Acids (chemical changes) Flashcards
titration calculations
- underline in seperate colours
- calculate moles of one (divide by 1000 to get in dm^3)
-use molar ratio to find moles of the other - use formula to find concentration (divide by 1000 to get in dm^3)
- to find in g/dm^3, multiply mol/dm^3 by RFM of substance
equation linking moles,
concentration and volume
m=cv
why are alkali metals never reacted with acids
Alkali metals are too reactive and cannot be carried out safely
what are the conditions needed for a reaction between an acid and a metal
the metal must be more reactive than the hydrogen in the acid otherwise no reaction will take place
what forms when you react a metal with an acid
a salt and hydrogen
how do you obtain a sample of the salt
can be crystalised out of the solution by evapouration
what is a redox reaction
reaction between a metal and an acid
what happens in a redox reaction
metal atoms lose electrons and are oxidised
the hydrogen ions in the acid gain electrons and are reduced
OILRIG
Oxidation
Is
Loss
(of electrons)
Reduction
Is
Gain
(of electrons)
how to formulate ionic equations
- write out normal equation
- write out equation taking oxidation and reduction into account
- delete spectator ions
- write out equation
neutralisation equation
acid + base → salt + water
mixture
two or more substances not chemically combined together
differences between mixtures and compounds
- compounds have a fixed composition
- mixtures have no fixed composition
- compounds can only be separated by a chemical reaction
- mixtures can be separated more easily
- there are chemical bonds between atoms in a compound
- there are no chemical bonds between atoms in a mixture
methods of separating mixtures
- filtration
- distillation
- crystallisation
- chromatography
when would you use filtration
1 soluble, 1 insoluble
when would you use distillation
when you need to collect the solvent from crystallisation
when would you use crystallisation
to obtain pure salt
how is filtration carried out
poured into a conical flask via a filter funnel with filter paper
how is crystallisation carried out
by evapourating the water from the solution using a evapourating dish over a beaker of water over a bunsen burner
how is distillation carried out
using a condenser to collect pure water
