Alkanes Flashcards
(29 cards)
What is the structure of a cyclohexane
They have a ring of carbon atoms with two hydrogen’s attached to each carbon
What is the general formula of a cycloalkane (assuming there is only one ring)
CnH2n
Are cycloalkanes saturated or unsaturated ?
Saturated
What is petroleum
Crude oil
What do boiling points measure
The strength of the intermolecular forces between molecules (high boiling points mean strong intermolecular forces
What is the long full name of wan der waals
Instantaneous induced dipole forces
Explain what wan der waals are
Electron movement in a molecule causes a temporary dipole. This induces a dipole in another molecule. The attraction of the dipoles on different molecules is an attractive force,
What does having more electrons create in wan der waals
Stronger forces
Do branches cause lower or higher boiling points in molecules (why)
Lower boiling points (because the molecules are less spread out)
What is a permanent dipole
Where one element is attracted to the electrons more than another element
What do we call the atoms that are more attracted to the electrons
Electron negative
Can permanent dipoles act as intermolecular forces
Yes
What is crude oil formed from
The slow decay of marine animals and plants over millions of years
Do you get permeant dipoles in alkanes
No
As the chain becomes longer what happens to the hydrocarbons
They become : More viscous Harder to ignite Are less volotile Have higher boiling points
Give four examples of homologous series
Alkanes
Alkenes
Alcohols
Haloalkanes
What five things do homologous series have in common
- they all have the same functional group
- there chemicals similar
- they have a gradual trend in the physical property’s (eg melting point)
- members differ by -CH2-
- they have the same general formula
What homologous series does crude oil contain
Alkanes
What’s the molecular formula for benzene
C6H6
What temperature does thermal cracking happen at
A very high temperature (around 900 degrees)
What is the pressure needed for thermal cracking
70 atm
What are the products of thermal cracking
Alkenes
What is the temperature needed for catalytic cracking
450 degrees
What is the aptomspheric pressure needed for catalytic cracking
1-2 atm
