Chemistry paper 1 Flashcards
Definition of a compound
Two or more elements which are chemically combined in fixed proportions.
Describe Thomson model of the atom.
A positive charge with a spherical shape with embedded electrons.The plum pudding model.
Describe John Dalton’s theory of the atom.
Solid spheres different spheres made different elements.
what did Ernest Rutherford and Ernest Marsden do to prove the PPM wrong?
Fire alpha particles at a sheet of gold.Some were deflected instead of all of them passing straight through.
Describe Ernest Rutherford theory of the atom.
Tiny positive charge (where most of the mass is concentrated) at the centre surrounded by electrons(Mostly empty space).The nuclear model.
What did Neils bhor suggest to the Nuclear model of the atom and why?
Electrons orbit in fixed positions (shells)
Because if they weren’t they would be attracted to the nucleus and collapse.
who discovered the existence of neutral particles.
James Chadwick
List three properties for G1 elements.
- One outer electron
- Low boiling and melting point decrease as you go down the group
- Become more reactive down the group
what are the G! elements known as?
Alkali metals
What is formed with a G1 element and water?
Alkali metal + water -> Metal hydroxide + hydrogen.
What is formed when G1 elements react with non-metals?
Ionic compounds
What are G7 elements known as ?
Halogens
What do the atoms in the halogens consist of?
Molecules
What happens to the reactivity of G7 elements and why?
Reactivity decreases as you go down because harder to gain electrons when further from the nucleus.
What do Halogens form when reacting with metals?
Ionic salts
what are group 0 elements known as ?
Noble gases
What is the reactivity of G0 elements?why?
Very unreactive because they have a full outer shell of electrons.
What does the change of state depend on?
Amount of energy needed to overcome forces of attraction between particles
What type of attraction does an ionic bond have
electrostatic between negative and positive ions
Define delocalised.
Electrons are not bound to one atom
What type of attraction does a metallic bond have?
Electrostatic forces between positive ions and electrons
List properties of a metal
High melting and boiling.
Good conductors.
Ductile.
Malleable.
what happens as simple molecular forces get bigger and why?
Bp and Mp incr. molecules get bigger so more inter molecular forces so more energy needed to break the bonds.
Describe structure of diamond
Carbon atoms form four strong covalent bonds.
Rigid giant covalent structure.(very hard)
Describe the structure of graphite.
Each carbon atoms form three covalent bonds
Makes layers of hexagons.
Layers are held together weakly because no covalent bonds.ifm
Layers slide over each other making it soft and slippery.
Delocalised electrons make it a good conductor
Describe the structure of graphene
Sheet of carbon atoms arranged in a hexagon. one atom thick Covalent bonds make it strong. Is very light conduct electricity
What is a fullerene. Talk about it’s structure.
Molecules of carbon.Shaped liked closed tubes or hollow balls can be formed from hexagons but other rings as well.
Name three uses of fullerenes.
Drug delivery.
catalyst.
Lubricants.
The mnemonic for the reactivity series.
Philip Scofield Loves Calling Me a Crazy Zombie. I Hate Cats.
Potassium. Sodium. Lithium. Calcium. Magnesium. Carbon. Zinc. Iron. Hydrogen. Copper.
Name 4 acids and their pH.
Car battery/stomach acid-1
Vinegar, lemon juice-3
Acid rain-4
Normal rain-5
The word equation for neutralisation
acid + base -> salt + water
what ions do acids or alkali for in water
acid-H+
alkali-OH-
what is the difference between weak and strong acids?
weak acids partially ionise in water
strong acids completely ionise in aqueous solutions
what position does the equilibrium lie on in the ionisation of a reversible reaction and why?
Left because only a few acid particles release H+ ions.
name 3 bases.Which one produces co2?
metal oxide,
hydroxide,
carbonate-co2
why should electrodes be made of inert material?
so they don’t react with the electrolyte
what is used to lower the melting point of aluminium oxide?why?
cryolite because it reduces costs because high boiling points mean lots of energy and that is expensive
what is produced at the cathode of electrolysis of aq solout.
- hydrogen if metal forms element more reactive that H
- pure metal formed around cathode if less reactive than hydrogen
what is produced at the anode of electrolysis of aq solout
- if OH- and halide ions present then cl,br or io will form
- if no halide ions present then oxygen and water will be produced
the half equation for if no halide ions are present
4OH–>o2+2h^2,o+4e