Key Area 4: Acids and Bases Flashcards
The pH scale
runs from below 0 to above 14
A neutral solution has
equal concentrations of H+ (aq) and OH - (aq) ions
The symbol = with the arrows means
a reaction is reversable
Bases
Alkalis (metal hydroxides)
metal oxides
metal carbonates
All acids contain
hydrgoen ions H+
All alkalis contain
Hydroxide ions OH-
If you dilute an acid by a factor of 10
the pH goes up by 1
If you dilute an alkali by a factor of 10
the pH goes down by 1
Conducting liquids and solutions are called
Electrolytes (conducting liquid)
The three stages of a method
Neutralisation
Filtration
Evaporation (crystallisation)
Base equation
Base + Acid —> Salt + Water
Carbonate equation
Acid + Metal carbonate –> Salt + Carbon Dioxie + water
Carbonates of group 1 are soluble
therefore alkalis
A good indicator will produce a
sudden sharp colour change
Strong acids
pH less than 2
weak acids
pH 3-6
neutral
pH 7
strong alkali
pH 12 and above
pH can only be measured if?
water is present
the exact point where neutralisation occurs?
end-point
Acid
Anything with a pH less than 7
Base
Neutralises acids, resulting in the pH of the acid increasing towards 7, and water being produced
Which type of oxides dissolve in water to form an acidic solution?
Non-métal oxides
Which type of oxides dissolve in water to form a neutral solution?
None
Which type of oxides dissolve in water to form a alkali solution?
Metal oxides
Name three metal bases
Metal oxides
Metal carbonates
Metal hydroxides
Metal oxide + acid —>
Salt + water
Metal hydroxide + acid —>
Salt + water
Metal carbonate + acid —>
Salt + water + carbon dioxide
What are spectator ions?
Ions that do not take part in reaction, remain unchanged
Acidic solutions have a higher concentration of?
Hydrogen ions than hydroxide ions, and have a pH below 7
Alkaline solutions have a higher concentration of?
Hydroxide ions than hydrogen ions, and have a pH above 7
