming reactions PRODUCE H₂ (g)
What are the main points for fractional distillation and solvent extraction?
- Fractional distillation and solvent extraction is a process that can be used to separate an organic compound from a natural mixture
- Fractional distillation of crude oil (petroleum) uses the principle of varying boiling points for separation
- Solvent extraction is a method to separate compounds based on their relative solubilities in two different immiscible liquids. We add a liquid to a mixture and the organic compound “repels it” and separates.
why does the boiling point higher for larger alkanes?
When an Alkane is larger the strength of the LD forces is greater between molecules because of the greater amount of electrons.
organic halides characteristics
- organic compounds where hydrogen has been replaced by one or more halogens (F, Cl, Br, I)
- can be nonpolar or polar (soluble or insoluble)
- toxic and dangerous
- increased substitutions cause greater LDF between molecules, thereby increasing BP
- BP increases if substitutions are halogens from lower in the group (larger atoms)
Characteristics of substitution reactions
Substitution reactions:
* add X₂ to produce R-X + H-X, X represents halogen ion
* almost always requires uv light, catalysts,
* Usually has a reactant with single bonds only.
* Halogen coefficient -> how many H’s are replaced
characteristics of addition reactions
Addition reactions:
* A double or triple bond in an alkene or alkyne is broken and a group or element is added ( a catalyst is present)
* There are four types of addition reactions
* Adding X₂, HX, H-OH, H₂
What happens in an elimination/alcohol reaction?
- alcohol forms an alkene plus water
- opposite of addition reactions
- organic halides can react with a base (OH) to produce an alkene, halide ion and water
what are the three types of alcohols and what is their diagram?
O - H O - H O - H
| | |
R - C - H R - C - H R - C - R
| | |
H R R
Primary Alcohol Secondary Alcohol Tertiary Alcohol
What is an unusual case for naming alcohols
- OH
|
/ \
|O |
\ /
Phenol (benzene ring with OH)
What is the formula for organic halides?
R - X
where R is the ring
and X is the halogen
what are the uses for organic halides?
DDT, PCB, CFC
anesthetics
dry cleaning fluid
plastics, polymers
Types of addition reactions
- Halogenation (adding X₂)
- Hydrohalogenation (adding HX)
* often more than one possibliity is present in many cases, because of the asymmetrical way that HX adds - Hydration (adding H-OH)
* also often more than one possibility! - Hydrogenation (adding H2)
characteristics/properties of alcohols
- formula: R-OH
- Have much higher BP’s than corresponding aliphatics because of hydrogen bonding
- polar
- the -OH end of the alcohol is polar while the carbon chain end is not therefore small alcohols are soluble in water and large alcohols are not.
