acids and bases Flashcards
what are alkalis?
bases that will dissolve in water
what is used to test acids and alkalis?
litmus
what do acids and alkalis turn litmus?
acids- red
alkalis- blue
what happens when an alkali and alkalis meet?
they neutralise each other
what does the pH show?
how acidic or alkaline a substance is
what does a pH of 0 mean?
shows a strong acid
what does a pH of 14 mean?
a strong alkali
what is a neutral pH?
7
finish this sentence… acids have a pH of
less than 7
finish this sentence… alkalis have a pH of
more than 7
when is a base and alkali?
when it dissolves in water
what is an alkali?`
just a soluble base
give an example of a base that in not an alkali?
copper oxide
what are the most common bases?
metal oxides and metal hydroxides
what is the equation for the reaction of an acid and base?
acid+base—salt+water
what do all acidic solutions contain?
hydrogen ions
what is the unit for this?
H+
what are indicators?
substances which change colour when pH changes
when does an indicator such as litmus change colour?
suddenly at one pH value only
when do indicators such as universal indicator change?
gradually over a range of different pH values
what does an acid solution contain?
hydrogen ions, h+
what are hydrogen ions responsible for?
the reactions of an acid
what does an alkali solution contain?
hydrogen ions, OH-
what happens when an acid neutralises an alkali?
the hydrogen ions react with the hydroxide to make water
what is the equation for this?
H+OH- —- H2O
when a pH = 0 what does this mean?
it is very acidic
when a pH is 14 what does this mean?
it is very alkaline
explain what happens when an acid rises in the pH scale?
the ph at the start is low
the ph rises as the alkali neutralises the acid
neutral
when more alkali is added the ph rises to 7
explain what happens when an alkaline falls in the pH scale?
the ph is high
the ph falls as the acid neutralises the alkali
neutral
when more acid is added the ph falls below 7
what does an universal indicator show?
how acidic something is
what is universal indicator?
a mixture of indicators, each one changing at a different ph
what are the equations for metal oxides and hydroxides?
acid+oxide—salt+water
acid+hydroxide—salt+water
what is the equation for the reaction between acid +carbonate?
acid + carbonate — salt + water + carbon dioxide
what is salt made from?
part of a base and part of an acid
what is made when sodium hydroxide reacts with hydrochloric acid?
sodium chloride is formed
where do nitrates come from?chlorides?sulfates?phosphates?
nitric acid
hydrochloric acid
sulfuric acid
phosphoric acid
