KS3 chemistry revison Flashcards
Define mixture
Where particles of different substances are together but not joined
Define solvent
The liquid
Define Solute
The soluble solid
Define solution
Where a solid has dissolved in a liquid
Define insoluble
A solid that cannot be dissolved
Define soluble
A solid that can be dissolved
What is filtration?
A process that removes insoluble solid from a liquid
What is crystallisation by evaporation?
A process that is used to separate a solute from a solvent (salt from saltwater)
What is distillation (evaporation followed by condensation)
A process that separates a pure solvent from a solution (water from saltwater)
What is chromatography
A process that individual solutes from a mixture of solutes in a solvent.
What is physical change and an example of it
When something changes state and is still reversible most of the time. An example of physical change is ice to water to team because it is reversible.
What is chemical change and an example of it
When something creates a new substance and then becomes irreversible most of the time. An example of a chemical change is burning wood as it cannot be changed back to wood after being ash.
When carbon burns it combines with oxygen to form the compound carbon dioxide. What is the word equation of this reaction.
Carbon+Oxygen –> Carbon dioxide
Magnesium+Oxygen –>
Magnesiumoxide
Copper+Oxygen –>
Copperoxide
What is the name of the reaction that one of the reactants is oxygen
Oxidation reactions
Sulphur+oxygen –>
Sulphur dioxide
Phosphorus+oxygen –>
Phosphorus dioxide
What is the symbol for carbon
C
What is the symbol for calcium
Ca
What is the symbol for cobalt
Co
What is the symbol for copper
Cu
What are the group 7 elements called
Halogens
Define corrosion
When a metal reacts with oxygen
Define rusting
The corrosion of iron
Ca+ CI2= CaCI2
Already balanced
Pb+Br2=Pb+2Br2
Pb+2Br2+PbBr4
AI+O2= AI2 O3
2AI+3O2=2AI O3
Ge+F2=GeF4
Ge+2F2=GeF4
What is the reactivity series of metals in order
Potassium, Sodium, Lithium, Calcium, Magnesium, Aluminium, Zinc, Iron, Tin, Lead, Copper, Mercury, Silver, Gold, Platinum
What is the way to remember the reactivity series of metals in order
Please stop loudly calling my alligator Zac in the Latin classroom my silly goat please
Potassium, Sodium, Lithium, Calcium, Magnesium, Aluminium, Zinc, Iron, Tin, Lead, Copper, Mercury, Silver, Gold, Platinum
What is an anomalous result
A result that is very different from the other recorded results
What is a repeatable result
A result that you get a similar result again after repeating the experiment at least once
What is a reproducible result
Where other people get a similar result after conducting the same experiment
What is the hydrogen gas test
Squeaky pop…
- Firstly you collect the gas
- Then get a lit splint and hold it over the gas
- If a squeaky pop is heard then the gas is hydrogen
How can you prevent rusting
You can do this by applying oil, using an alloy, apply a dry coating to protect from the rust.
What is the reaction for metal and water?
metal+water–>metal hydroxide+hydrogen
What happens when metals react with water?
Metal hydroxide and hydrogen are the products. How vigorous the reaction is, reflects how reactive the metal is.
What is the reaction of metals and acids?
metal+acid–>metal salt+hydrogen
What happens when metals react with acid?
If the metal is very unreactive then the reaction has very little effervesce whereas if they are reactive then the reaction
What are displacement reactions?
Displacement reactions involve a metal and a compound of a different metal. A more reactive metal displaces a less reactive metal from its compounds.
Why do displacement reactions happen?
The more reactive metal gradually disappears as it forms a solution. The less reactive metal coats the surface of the more reactive metal.
Iron chloride+Magnesium–>
Magnesium Chloride+Iron
Zinc Chloride+Copper–>
Zinc Chloride+Copper
What are the two methods of extracting metals?
Displacement reactions and electrolysis.
What is electrolysis?
The flow of an electrical current in a conducting solution or molten liquid which causes chemical changes.
How do we decide which method of metal extracting to use?
If the metal is higher on the reactivity series than carbon then electrolysis should be used. An example of this is Aluminium. If the metal is lower on the reactivity series than carbon then you should use displacement reactions.
What are catalysts?
They speed up the reaction but do not get used up (their mass stays the same)
Why are catalysts used?
They are used to save money in the economy because they use less money.
What is an example of a catalyst and what gases does it reduce?
Catalytic converters in cars. This also reduces pollution which is done by changing harmful gases such as carbon monoxide, nitrogen oxides and unburnt fuels into less harmful gases such as carbon dioxide, water, nitrogen.