Chapter 4: Acids and redox Flashcards
what is the main characteristic of an acid
acids donate H+(aq) in aqueous solution
what does a strong acid do
strong acid dissociates fully there H+ ions
what is a monoprotic acid
acid that breaks up and dissociates to form one proton
what is a diprotic acid
acid that breaks up and dissociates to form two proton
what is a tripotic acid
acid that breaks up and dissociates to form three protons
what does concentrated and dilute refer to in acids
refers to how much acid there is in a set volume
what is the pH scale in terms of mathematical formula
pH = -log[H+]
what is a weak acid
acid that only partially dissociates in aqueous solution
what is a Base
substance that neutralises an acid and accepts H+ ions to form water and salt
what is an alkali
a base that dissolves to form OH-(aq) ions
what is the general neutralisation formula
Acid + base –> Salt + Water + (Carbon Dioxide)
what do titrations always need
Aqueous solution
what is a spectator ion
it is an ion that during the reaction nothing happens to
what does an ionic equation do
get rid of spectator ion and show what is actually happening during the reaction
what is the first step for writing an ionic equation
write a ‘normal’ balanced equation
what is the second step for writing an ionic equation
ionic compounds in aqueous solution will split into separate hydrated ions which react independently
what is the third step for writing an ionic equation
look for the spectator ions and remove from the equation
what are the two things you do to spot the spectator ions
are they in an aqueous solution
are they unchanged
if yes to both they are spectator ions
what is the fourth step for writing an ionic equation
write out the remaining ionic equation with state symbols
what is quantitative analysis
all about measuring amounts then analyse and evaluate date
what is volumetric analysis
involves using volumes
what is the percentage purity formula
(mass of pure substance / mass of impure sample) x 100
what is a REDOX reaction
a reaction where both oxidisation and reduction happen
what is an ionic half equation
where you split an ionic equation in half to show what is happening to each ion
what is an Oxidising Agent
A chemical species that causes something else to be oxidised and is itself reduced
what is a Reducing Agent
A chemical species that causes something else to be reduced and is itself oxidised
what are Oxidation Numbers
Theoretical numbers of electrons involved in bonding of an atom to a separate element, whether ionic or covalent
what is the element oxidation number
any element in its elemental form has an oxidation number of 0
what is the simple ion oxidation number rule
in a simple ion the oxidation number is equal to the charge
what does an increase in the oxidation number mean
the element is being oxidised
what does a decrease in the oxidation number mean
the element is being reduced
what is the compound oxidation number rule
in a compound the total oxidation number of each atom add up to 0
what is the complex ion oxidation number rule
in a complex ion the oxidation numbers of all the atoms add up to the remaining charge
what do Roman numerals in Chemistry represent
Roman numerals show the oxidation number where an element can have more than one oxidation state
what are the three special cases for oxidation states
> Hydrogen in metal hydrides
Oxygen in peroxides
Halogens can vary
explain how metal hydrides are special cases for oxidation states
Hydrogen has a negative oxidation number
e.g. NaH H has an oxidation state of -1
explain how peroxides are special cases for oxidation states
Oxygen has an oxidation state of -1
e.g. H2O2 Oxygen has an oxidation number of -1
explain how halogens are special cases for oxidation states
Halogen can have varying oxidation state from usual -1
e.g. HClO Cl has an oxidation state of +1
what is disproportionation
where an element is both oxidised and reduced in the same reaction
