Chemistry Flashcards
What are the properties of a solid?
- Particles are closely packed in regular structures with strong bonds.
- It is the state of matter with least energy.
- It has it’s own shape.
- Moves by vibration
What is a fuel?
A chemical store that combusts to realease energy.
Describe how particles are arranged in a solid:
- Particles held closely together
- Particles vibrate around fixed positions
- aoms in a regular formation
- little energy
- cannot be compressed
Describe how particles are arranged in a gas:
- Particles are very far apart
- Particles are separated and move freely
- Fill the space available
- Most energy of all states
- Particles move around alot
- Gas particles can be compressed
How do you separate an insoluable solid from a liquid?
Filtration.
Example of an alkali?
HYDROXIDE
OH
e.g. NaOH
What are the name of the salts made by hydrochloric acid (HCl)?
Chloride salts.
e.g. HCl + NaOH →NaCl + H20
Sulphuric acid = H2SO4
Makes sulphate salts.
e.g, H2SO4 + 2NaOH → NaSO4 + 2H20
Alkali + Acid =
Salt + Water
Acid + Metal =
Salt + Hydrogen
Acid + Carbonate =
Salt + Water + CO2
What do you see when you add a metal + acid?
- Effervescence
- Fizzes and whizzes around
- Metal disappears
What is thermal decomposition?
When heat causes a compund to break down.
HAPPENS TO CARBONATES.
CaCO3 ► HEAT ► CaO + CO2
How do you prevent rust?
Galvanise = add a more reactive metal coat
e.g. zinc added over iron.
Could also:
- paint to exclude oxygen
- cover in grease/oil
- cover in plastic
The key is to exclude oxygen
Describe how particles are arranged in a liquid:
- Particles held close together but can move freely
- more energy than a solid
- less energy than a gas
- can move freely
- will take the shape of its container
- cannot be compressed
What happens to particles when state changes from a solid to a liquid?
- Particles gain more energy
- Particles move around more
- Particles spread out
What is a chemical change?
- Bonds are made or broken
- The molecule/atom/compound is changed
- often irreversible
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What is a physical change?
- a change of state
- the molecule itself stays the same
- it is reversible
What is combustion?
- Fuel + Oxygen
- Releases energy
What is a physical property?
- Magnetic behaviour
- Strength
- Flexibility
- Conductivity
- Hard
- Rigid
- Compressible
- Dense
- Thermal conductor
- Electrical conductor
- Shiny / dull
- Transparent / translucent / opaque
- Absorbant
- Permeable
- Waterproof
How do you obtain coloured dyes?
Chromatography
How do you obtain a soluble solid from a liquid?
Distillation
What are some examples of bases?
Hydroxides - e.g. Sodium Hydroxide (NaOH)
Oxides - (Metal oxides) e.g. MgO
Carbonates - Calcium carbonate CaCO3
Nitric acid
- Makes NITRATE salts
- e.g. HNO3 + NaOH = NaNO3 + H2O
What is a compound?
- two or more element combined
What is a mixture?
- It contains two or more types of atom/molecul/compound
- e.g. Air, soil, concrete
How do you separte a mixture?
- Sieving
- Filtering
- Decanting
- Flotation
- Evaporation
- Distillatgion
- Chromatography
What is an alloy?
- A mixture of metals:
- Brass (Copper, Zinc)
- Bronze ( Copper, Tin)
- Steel ( Iron, Carbon, Nickel)
What are the properties of metallic elements?
- There are about 80 metallic elements
- Normally solid at room tempurature
- Strong
- Shiny
- Maleable
- Conduct heat and electricity
- Dense
- High melting points
- Some are magnetic
- Corrode
- React with air or water
What is the reactivity series?
- Potassium
- Aluminium
- Zinc
- Iron
- Copper
- Silver
- Tin
- Lead
- Gold
What metals were used in ancient times?
- Copper
- Silver
- Gold
What is a solution
- A mixture of a solid liquid or gas, and a liquid
What are the properties of non-metallic elements?
- There are about 20 of these
- Not stong
- Dull
- Brittle
- Not a good conductor of heat or electricity
- Not dense
- Low melting point
What are diamonds made of?
Carbon.
The strongest sustance known to man.
Where are diamonds mined.
Africa (Angola, Botswana, South Africa)
Asia (India, Russia, Indonesia)
North America (Canada, United States)
What is graphite?
A form of carbon (i.e. non metal)
Graphite conducts electricity
How are metal oxides formed?
When metal is combined chemically with oxygen.
What is neutralisation?
An acidic solution is neutralised by an appropriate amount of an alkali solution.
What indicators of acid/alkali are used?
Litmus paper:
Acid = Red / Alkali = Blue
Universal indicator:
0-14
Red -acid, Green = neutral, Purple = alkali
Why do metals tarnish?
Tarnish is normally caused by an oxide forming on the surface.
Oxidisation and reduction
Fe + CuO ► FeO + Cu
- Iron is more reactive than Copper
- Iron is oxidised
- Copper is reduced
What is displacement?
A more reactive metal displaces another from its salt
e.g. Iron + Copper Sulphate ► Iron Sulphate + Copper
How do you extract metals from their ore
- Decomposition
- Electrolisis
- Reduction
solvent & solute =
solution
As temperature goes up how does this affect solubility?
Solubility increases.
If a substance does not dissolve in water it could dissolve in what other liquids?
ethanol or propanone.
What metals are magnetic?
Tron
Cobalt
Nickel
Steel (iron + carbon)
What is the equation for respiration?
glucose + 02 ►ENERGY RELEASED►CO2 + H2O
What is the equation for photosynthesis?
CO2 + H2O ►LIGHT►sugar + O2