Chem Test

How do you determine the melting and boiling point of Alkanes and Alkenes

Through the molar mass of the molecule, as the bigger the molecule meaning the longer the chain there would be more electrons therefore increasing the strength of dispersion forces. This means more energy is required to break the bonds meaning a higher melting and boiling point.

What are the 3 main characteristics of members in a homologous series

1. Each member contains one more -CH3 than the other

2. Physical Properties, as the chain increases and the molecule grows larger, the boiling and melting point increases

3. Chemical proprties are the same among all homologous groups as they contain the same functional group

Describe the main properties of the hydrocarbon groups (polarity, solubillity, and reactibillity)

Nonpolar: Alkane, Alkene, Alkyne

Polar: Haloalkane, alchohol, aldehyde, ketones, carboxylic acids.

non-soluble: Alkanes, Alkenes, Alkynes

Both: Alchohol, Haloalkanes

Soluble: Aldehydes, ketones, carboxylic acids

reactibillity: Alkane is least reactive, alkyne is most reactive

Compare the reactivity of Alkanes and Alkenes via bromine water

Alkanes don’t react suddenly react as there is no bonds for bromine to bond to, therefore UV light is used to cause a reaction.

Alkenes react more suddenly as the double bond breaks allowing bromine to be added to the molecule in an addition reaction.

How can dichromate solution be used to distinguish between primary, secondary, and tertiary alchohols

When oxidised dichromate solution is reacted with primary and secondary it oxidises primary alchohol to aldehydes them carboxylic acids and secondary alchohols to ketones. This therefore causes a colour change from orange to green therefore signalling a reaction.

However, there is no reaction for teritary alchohols therefore the orange solution remains orange

How can alchohol be dispersed in water

Alchohol is a polar molecule thus it is soluble in water and is able to form attractions with polar water molecules and bond through hydrogen bonding

1 chemical and physical property of alchohol

It is soluble and can undergo oxidisation into aldehyde, carboxylic acids, and ketones.

Explain addition reactions

Typically occurs with alkenes as they are unsautrated, where the double bonds are broken and replaced with other elements to add to those broken bonds.

What are the physical properties of the intermolecular forces

Hydrogen Bonding: Highest boiling, melting point, and viscosity

Dipole Dipole Reactions: Moderate boiling and melting point.

Dispersion Forces: lowest boiling and melting point and lowest viscosity.

Explain boiling point in terms of HF, H2O, and NH3

Water has the highest boiling point as it has the most lone pairs out of the 3, therefore it can bond to more molecules easily making it harder to separate thus requiring higher energy indicating a higher boiling point.

How does the strnegth increase in dipole dipole bonding

increased polairty and electrons

How to determine difference between dipole dipole and dispersion.

Dispersion forces usually occur between non-polar molecules

Dipole dipole usually occur between both non polar and polar molecule.

How to make combustion reaction

When given oxygen and hydrocarbon, on products add H2O (Water) and CO2/CO (Carbon Dioxide/Monoxide), then balance.