acids and redox Flashcards
list the names/formulae of the common acids
hydrochloric HCl
sulfuric H2SO4
nitric HNO3
ethanoic CH3COOH
list the names/formulae of the common alkalis
sodium hydroxide NaOH
potassium hydroxide KOH
ammonia NH3
define strong acid
an acid that dissociates completely in a solution
define weak acid
an acid that partially dissociates in a solution
what is a neutralisation reaction?
a chemical reaction in which an acid and a base react together to produce a salt
acid + metal = ?
salt + hydrogen
acid + metal oxide/hydroxide = ?
salt + water
acid + metal carbonate = ?
salt + water + carbon dioxide
how do you prepare a standard solution?
- weigh the solid
- dissolve solid in beaker using distilled water
- transfer solution to volumetric flask and rinse beaker with distilled water
- fill the flask to the graduation line with distilled water- so that the bottom of the meniscus lines up exactly with the mark (view at eye level)
- insert the stopper and invert the volumetric flask several times to mix the solution thoroughly
how do you convert between mol dm-3 and g dm -3?
concentration (mol dm3) = concentration (g dm3) / molar mass
what are the key stages in titration calculations?
- work out the amount in mol of the solution of known concentration and volume
- use the equation to work out the amount in mol of the other solution (using molar ratio)
- work out the unknown concentration of that solution using the moles and the volume
what is a standard solution?
a solution of a known concentration
acid + alkali = ?
salt + water
what are the oxidation number rules for pure elements?
oxidation number = 0
as any bonding is to atoms of the same element so there is no difference in electronegativity
what are the oxidation number rules for simple ions e.g. Na+, Mg2+, Cl- ?
the oxidation number matches the charge of the ion (Na+ = +1, Mg2+ = +2, Cl- = -1)
what is the oxidation number rule for fluorine?
oxidation number = -1
what are the oxidation number rules for oxygen?
oxidation number = -2
oxidation number in peroxides = -1
oxidation number when bonded to Fluorine = +2 (as fluorine is more electronegative)
what are the oxidation number rules for hydrogen?
oxidation number = +1
oxidation number in metal hydrides = -1
what are the oxidation number rules for atoms in compounds and ions?
sum of oxidation numbers = overall charge
how do you work out oxidation number in a compound/ion?
sum of oxidation numbers = overall charge so use the oxidation number rules to find the known oxidation number, then use this to work out the unknown.
how are Roman numerals used in systematic naming?
iron(III) represents Fe3+ with oxidation number +3
iron(II) represents Fe2+ with oxidation number +2
how do you work out a formula using oxidation number e.g nitrate(III)?
NO2-, nitrate (III)
if oxygen is -2 and there are two of them, then the total charge for oxygen is -4. as NO2- has a 1- charge, nitrogen must be +3, so it is called nitrate(III)
define oxidation in. terms of electron transfer
oxidation is loss of electrons (OIL)
define reduction in terms of electron transfer
reduction is gain of electrons (RIG)
