CC8 Acids Essential Flashcards
What does soluble mean? What does insoluble mean?
Dissolves in water. Does not dissolve in water
Define acid in terms of pH
A substance with a pH of less than 7
Define acids in terms of ions
A substance which releases H⁺ ions in solution
What is a neutral solution?
A solution with a pH of 7. Water is an example.
How do you measure pH?
(2 ways)
With an indicator or pH probe.
Which ions are always present in a solution of an alkali?
hydroxide ions - OH⁻
What is a neutralisation reaction?
A reaction involving an acid that results in a neutral solution.
How do you make a soluble salt from an acid?
React the acid with a base. E.g. to make copper sulphate react copper oxide with sulphuric acid
If a salt is in solution, how do you extract it as a solid?
Allow the water to evaporate off and it will leave the salt behind as a solid.
What is a strong acid?
An acid which completely splits up into its ions in water. E.g. when HCl is in water all the HCl molecules split up into H⁺ and Cl⁻.
What is a weak acid?
An acid which will have some molecules which do not split up into their ions. E.g. in ethanoic acid only some of the molecules will have split up into the ethanoate ion and H⁺ ions.
What is the relationship between an acid of pH2 and an acid of pH 3?
pH 2 is 10 times more hydrogen ions than pH 3
What is a concentrated acid?
An acid where there are lots of acid particles in the water.
What is a dilute acid?
An acid where there are fewer acid particles in the water.
How can hydrogen be tested for?
Makes a squeaky pop when a lit splint is placed in it
How can carbon dioxide be tested for?
Bubble through limewater, turns it milky (cloudy)
What colour is litmus in acid and alkali?
Acid – red, alkali – blue
What colour is methyl orange in acid and alkali?
Acid – red, alkali – yellow
What colour is phenolphthalein in acid and alkali?
Acid – colourless, alkali – pink
How do you prepare a sample of a soluble salt from a base and an acid?
Neutralisation with excess base, filtration, crystallisation
How do you prepare a sample of a soluble salt from an acid and an alkali?
Titration, repeat titration without indicator, crystallisation
How do you prepare a sample of an insoluble salt from two solutions
Combine, filtration.
