Chemistry topic test 3

organic chem and energy

energy

property transferred into a system, recognised as the capacity to do work and can never be destroyed or created

kinetic energy

energy in moving objects

potential energy

stored energy

energy consumption

all the energy used to perform an action, manufacture something, or simply inhabit a building

how energy is used in everyday life

through powering homes, transport, cooking, and running our bodies

how energy is consumed indirectly

producing goods and services

how indirect consumption of energy is associated with production of goods, building homes and infrastructure, energy for transporting and growing food

because energy is required to make, transport and process products, infrastructure, food, etc

direct use of energy in everyday life

consumed directly as fuel or electricity in the car or home

indirect use of energy in everyday life

hidden energy that is required to make, transport, and dispose of goods and services bought

fossil fuel

mixtures of hydrocarbons that formed from the remains of plants and animals that lived millions of years ago in a marine environment

what happens with the concentration of CO2 in the atmosphere as fossil fuels are burning

increases as fossil fuels burn making the atmosphere hotter

why does the concentration of CO2 increase

that carbon in the hydrocarbons that naturally occur in them are exposed to the atmosphere where oxygen is present, making CO2

greenhouse effect 1

high energy short wave radiation emitted by the sun passes through our atmosphere

greenhouse effect 2

50% of this radiation is reflected back into space while the other half hits the earth's atmosphere, heating it up

greenhouse effect 3

a blanket of greenhouse gases around the earth absorb and emit this radiation which regulates the temperature

greenhouse effect 4

an increase in energy from the radiation in the atmosphere cause the molecules of greenhouse gases to vibrate and collide with other gases increasing their kinetic energy

common greenhouse gases

methane (CH4), water vapour (H2O), carbon dioxide (CO2)

local effects of the greenhouse effect

hotter days with more frequent heatwaves, less overall rain, higher risk of bushfires, sea levels rising

global effects of the greenhouse effect weather

longer droughts, more extreme heatwaves, severe storms

global effects of the greenhouse effect everything else

habitats may change or disappear threatening endangered animals, threatens global food security as weather becomes less predictable, melting ice increasing sea levels

organic chemistry

study of compounds of carbon

fractional distillation

separates a mixture into a number of different parts called fractions

fractional distillation 1

crude oil is heated from an external furnace

fractional distillation 2

the oil vaporises, enters the fractionating tower

fractional distillation 3

the larger hydrocarbons (called bitumen) remain as liquids, settling at the bottom of the tower

fractional distillation 4

mixture is heated until all components evaporate together and then cooled so the substances condense separately

fractional distillation 5

more volatile hydrocarbons will continue to rise up the tower

fractional distillation 6

lower molecular hydrocarbons with lower boiling points are collected near the top of the tower

viscosity of hydrocarbons

viscosity increases as carbon length increases

volatility of hydrocarbons

volatility decreases as carbon length increases

flammability of hydrocarbons

flammability decreases as carbon length increases

alkane homologous

CnH2n+2

alkene homologous

CnH2n

alkyne homologous

CnH2n-2

cycloalkane homologous

CnH2n

cycloalkene homologous

CnH2n-2

functional group

atom or a group of atoms responsible for the typical chemical reaction of a molecule, determine pattern of reactivity in homologous series

alkane functional group

none

alkene functional group

at least double bond

alkyne functional group

at least triple bond

cycloalkane functional group

in a shape with all single bonds

cycloalkene functional group

in a shape with at least one double bond

saturated hydrocarbon

hydrocarbons with only single bonds, they are bonded to as many hydrogen atoms as they can

unsaturated hydrocarbon

hydrocarbon with at least a double bond, triple bond or a ring between carbon atoms

alkane

prefix+ane

alkene

prefix+ene

alkyne

prefix+yne

cycloalkane

cyclo+prefix+ane

cycloalkene

cyclo+prefix+ene

one chem

meth

two chem

eth

three chem

prop

four chem

but

five chem

pent

six chem

hex

seven chem

hept

eight chem

oct

condensed formula

everything you see written out

condensed substituents

in brackets

molecular

everything added together

IUPAC naming system 1

find the longest carbon chain (if the same, the one with the heavier molecular mass)

IUPAC naming system 2

number the carbon chain (depending on mass)

IUPAC naming system 3

subsitutents are placed in front of the names

IUPAC naming system 4

named in alphabetical order (remove prefixes)

one

mono

two

di

three

tri

four

tetra

five

penta

predict outcome of combustions

always check oxygen supply first

complete combustion

has unlimited amount of oxygen, makes CO2 and water

incomplete combustion

has limited amount of oxygen, makes CO and water

combustion molecular equation

hydrocarbon + O2 --> CO2 + H2O

exothermic

energy flows from the system to surroundings

exothermic surroundings

surroundings become hotter

exothermic PE

reactants have more potential energy than products

endothermic

energy flows from the surroundings to the system

endothermic surroundings

surroundings become colder

endothermic PE

reactants have less potential energy than products

endothermic energy change

+∆H because absorbs heat from surroundings

exothermic energy change

-∆H because releases heat into surroundings

2H2O + energy → 2H2(g) + O2(g); ∆H = +572kJ

endothermic

2H2O + energy → 2H2(g) + O2(g); ∆H = +572kJ terms

572kJ of heat energy is absorbed from the surroundings when 2 moles of liquid water decomposes into two moles of gaseous H2 and one mole of gaseous O2

H2(g) + Cl2(g) → 2HCl(g) + energy; ∆H = -184kJ

exothermic

H2(g) + Cl2(g) → 2HCl(g) + energy; ∆H = -184kJ terms

184kJ of heat energy is released into the surroundings when one mole of gaseous H2 reacts with one mole of gaseous Cl2 to make 2 moles of gaseous HCl

activation energy

energy required for reactants to be able to react with each other

features of catalyst

doesn't get used up or changed and can be reused, and provides an alternate route where lower activation energy is required

how catalysts speed up chemical reaction

when it is used, catalysts provides a lower activation energy barrier which increases the rate of reaction by increasing the chance of collisions

energy profile diagrams endothermic

has a positive enthalpy meaning the arrow is going up and the reactants have less potential energy than products

energy profile diagrams exothermic

has a negative enthalpy meaning the arrow is going down and the reactants have a higher potential energy than products

energy profile diagrams transition state

between the reactants and products

energy profile diagrams catalyst

have to show with and without a catalyst which are labelled and having a catalyst means it has a lower activation energy than the original

energy profile diagram activation energy

endo and exo reactions both have forward and reverse activation energy

forward activation energy

from the reactants to the peak of activation energy

reverse activation energy

from the products to the peak of activation energy

∆H

forward activation energy - reverse activation energy

endothermic energy

is in the reactants

exothermic energy

is in the products

the higher the negative enthalpy

the longer the carbon chain

higher negative enthalpy why

means more energy was required which means the fuel is more powerful