Hydrocarbons:(10)

what is covalent bonding?

Covalent bonding is when two non-metal atoms share pairs of electrons so both achieve a full outer shell; the bonds are very strong, and while simple molecules have low melting/boiling points and don’t conduct electricity. 

What are intermolecular forces?

Intermolecular forces( Van der Waals forces) are weak forces of attraction between molecules. The more electrons the molecule has or the closer together the molecules are, the stronger the intermolecular forces.

what are hydrocarbons and the alkanes? 

• a hydrocarbon consist of hydrogen and carbon atoms ONLY 

• the alkanes are hydrocarbons found in crude oil

What example of a series are the alkanes and what is the general formula? 

• the alkanes are an example of a homologous series( a family of organic compounds with the same functional group and general formula)

• CnH2n+2 

What affects the physical properties of the alkanes? 

• the strength of intermolecular forces affect the substance’s physical properties like boiling point( the temperature at which a substance changes from a liquid to gas), flammability( how easily a substance ignites) , and viscosity( how well a substance flows) 

Describe the physical properties of the alkanes.

• the smaller the molecule the more flammable

• the larger the molecule the higher boiling point

• the larger the the molecule the more viscous( the long chains get tangled and can’t slide past each other)

Explain the difference in properties between straight-chained and branched compounds.

Straight-chain compounds have all carbons in a continuous chain, allowing them to pack closely together, so the intermolecular forces are stronger, giving higher melting and boiling points. Branched compounds have branches that prevent close packing, so their intermolecular forces are weaker, resulting in lower melting and boiling points.

What is crude oil and how is it formed? 

crude oil is a finite fossil fuel, and is a mixture of various hydrocarbons. It was formed over million years as heat and pressure converted ancient biomass( mainly plankton) into crude oil.

Name and describe the method crude oil is extracted into useful alkanes?

• crude oil is very useful but for it to be used as energy the hydrocarbons have to be separated via fractional distillation