C1 Flashcards
law of conservation
total mass of reactants = total mass of products
nano-
Multiplies the unit by 10-9
Symbol is n
micro
Multiplies the unit by 10-6
Symbol is μ.
millli
Multiplies the unit by 10-3.
Symbol is m.
mega
Multiplies the unit by 10 to the power of 6.
This is equivalent to multiplying by 1000000.
Symbol is M.
giga
Multiplies the unit by 10 to the power of 9.
This is equivalent to multiplying by 1000000000.
Symbol is G.
tera
- Multiplies the unit by 10 to
the power of 12. - This is equivalent to
multiplying by
1000000000000. - Symbol is T.
test for hydrogen
- hold a lit splint to a test tube
with a gas - if the gas is hydrogen, then it
will make a squeaky pop
sound - it makes this sound bcs
hydrogen burns rapidly in the
presence of oxygen to give
H2O.
test for oxygen
*put a glowing splint into a test
tube containing a gas.
* if the gas is oxygen, the
splint will relight.
testing for carbon dioxide
*bubble through, or shake
carbon dioxide with, an
aqueous solution of calcium
hydroxide (also called lime
water).
* The solution will turn from
clear to cloudy.
oxidation
addition of oxygen
loss of electrons
reduction
loss of oxygen
gain of electrons
Magnesium + oxygen → magnesium oxide
2Mg + O2 → 2MgO
Iron oxide + carbon monoxide → iron + carbon dioxide
Fe2O3 + 3CO → 2Fe + 3CO2
conservation of energy
energy can be transferred usefully, stored or dissipated, but it cannot be created or destroyed
endothermic
*TAKES IN energy from surroundings
*normally shown through FALL in temperature
exothermic
*GIVES OUT energy to surroundings
*normally shown with RISE in temperature
examples of exothermic
combustion
neutralisation
oxidation
hand warmers
examples of endothermic
thermal decomposition
the reaction between citric acid and sodium bicarbonate
ice packs
sports injury packs
when squeezed forcefully, ammonium nitrate and water mix in the pack, resulting in instant cooling. the speed of this reaction makes these packs ideal for scenarios when ice is not immediately available.
2 requirements for a successful reactions
*reacting particles must collide
*collisions must take place with
sufficient energy (the
activation energy)
what is activation energy?
the MINIMUM amount of energy that reacting particles must have in order for a reaction to occur
What information is contained within reaction profile diagrams?
relative energies of reactants and products
activation energy
overall energy change
what do catalysts do in a reaction profile?
catalysts can increase reaction rates by lowering the activation energy
axes in reaction profile diagrams
y axis shows energy
x axis shows progress of reaction
bond breaking
requires energy so endothermic
bond making
releases energy so exothermic
energy change of a reaction
energy change = total bond energies of reactants−total bond energies of products
what is the unit for measuring bond energies?
kJ/mol
what is the greenhouse effect?
*The Sun gives out electromagnetic radiation. Some of this passes through the atmosphere and is absorbed by Earth - warming it up.
*The Earth emits long wavelength radiation which is absorbed by greenhouse gases in the atmosphere and then re-emitted in all directions - like back towards the Earth.
*The longwave radiation is infrared (thermal) radiation, so it makes Earth warmer than it should be.
what human activities have caused an increases concentration of greenhouse gases?
- landfill sites (methane)
- burning fossil fuels (carbon dioxide)
- deforestation (less carbon dioxide is being removed)
- agriculture (methane)
what are consequences of climate change
- melting of polar ice caps
- extreme meteorological
events like storms and
heatwaves - changing water availability
- changes in precipitation
combination of some or all of
these factors could hinder a
region’s ability to produce
food
how can individuals reduce carbon footprints?
Maximising the efficiency of their energy use.
Minimising their waste.
Using renewable energy sources.
how can governments reduce carbon footprints?
Emission-based taxes.
Emission caps.
what is potable water?
water safe for human consumption
what makes water potable?
low concentration of microbes
low concentration of dissolved salts
where can you get potable water from?
seawater
waste water
fresh water
how is potable water treated in the UK?
- collect the water (rainwater or fresh water source)
- filtration
- sterilisation
what is filtration?
passed through wire mesh to remove solid particles
what is sterilisation?
chlorine gas is added to kill harmful microorganisms.
how is potable water treated in saudi arabia?
seawater is used so they desalinate it with distillation or reverse osmosis
what is distillation?
boiling seawater creates steam, which then condenses to give pure water
what is reverse osmosis?
seawater is passed through a selective membrane that only allows water molecules through
disadvantages of chlorination
sometimes chlorine can react with compounds found in water and form potentially dangerous chemicals
- however the benefits outweigh the risks
advantages of chlorination
chlorination stops people from catching diseases found in contaminated water as it removes dangerous microbes such as typhoid and dysentery
how does chlorination work?
chlorine gas is bubbled through to kill harmful bacteria
how do you test for chlorine?
insert damp litmus paper into a test tube containing a gas.
if the gas is chlorine, the litmus paper will bleach and change colour from red to white.
limitations of the particle model
- forces between particles aren’t shown
- portrays particles as spherical when, in reality, they are not
- particle collisions aren’t as simple as the model suggests
- particles don’t ‘bounce off’ each other
early existence - volcanoes
- frequently erupted
- released carbon dioxide
latter existence - oceans
volcanoes also released nitrogen and water vapour which created oceans which removed lots of carbon dioxide from the atmosphere
what created oxygen in the earths atmosphere
*Algae = first photosynthetic organisms to evolve about 2.7 billion years ago
*photosynthesising plants began to evolve which led to lots of oxygen
* a threshold concentration of oxygen was reached which allowed more complex life forms to evolve (animals)
decrease in carbon dioxide
oceans
marine animals
photosynthesis
incomplete combustion
- when fuel is burned in lack of oxygen
-produces carbon monoxide and soot
complete combustion
- reactions where a fuel combines with oxygen
- Fuel + O2 → CO2 + H2O
dangers of nitrogen oxide
- inhalation causes respiratory
problems - nitric acid is a major
component of acid rain
dangers of sulfuric acid
- inhalation causes respiratory
problems - sulfuric acid is a major
component of acid rain
where do atmospheric pollutants come from?
burning fossil fuels
what are examples of atmospheric pollutants?
carbon monoxide
sulfuric dioxide
nitrogen oxide
particulates
