2.1.4 Acids and Experiments Flashcards
An acid…
releases H+ ions in aqueous solutions
A base…
accepts H+ ions from an acid
An alkali…
releases OH- ions
Strong acids…
completely dissociate when aqueous
Weak acids…
slightly dissociate when aqueous and form an equilibrium mixture
A salt is formed when…
the H+ ion of an acid is replaced by a metal ion or ammonium ion
Heating a crucible could be done to test…
- mass loss in thermal decomposition reactions
* mass gain when reacting Mg in O
Method for heating a crucible
1) weigh empty crucible and lid
2) add 2g of hydrated compound - weigh again
3) heat strongly for a few minutes using a bunsen burner
4) reweigh crucible
5) heat again and reweigh to reach a constant mass
Large amounts of solid should not be used in crucible reactions because…
the reaction is likely to be incomplete
small amounts of solid should not be used because…
weighing errors are likely
the crucible needs to be dry because…
a wet crucible would give an inaccurate result as the water would be lost during the reaction
Method for making a solution
1) weigh an empty weighing boat
2) add required amount of solid and reweigh
3) add distilled water and stir with a glass rod until solid dissolves
4) transfer to a 250cm^3 volumetric flask using a funnel and rinse the beaker and glass rod into the flask
5) add distilled water until reaching the mark on the flask, insert stopper and invert several times
