Chem Review Flashcards
Types of chemical
reactions for alkanes
Combustion
Substitution
Cracking
Types of chemical reactions for alkenes and alkynes
Combustion
Addition
Polymerization
What is cracking?
is a process by which HC are broken into smaller more useful molecules
Fractional distillation is..
is petroleum refining according to boiling points, lower boiling point
substance separates first
Chemical reactivity of hydrocarbons
Alkynes> Alkenes >»_space;»> alkanes
Expanded structural formula
H H H H
I I I I
H-C-C-C-C-H
I I I I
H H H HCondensed structural formula
H2 H2
H3C-C-C-C-CH3
C-C-C-C
Skeletal structural formula
Physical and chemical properties of hydrocarbons
1.Carbon has 4 valence electrons and can do 4 bonds/ Carbon can do single,
double and triple bonds (covalent bonds)
- CH bond is a non- polar bonds as the difference is very smalls
- Hydrocarbons are non-polar compounds bonded by very weak Van Der Waals attraction
- Small chain hydrocarbons are expected to be gas or liquid at room temperature.
- They are expected to have low boiling & melting points too.
- Since hydrocarbons are non-polar they dissolve in non-polar solvents and do not dissolve in polar solvents
- C-H bond is a stable bond have very low chemical reactivity
Why are alkanes saturated and Alkynes and alkenes not?
Because u can still add (saturate) it with Hydrogen atoms.
Halocarbon properties
Increasing the x molar mass increases BP & MP
Can be primary, secondary & tertiary (
depends on carbons attached to the
carbon)
Alcohols properties
Dissolves in water - Hydrogen bond • Increasing -OH increases polarity/solubility/BP & MP Separated from water by distillation Can be primary, secondary & tertiary ( depends on carbons attached to the carbon) A glycol is an alcohol with more than one - OH Glycerol is a tripropanol Uses: Butanol: dissolves dyes Glycerol (have 3-oh): used as antifreeze for planes fuel.
Ether properties
Despite having -O- it doesn’t form a h-bond
Uses:
diethyl ether: is a surgical anesthetic
Amine properties
-Responsible for the bad smell of cadavers(
Dead bodies), police dogs can recognize to
look for bodies.
Can be primary, secondary & tertiary
(depends on carbons attached to it)
Slightly basic compounds: Indicators
Aldehydes
do not form hydrogen bond with each other
Can make hydrogen bond with water
- USes
Formaldehyde: Used to preserve biological
specimen for years
Reacts with Urea to make rigid wax and plastic
(buttons)
Ketones properties
- less polar than aldehyde
Uses: solvent for non-polar compounds:
Industrial solvent/ dissolve stains of non polar
compounds like wax
Carboxylic acid properties
can form hydrogen bond - highly polar - acidic in nature: indicators Examples: salicylic Acid, adebic acid - Formic acid: is a chemical that ants produce as a signal for danger.
Esters properties
Polar compounds Gives the smell for natural & industrial smells Methyl hexanoate: strawberry Ethyl butanoate : pineapple
Amides properties
When in carboxylic acid an -OH is
replaced with NH grp
Only carboxylic acids, primary & secondary amines and alcohols can make h-bond with themselves
make h-bond with themselves
the number or halogens in a structure will increase
its boiling points
________ the carbon atoms will increase the boiling point
Increasing
Increasing the carbon atoms will?
Increasing the carbon atoms will decrease the solubility
Aromatic compounds have a higher boiling point than
Aromatic compounds have a higher boiling point than aliphatic compounds
Solubility in water & Boiling point order:
RCOOR > ROH> RNH2> RCHO> RCOR> ROR> R-X
C.a> alcohol > amine> aldehyde> ketone > other> alkyl halides> alkene> alkane
Increasing the branches will ..
Increase the distance between the molecules,it will decrease the boiling point.
Weaker dispersion bonds leads to..
Less energy needed to break the bonds less boiling point.
Formula for finding alkanes
CnH(2n+2)
Formula for finding alkenes
CnH2n
Alkynes formula
CnH(2n-2)
