Alkanes Flashcards
What is free radical substitution?
A reaction involving the substitution of atoms in a molecule by free radicals.
What role does UV light play in free radical substitution?
UV light provides the energy to break covalent bonds, creating two radicals.
What is a radical?
An atom or molecule with a single unpaired electron, represented by a (.) in equations.
What occurs during the initiation step of free radical substitution?
The halogen is broken apart by UV light to create two free radicals.
What happens during the propagation step?
The reaction propagates through two steps, also known as a chain reaction.
What is the termination step in free radical substitution?
Two radicals collide to form a molecule with all electrons paired, stopping the reaction.
What can two methane radicals create?
They can react to create ethane.
What are hydrocarbons?
Hydrocarbons are molecules that only contain carbon and hydrogen.
What is combustion?
Combustion is when something reacts with oxygen.
What is the general equation for the combustion of alkanes?
Alkane + Oxygen = Carbon dioxide + Water.
What is the balanced equation for the combustion of methane?
CH4(g) + 2O2(g) = CO2(g) + 2H2O(L)
What is free radical substitution?
A reaction involving the substitution of atoms in a molecule by free radicals.
What role does UV light play in free radical substitution?
UV light provides the energy to break covalent bonds, creating two radicals.
What is a radical?
An atom or molecule with a single unpaired electron, represented by a (.) in equations.
What occurs during the initiation step of free radical substitution?
The halogen is broken apart by UV light to create two free radicals.
What happens during the propagation step?
The reaction propagates through two steps, also known as a chain reaction.
What is the termination step in free radical substitution?
Two radicals collide to form a molecule with all electrons paired, stopping the reaction.
What can two methane radicals create?
They can react to create ethane.
How many sigma bonds does each carbon form in alkanes?
Each carbon forms 4 sigma bonds.
What is the bond angle in an alkane?
The bond angle is 109.5 degrees.
What is the 3D shape of an alkane?
The 3D shape of an alkane is tetrahedral.
How do we identify an alkane at GCSE level?
We identify an alkane by its double bond.
How many sigma bonds does each carbon form in alkenes?
Each carbon atom forms 3 sigma bonds.
What is the bond angle in an alkene?
The bond angle is 120 degrees.
What is the shape around an alkene?
The shape around an alkene is trigonal planar.
What are the leftover carbon electrons in an alkene called?
They are known as a P-orbital.
What do two P-orbitals overlap to form?
They overlap to form a pi bond.
What forms a double bond in alkenes?
A pi bond and a sigma bond come together to form a double bond.
Which bond is weaker, pi bond or sigma bond?
A pi bond is weaker than a sigma bond.
Why is a sigma bond stronger than a pi bond?
In a sigma bond, the orbitals overlap and point directly at each other, whereas in a pi bond they aren’t overlapped nor facing each other.
What is the shape of P-orbitals when viewed in 3D?
P-orbitals are dumbbell shaped.
