Ch - 19 (Reactions to organic compound) Flashcards
Define fossil fuels.
A substance which when burned, releases heat energy
What are the most common fossil fuels?
coal, natural gas, petroleum
What is methane?
the main constituent of natural gas and is a hydrocarbon.
What are hydrocarbons made up of?
Hydrogen and carbon atoms
How are fractions in petroleum separated?
fractional distillation
Define petroleum.
- a mixture of hydrocarbons which also contains natural gas
- Crude oil
- thick, sticky, Black liquid that is found under porous rocks
what does molecule in each fraction have?
- similar properties
- similar boiling points (depends on number of carbon atoms)
- contain alkanes
what is the size of each molecule in a fraction related to?
How many carbon and hydrogen atoms the molecules contains
What is fractional distillation carried out in?
-Fractionating column which ahs temp gradient
- hot at bottom n cool at top
What happens during the process of fractional distillation?
- crude oil heats up and vaporizes
- vapor of hydrocarbons enters the column which has a temp gradient
- vapor with high b.p. condense at bottom of the column.
- vapor of hydrocarbons with lower b.p. rise up the column and Condense at the top.
What are the main properties of fractions?
- Viscosity
- M.p. / B.p.
- Volatility
Describe detailS about viscosity.
- ease of flow of liquid
- High viscosity are thick & flow less easily
- no. of carbon atom increases, attraction between hydrocarbon molecules increases
- liquid becomes more viscous, increasing length of hydrocarbon chain
- going down column, viscosity of fraction increases
Describe details about M.p. / B.p.
- molecules get larger, intermolecular attraction becomes greater
- more heat is needed to sperate molecules
- going down the column, b.p. of fractions increases
Describe details about volatility.
- tenancy of a substance to vaporize
- size of hydrocarbon increases, attraction between molecules increases
- going down column, volatility of fractions decreases
What are the uses of fractions?
- Refinery gas: Heating and cooking
- Gasoline: Fuel for cars
- Naphtha: Raw product for forming chemicals
- Kerosene: For making jet fuel
- Diesel: Fuel for diesel engines
- Fuel oil: Fuel for ships and home heating
- Lubricating oil: Lubricants, polishes, waxing
- Bitumen: Surfacing roads
What are alkanes?
Group of saturated hydrocarbons
What does the term saturated mean?
- Have single carbon - carbon bonds
- covalent bonds (only non metals)
what is the general formula of alkane?
CnH2n+2
What is a physical description of alkanes?
- colorless compounds
- hugs change of colorless compounds
What are the properties of alkanes?
- unreactive compounds
- undergo combustion reactions
- cracked in small molecules
- React with halogen in presence of light
What is chemical equation of methane undergo complete combustion?
CH4 (g) + 2O2 (g) –> CO2 (g) + 2H2O (l)
What are the names of alkanes?
- Methane
- Ethane
- Propane
- Butane
- Pentane
What is molecular formula of:
- Methane
- Ethane
- Propane
- Butane
- Pentane
- Methane = CH4
- Ethane = C2H6
- Propane = C3H8
- Butane = C4H10
- Pentane = C5H12
What happens in substitution reaction of alkanes with halogens?
- one atom (or group of atoms) is wrapped with another atom (or group of atoms)
- undergoes substitution in presence of UV radiation
- called photochemical reaction
- UV light provides activation energy for reaction
- hydrogen atoms is replaced by halogen atom
What are alkenes?
- unsaturated hydrocarbons
- double bonds (C = C)
- covalent bonds
What is general formula for alkene?
CnH2n
What does double bonds in alkenes mean?
- make more bonds of other atoms by opening up the bond
- carbon atom forms 4 single bonds
- more reactive than alkanes
What are the names of alkenes?
- Ethene
- Propene
- But - 1 - ene
- Pent - 1 - ene
What is the molecular formula of alkenes?
- Ethene (C2H4)
- Propene (C3H6)
- But - 1 - ene (C4H8)
- Pent - 1 - ene (C5H10)
How are products made from by manufacturing of alkenes?
long chains of hydrocarbons molecules are further processed