Chemistry Flashcards
What happens to the electrons of metallic bonding
The electrons in the outershelll are delocalised
What is metallic bonding
Strong forces of electrostatic attraction between positive metal ions and the shared negative electrons
What does equilibrium mean
when both reactions are happening so they affectively cancel each other out
What is a reversible reaction
a reversible reaction is when the products of the reaction can be used to create the reactants.
What is Potable water
Water that is safe to drink
Name the first 10 alkanes in order
methane
ethane
propane
butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
What are hydrocarbons
Compounds that are made up of the elements hydrogen and carbon only
What is the general formula for an alkane
CnH2n+2
What bonds are Alkanes held together by
single bonds
What qualities do long chain hydrocarbons have
they have high melting points due to strong inter-molecular forces
What qualities do short chain hydrocarbons have
they have low melting points due to weak intermolecular forces
How is crude oil is processed
crude oil is separated using a technique called fractional distillation
The equipment used to separate crude oil is a fractional column
the column is hot at the bottom and cold at the top
this means that short chain hydrocarbons evaporate at the bottom and then condense back into liquid at the top
while long chain hydro carbons are left at the bottom
What is Cracking
an example of thermal decomposition where long chain hydrocarbons are broken down into smaller ones
What are the products of cracking a long chain hydrocarbon
a short chain alkane and an alkene
What are Alkenes
a different form of hydrocarbons that is double bonded
What is the formula for alkenes
CnH2n
What are alkenes used for
Alkenes are used to make polymers such as polyethene and polypropene
What is polyethene used for
plastic bags
bottles
dustbins
What is polypropene used for
it is used to make tough plastics
What happens when an alkane is added to bromine
it doesn’t change colour.
Why does Bromine not change colour when an alkane is added to it
Alkanes are saturated hydrocarbons so they don’t have double bonds that can be broken to accept bromine molecules
What happens when an Alkene is added to bromine
The bromine goes colourless
Why does bromine go colourless when an alkene is added to it
Alkenes are an unsaturated hydrocarbon so they have double bonds which can be broken to accept the bromine molecules
What properties do Short-chain hydrocarbons have
Less flammable compared to long chain molecules
It easily flows
has a low boiling point
What properties do long-chain hydro-carbons have
more flammable compared to short chain
viscous
high boiling point
What is the chemical formula for photosynthesis
6CO2 + 6H2O > C6H12O6 + 6O2
How did Carbon dioxide levels decrease during the early atmosphere
Water vapour condensed into oceans and seas
Carbon dioxide from the early atmosphere dissolved into the oceans and seas
thus decreasing the amount of carbon dioxide in the atmosphere
What is the greenhouse effect
the process in which greenhouse gases trap heat from the sun and reflect it back onto the Earth
What is causing the Greenhouse effect to be stronger
As we burn fossil fuels green house gases such as carbon dioxide are released into that atmosphere which causes the green house effect to be stronger
What are some examples of green house gases
Methane
Water vapour
Carbon dioxide
How is acid rain caused
When sulphur dioxide is dissolved in rainwater it causes it to be more acidic thus causing acid rain
What are some examples of atmospheric pollutants
carbon monoxide,
lead,
nitrogen oxides
particle pollution
sulphur oxides.
What is the Haber process
the process which allowed the synthetic production of fertilisers
How is wastewater treated
Step1: it is screened for any large debris such as sticks and stones
Step2: it is put into a settlement tank so all heavier solids sink to the bottom
step3:the waste water(effluent) is transferred to another tank where all the organic matter undergoes aerobic digestion
step4: the water though not safe for consumption can be released back into the environment
What are the advantages of recycling
Save finite resources
save energy
greenhouse gases shall reduce
What are the disadvantages of recycling
recycling items takes fuel and energy
materials such as metals can be difficult to sort and in turn recycle without expending a lot of energy
What is Phytomining
The process in wich plants are used to extract metal compounds from the ground
What is bioleaching
the process in which bacteria are used to extract metals from the ground
How is copper processed in bioleaching
bacteria are used to extract copper ions from low grade copper ores. During this process, bacteria convert copper compounds within ores into solution. These copper compound solutions are called the leachate
The copper in the leachate goes under a displacement reaction with iron
How are the metals in phytomining processed
the metal compounds build up in the leaves of the plant
the plants leaves are dried then turned into ash
ash dissolved in either hydrochloric or sulphuric acid and then displaced with iron using electrolysis
What are the stages of the Life cycle assessment
stage 1: extracting raw materials needed to make product and then processing them
Stage 2: manufacturing and packaging product
Stage 3: use of the product during its lifetime
stage 4: disposal at the end of a products life
What is Le chateliers principle
That if you change the conditions of a reversible reaction at equilibrium the system will try and counteract the change
In accordance with Le Chateliers principle what happens if you change the temperature
If you decrease the temperature the equilibrium will move in the exothermic direction to increase the temperature
If you increase the temperature the equilibrium will move in the endothermic direction of the reaction producing less heat
In accordance with Le Chateliers principle what happens if you change the pressure
Changing pressure only affects equilibriums with gases
If you increase the pressure the equilibrium will decrease the pressure by moving to an area with few gas molecules/ producing gas that has less molecules
If you decrease the pressure the equilibrium will increase the pressure by moving to an area with a high amount of gas molecules/ producing gas that has more molecules
In accordance with Le Chateliers principle what happens if you change the concentration
If you increase concentration of reactants more products are produced
if you decrease concentration of reactants the amount of products will also decrease
What is the formula for methane
CH4
What is the formula for Ethane
C2H6
What is the formula for Propane
C3H8
What is the formula for Butane
C4H10
In chemistry what is a pure substance
A substance that only contains one element or compound throughout
What does the boiling/melting point of a substance tell about a substance
A chemically pure substance will melt or boil at a specific temperature
impurities in sample will decrease the melting point and increase the melting range
impurities in sample will increase the boiling point
What is the test for Chlorine
Chlorine bleaches damp litmus paper
if you use blue litmus paper it may turn red as the chlorine solution is acidic
What is the test for oxygen
if you put glowing splint in test tube filled with oxygen the oxygen will relight the splint
What is the test for carbon dioxide
Bubbling carbon dioxide into a solution of calcium hydroxide (lime water) will cause it to go cloudy
What is the test for hydrogen
if you hold a burning splint over a test tube filled with hydrogen a squeaky pop will be heard
What is the mobile phase of Chromatography
Where the molecules can move. This is always a liquid or gas
What is the stationary phase of chromatography
Where the molecules cant move. This can be a solid or a really thick liquid
What is the stationary phase of chromatography
Where the molecules cant move. This can be a solid or a really thick liquid
What factors determine how quickly a chemical moves in chromatography
How quickly a chemical moves depends on which phase it spends the most time in
for example if a chemical spends more time in the mobile phase then it will move further through the stationary phase.
What are the steps of chromatography
Draw a line near the bottom of the filter paper with a pencil
add a spot of ink on the line and place the sheet in a beaker of solvent e.g. water
The solvent used depends on what’s being tested. some compounds dissolve well in water some don’t so in turn we may have to use ethanol
Make sure ink isn’t touching solvent
Place a lid on top of beaker to stop solvent from evaporating
The solvent seeps up the paper, carrying the ink with it
As the ink moves up the dyes in the ink will separate forming spots along the sheet representing each dye
insoluble dyes will stay at the base line
when the solvent reaches top of filter paper take paper out and leave it to dry
The end result is called a chromatogram
What is the RF value dependent on
The type of solvent used
How did Volcanic activity contribute to the growth of our atmosphere
Volcanic activity released nitrogen and carbon dioxide as well as water vapor while also releasing small amounts of methane and ammonia
How did the oceans, algae and green plants contribute to our atmosphere
Lots of carbon dioxide was dissolved into the oceans and after a series of reactions formed carbonate precipitates that formed the sediments on the seabed
Algae and green plants absorbed CO2 to carry out photosynthesis
How did algae and green plants contribute to our atmosphere
They carried out photosynthesis decreasing the amount of CO2 and increasing the amount of oxygen in the atmosphere.
How do greenhouse gases induce climate change
Green house gases don’t absorb the short wave radiation from the sun but instead the long wave radiation that gets reflected back off the earth
They green house gases then reflect that long wave radiation back onto Earth constantly
Since long wave radiation is thermal radiation it will heat up the Earth when its reflected back onto Earth
Thus global warming
What are the negatives of bioleaching
it produces toxic substances, including sulfuric acid, which damage the environment.
