Chapter 4 - Acids and REDOX Flashcards
all acids contain what?
hydrogen in their formulae
when dissolved in water, acids release ?
hydrogen ions as protons - H (^+)
strong acid def
releases all hydrogen atoms into solution as H plus ions and COMPLETELY DISSOCIATES in aqueous solutuion
weak acid def?
only releases a small proportion of its available H atoms into solution as H plus ions. PARTIALLY DISSOCIATES in aqueous sol
weak acid have ?
a forwards/ backwards arrow (equilibrium sign) which indicates that the forwards reaction is incomplete
most organic acids, like ethanoic acid are ____ acids
weak
a base…
neutralises an acid to form a salt
what is an alkali?
a base that dissolves in water realising hydroxide ions into the solution
how do strong acids containing more than one H atom behave?
strong acid for only one H atom
next H acts as weak acid
What is a titration?
a technique used to accurately measure the volume of one solution that reacts exactly with another solution
what can titrations be used for?
- finding the conc of a solution
- identification of unknown chemicals
- finding the purity of a substance
burette readings always have ___ decimal places
2 - with the last place being either 0 or 5
concordant results
are within 0.1cm (^3) of each other
acids are?
proton donors bc they donate H(+) ions to bases
ammonia is a ?
weak base and forms a weakly alkaline solution when dissolved in water
strength of acids - what is strength?
a measure of dissociation
a strong acid easily gives up ?
protons, but a weak acid does not easily give up protons
strong base definition
is fully ionic.
100% splits up into metal ions and hydroxide ions in solution
weak base definition
doesn’t convert fully into hydroxide ions in solution
in neutralisation, the h(+) ion is replaced by?
a metal ion or any other + ion
interesting cases - acidic salts?
- formed from polyprotic acids
e. g. salts of sulphuric acid
what is a polyprotic acid?
- an acid that dissociates more than once - it donates more than 1 proton
interesting cases - ammonium salts?
- formed when acids are neutralised by aqueous ammonia
- salts formed contain the NH four (+) ion
Explain how OH minus acts as a base?
the Oh minus ion accepts a proton
explain why Kcl can be referred to as a salt?
the H plus ion in Hcl has been replaced by a metal ion
Common acids and their uses?
Hcl - stomach acid
Sulphuric acid - car batteries
Nitric acid - fertiliser
Bases are _____, _______, ________
Oxides, hydroxides and carbonates of metals
When converting into ionic equations,
Discount unchanged ions as tgesd re spectator ions
2 H[^+] + 2 OH [^-]
-> 2H (two) 0
Solute definition
The solid that is being dissolved
Solvent definition
The liquid that the solute is dissolved in
Solution definition
A mixture of the solute and solvent
How many sig figures?
Usually 3sf but look at data and use smallest amount as if bigger no. Of sig figs, you’re saying your data is more accurate
Scaling equation?
Moles × (volume scaling to / volume we have)
oxidation can occur both in terms of ____ and ______
oxxygen, electrons
oxidation (oxygen)?
gain of oxygen
reduction (oxygen)?
loss of oxygen
oxidation (electrons)?
loss of electrons
reduction (electons)?
gain of electron s
OIL RIG
roman numerals are used to?
represent the oxidation state pf an element
espec. important when element has more than 1 possible oxidation no.
what can have more than one possible oxidation number?
- Transition elements
- Oxyanions - end in ATE, composed of an element and oxygen
- e.g. nitrate
what is a redox reaction?
a reaction where both oxidation and reduction are occurring in the same reaction
oxidation is an _____ in oxidation number
increase
reduction is a _____ in oxidation number
decrease
disproportionation reduction?
reactions where the same elements are both oxidised and reduced
oxidation rules - elements?
oxdiation state of element = 0
oxidation rules - monatomic ions?
have lost or gained electrons
oxidation rules - hydrogen?
is +1 except in hydrides
oxidation rules- bonds in a molecule between the same element?
IGNORE
oxidation rules - oxygen?
-2 except in peroxides (a compound containing two oxygen atoms bonded together in its molecule or as the anion O22−) and if bonded to fluorine
oxidation rules - which atom is negative?
the most electronegative (closest to fluorine)
the sum of all ON =?
0
