- Created by: bobby
- Created on: 31-12-09 17:27
Mass Charge Location
- Proton 1 +1 Nucleus
- Neutron 1 0 Nucleus
- Electron 1/2000 -1 Orbiting Nucleus
The Mass Number = The Top Number
The Atomic Number = The Bottom Number
Isotopes are different atomic forms of the same elements, which have the SAME number of PROTONS
(but a DIFFERENT number of NEUTRONS)
Ions are electrically charged particles formed when atoms lose or gain electrons.
Metal atoms form positive ions,
non-metal atoms form negative ions.
METAL ATOMS LOSE ELECTRONS.
NON METAL ATOMS GAIN ELECTRONS.
Ionic compounds have high melting and boiling points.
Sharing Elections = Covalent Bonding
Swapping Electrons = Ionic Bonding
A Covalent bond is a strong bond between two non-metal atoms.
It consists of a SHARED pair of electrons
Ar = Relative Atomic Mass (The Mass Number)
Mr = Relative Formula Mass (The sum of all the Ar's of a compound)
Ar x No. of atoms (of the element)
Percentage of an = -------------------------------------------------------------- x100
element in a compound Mr (of the whole compound)
Empirical Formula - Phosphorous Oxygen
1. Write the mass given 62g 48g
2. Mass ÷ Ar 62÷31=2 48÷16=3
3. Divide both numbers by
the smallest number 2÷2=1 3÷2=1.5
4. The ratio becomes the
Calculating Mass in Reactions
60g of Mg reacts to give how much MgO?
1. Write the balanced equation 2Mg + 0₂ --> 2MgO
2. Work out Ar & Mr 48 80
48g of Mg reacts to make 80g of MgO
3. Divide amount (48) 1g of Mg reacts to make 1.67g of MgO
4. Multiply by amount you want (60) 60g of Mg reacts to make 100.2g of MgO
Rate of Reaction
Rate of reaction depends upon:
Size of particles
Speed of a reaction
There are 3 ways to measure the speed of a reaction:
- Change in mass
- Volume of gas given off
- Rate of reaction = amount of product formed ÷ Time
Exo and Endo
EXOTHERMIC REACTIONS give out heat
ENDOTHERMIC REACTIONS take heat in
Some examples of EXOTHERMIC REACTIONS are:
- Neutralisation reactions between acids and alkalis
- The reaction between water and calcium oxide
Some examples of ENDOTHERMIC REACTIONS are:
- The reaction between ethanoic acid and sodium carbonate
- the thermal decomposition of calcium carbonate in a blast furnace
A reversible reaction is where the products of a reaction can themselves react to reproduce the original reactants.
The Haber Process
Hydrogen and Nitrogen are, at high pressure (200 Atmospheres), passed over an Iron catalyst at 450°C. Some of the Hydrogen and Nitrogen combine to form Ammonia (2NH₃), this ammonia is collected and the remaining Hydrogen and Nitrogen are re-used.
The forward reaction which makes ammonia is EXOTHERMIC.
Therefore the Yield is much better at Lower temperatures.
Haber Process = Low Temperature and High Pressure
Ammonia is used to make fertilisers, explosives, dyes, househoold cleaners and nylon.
Electrolysis of Copper
The electrical supply pulls electrons off at the anode and the copper goes into the solution as Cu²⁺ ions where they are offered electrons at the cathode, pure copper is then made at the cathode whilst all the impurities drop to the bottom.
+ve Ions = Cations
-ve Ions = Anions
Percentage Yield = -------------------------------------------- x100