2.1 Atoms And Reactions Flashcards
Relative Isotopic Mass
The mass of an atom of an isotope compared to one-twelfth of the mass of an atom of C-12 isotope
Amount of substance
Number of particles, measured in moles
Avagadro’s constant, Na
Number of particles per mole of a substance, 6.02 x10^23 mol^-1
Molar mass
The mass per mope of a substance in gmol^-1 = RFM
Mole
Amount of any substance with as many particles as there are C-atoms in exactly 12g of C-12 isotope,
Moles = Mass / RFM
Isotopes
Atoms of the same element with the same number of protons but different numbers of neutrons, and different masses
Acid
Proton donor - release H+ ions (protons) in solution, eg H2SO4, HCl, HNO3, CH3COOH (weaker)
Base
Proton acceptor - readily accepts H+ ions from acid in aq solution
Alkali
A soluble base that releases OH- ions in aq solution, eg NaOH, KOH, NH3
Neutralisation reaction ionic equation and observations
H+ (aq) + OH- (aq) –> H2O (l)
Metal dissolves, fizzing- CO2 (bubble through limewater cloudy to test), -H2 (lighted splint squeaky pop to test), temp rise and pH change?
Acid and carbonate forms…
Salt and carbon dioxide and water
Acid and metal oxide forms…
Salt and water
Acid and alkali forms…
Salt and water
Acid and metal forms…
Salt and hydrogen
Redox!
Salt
Produced when H+ ion of an acid is replaced by a METAL ion or another positive ion eg NH4+ ion
Hydrated
A crystalline compound containing water molecules
Anhydrous
A substance that contains no water molecules (the form without water)
Water of crystallisation
Water molecules that form an essential part of the crystalline structure of a compound
What do you need to work out empirical formula of hydrated compound?
Mass of anhydrous salt, and mass of WofC
Oxidation Number
A measure of number of electrons that an atom uses to bond with atoms of another element
Oxidation number rules
- -
Redox
Reaction where both oxidation and reduction occur
Oxidation
Loss of electrons, or increase in oxidation number
Reduction
Gain of electrons, or decrease in oxidation number