acid and alkali Flashcards
are acids and alkai’s on the same side of the ph scale
no, they are on opposite sides
what are acids
substances that form hydrogen ions (H+) when they dissolve in aqueous soutions
what are alkalis
substances that form hydroxide ions (OH-) when they dissolve in aqueous solutions
name a type of base
an alkali
what is the ph scale sued for
to measure how acididic or alkaline a substance is
why does mixing an acid and alkali create a neutral substance
- acids form hydrogen ions when they dissolve in water
- alkalis form hydroxide ions when they dissolve in water
- H+ and OH- ions combine to form H2O
- water is a neutral substance, so an acid an alkai neutralise each other
what does ionise mean
become ions
what is the strength of an acid determined by
how much it ionises in water
is the strength of an acid the same as the concentraction of an acid
NO
what does it mean strong acids are fully ionised in water
all of the acid molecules break up to form H+ ions
what are examples of strong acids
sulfric acid and nitric acid
what is the equation for hydrochloric aicd
HCL -> H+ + CL-
what does it mean by weak acids only partially ionise in watrr
not all of the acid molecules break up to form H+ ions
are most acids weak or strong acids
weak acids
what does the concentration of an acid mean
how many moles of H+ ions are in a unit volume
what does the strength of the acid mean
how much of the acid ionises in watrer
what ph do acids have
less than 7
the lower the number on the ph scale the stronger the…
acid
what do acids neutralise
alkali
what do acids react with to produce salt
hydrogen
what neutralises the acidic food that leaves the stomach
bile
why is it important that bile neutralises acidic food that leaves the stomach
enzymes in the small intestine operate optimally in alkali condiitons and could therefore become denatrued in the absensce of bile
what ph number is neautral
7
what ph do strong acids have
close to zero
what ph do alkali’s have
more than 7
what do ph do strong alkali have
a ph close to 14
why is the ionisation of a weak acid a reversible reaction
only a few of the acid particles release H+ ions so equllibrium lies to the left
if the ph goes down one, what happens to the concentration
increase by x10
name examples of weak acids
ethanoic, ciric and carbonic acid
if you have a large proportion of acid moleulces, what will they do to release H+ ions
dissociate
if you have a small propotopn of the acid moleucles, what do they have to do to release H+ ions
dissociate
name 5 kinds of indicators `
- universal indicator
- ph probe connected to a ph meter
- phenolpthalein
4.methyl orange - litmus
what colour does an alkali solution turn when phenolpthaline used
pink acid
what colour does an acidic solution turn when phenopthalein is used
colourless
what colour does an alkaline solution turn when methyl orange is used
yellow
what colour does an acidic solution turn when methyl orange ix used
red
what colour does an acidic solution turn when litmus colution is used
red
what colour does an alkaline solution turn when litmus solution used
blue
what colour does an acidic solution turn when blue litimus paper is used
red
what colour does an alkaline solution turn when blue litmus paper is used
blue
what colour does the acidic solution turn when red litimus paper is used
red
what colour does an alkaline solution turn when red litmus paper is used
blue
as ph decreases by one unit, what happens to the H+ concentration
increases by factor x10
what does it mean when an acid in solution, has a high conc of H+ ions
the solution is more acidic, therefore ph is lower
what does it mean if an alkali solution has a higher conc OH- ions
solution is more alkaline, thereofre higher ph
the stronger the acid, the greater the dissociation…
the more H+ ions released and the lower ph
how to react an acid and base to obstain a insouble salt
- pour dilute acid into a beaker
- leave the beaker to heat on bunsen
- add base into dilute acid
- do this until no more of the base will dissolve
- take it off the bunsen
- filter it using a funnel and filter paper
- put the excess into a water batj
- once crystals starts to from
- filter it using filter paper and a funnel
- leave it to dry
acid + metal oxide
salt and water
acid + metal carbonate
salt, water and carbon dioxide
acid + metal hydroxide
salt + water
acid + metal
salt and hydrogen gas
what does insoulbe mean
a substance can’t dissolve in watrr
what does soulubles mean
a substance can dissolve in water
are nitrates soulube arer insolube
soluble
are chlorides solube or insolube
solube, excpet for silver and lead chloride
are sulafates soluble
yes except lead barium and calcium sulfate
are cstbonsyrd snf hydroxides soluble or insoulbe
insouble, except sodoium potassium ammonia
are pottassium ammonia and sodium soluble or insouble
solubele
