chemistry unit 1 summary
- Created by: Asal
- Created on: 22-12-12 22:22
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- Chemistry
- first ionisation energy
- The energy required to remove an electron from each atom in one mole of gaseous atoms
- Mg (g) -> Mg+ + e-
- van der waals' forces
- uneven distribution of electrons produces an instantaneous dipole the dipole induces dipoles in neighbouring molecules, dipoles attract one another
- bond angles
- electron pairs repel lone pairs repel more than bonded pairs
- 2 bonds linear 3 bonds trigonal 4 bonds tetrahedral 6 bonds octahedral
- - 2.5 degrees for each lone pair
- silicon dioxide bent one lone pair 118 degrees water bent two lone pairs 104.5 degrees
- intermolecular forces- permanent dipole-dipole interactions van der waals' forces
- hydrogen bonds ice is less dense than water ice forms an open lattice of hydrogen bonds
- h bonds hold water molecules together tightly at the surface means water has a high surface tension
- mole- avogadro constant when a substance has as many particles as there are carbon atoms in 12 grams of carbon 12.
- thermal decomposition- using heat to break a compound into at least two substances
- Ag+ (aq) + Cl- (aq) -> AgCl
- Add silver nitrate- precipitation reaction precipitate forms, chloride ions present white precipitate forms iodide ions present yellow precipitate forms bromide ions present cream precipitate forms
- disproportionation reaction- when the same element is both oxidised and reduced
- redox reaction- a reaction in which both oxidation and reduction takes place
- electronegativity the ability of an atom to attract the bonded pair of electrons in a covalent bond
- a non-polar molecule is symmetrical so all polar bonds cancel each other out
- metallic bonding- electrostatic attraction between metal ions and delocalised electrons
- ionic bonding- electrostatic attraction between oppositely charged ions
- covalent bonding the sharing of a pair of electrons
- dative covalent bonding- the two electrons in a covalent bond are provided by one atom only
- Oxidation numbers hydrogen 1+ oxygen 2- chlorine 1- ion charge on ion unbonded element 0
- salt- when the h+ ion on an acid is replaced by a metal ion or an NH4+ ion
- acid proton donor
- base proton acceptor
- I2+ Cl2-> 2Cl- + I2 displacement reaction
- mole n=m/M
- gas volume v=n x 24 in dm3 or 24000 in cm3
- concentration n=c x v in dm3 or v/1000 in cm3
- in titration c= n x 1000/ v
- mole n=m/M
- hydrated- with water
- anhydrous without water
- water of crystallisation the water that forms an important part of the crystalline structure
- first ionisation energy
- first ionisation energy
- The energy required to remove an electron from each atom in one mole of gaseous atoms
- Mg (g) -> Mg+ + e-
- van der waals' forces
- uneven distribution of electrons produces an instantaneous dipole the dipole induces dipoles in neighbouring molecules, dipoles attract one another
- hydrogen bonds ice is less dense than water ice forms an open lattice of hydrogen bonds
- h bonds hold water molecules together tightly at the surface means water has a high surface tension
- a non-polar molecule is symmetrical so all polar bonds cancel each other out
- dative covalent bonding- the two electrons in a covalent bond are provided by one atom only
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