Acids, Bases and Salts Flashcards
what is an indicator?
a substance that is one colour in acids and another in alkalis
what is UI made up of?
a mixture of several different indicators
what does litmus solution turn in different pHs?
acid - red
neutral - purple
alkaline - blue
what does red litmus paper turn in different pHs?
acid - red
neutral - red (stayed the same colour as paper)
alkaline -blue
what does blue litmus paper turn in different pHs?
acid - red
neutral - blue (stayed the same colour as paper)
alkaline - blue
what does phenolphthalein turn in different pHs?
acid - colourless
neutral - colourless
alkaline - magenta pink
what does methyl orange turn in different pHs?
acid - red
neutral - orange
alkaline -yellow
what does UI turn in different pHs?
acid - red
neutral - green
alkaline - purple
what is red litmus paper used to test for an why?
alkalines as it turns blue
what is blue litmus paper used to test for and why
acids as it turns red
what ion causes acidity?
hydrogen ion H+
what does the pH scale measure?
the concentration of H+
what type of scale is the pH scale?
logarithmic
how much concentrated in H+ is ph 1 than ph 3?
100x
what does pH stand for?
potenz (power in german) and H+
what is the formula for phosphoric acid and the negative ion charge?
H3 PO4 and 3-
what is the formula for ethanoic acid and the negative ion charge?
CH3COO H and 1-
what is the formula for carbonic acid and the negative ion charge?
H2 CO3 and 2-
how did the HCL (gas) dissolved in water react ?
UI - red
effervsence with all compounds
is electrially conductive
how did the HCL (gas) dissolved in methylbenzene react?
UI - green
NVS
No electrical conductivity
what hapnes to the HCL when dissolved in solvents?
it separates the H+ and the Cl- (as it is an acid)
what is a Arrhenius acid?
and acid that dissolves in water to form H+ ions
what does dissociate mean?
refers to how many acid molecules have been split apart into ions
what does concentrated and dilute acids refer to?
refers to the amount of acid molecules dissolved in a certain amount of water
what does strong and weak acids refer to?
refers to how many acid molecules have dissociated into ions
examples of strong acids
HCL
HNO3
H2SO4
example of weak acid
ethanoic acid (CH3COOH)
what symbol do you use to show an acid is weak?
⇌ = reversible reaction and so not fully complete
what is the difference between the reactivity of strong and weak acids?
S.A are more reactive as they have fully dissociated acid molecules an so relatively has more H+ ions than W.A
what is a base?
substances that can neutralise acids
alkalis Vs bases
Alkalis - soluble bases (sub-group)
what type of metal compounds are bases?
metal oxides and hydroxides
what ion causes alkalinity?
OH- ions
examples of strong alkalis
sodium and potassium hydroxide
example of weak alkali
ammonia
metal + acid →
salt + hydrogen
metal + H+ → metal + H2
metal oxide + acid →
salt + water
2H+ + O2- → H2O
metal hydroxide + acid →
salt + water
H+ + OH- → H2O
metal carbonate + acid
salt + water + carbon dioxide
2H+ + CO3 2- → CO2 + H2O
ammonia + acid →
ammonium salt
H+ NH3 → NH4 1+
what causes neutralisation?
when the H+ from acid and OH- from alkali combine to form H2O
what experiment can be done to monitor the pH in a reaction?
how much vinegar and water is used?
how much lime is added each time?
when does the spike in pH happen?
- calcium hydroxide and ethanoic acid (lime and vinegar)
- 20ml each
- 0.1g
- at 0.9g of lime
calcium hydroxide + ethanoic acid →
calcium ethanoate + water
when would you use the excess base method?
to make a soluble salt out of an insoluble base and acid
when would you use in titration
to make a soluble salt from a soluble base and an acid
when would you use precipitation?
to make an insoluble salt using two soluble salts
usually what substances are used in excess base method?
a metal oxide + acid
usually what substances are used in titration method?
sodium or potassium hydroxide / ammonia + acid
usually what substances are used in precipitation method?
_______ nitrate + sodium _______
