Acids, bases and oxides Flashcards
metal vs non-metal oxides in terms of acidity
Metallic oxides are usually BASIC
non-metallic oxides are usually ACIDIC (or neutral)
what is the pH scale? how do you read it?
A measure how of acidic or alkaline a solution is.
- On a scale of 1-14
- 7 being neutral
the lower the number the more acidic (higher concentration of H+ ions)
the higher the number the more basic it is (higher concentration of OH- ions)
What is an acid?
a substance that generate H+ ions (or protons) in aqueous solutions
- acids are proton donors
What is a base?
a substance that generate OH-, hydroxide ions in aqueous solutions
- bases are generally metal oxides or hydroxides
- soluble base = alkali
- bases are proton accepters
pH indicator (litmus paper)
can be either blue or red.
Acids should remain/change to litmus paper red
Bases should remain/change to litmus paper blue (insoluble bases will not affect litmus paper)
pH indicator (Methyl orange indicator)
Acidic = orange
Neutral/alkaline/base = yellow
What are neutralisation reactions?
A reaction between an acid and a base.
- Acid + base(and alkali) = salt + water
The acid reactions to know are..
- Acid + metal
- Acid + metal –> salt + hydrogen - Acid + base
- Acid + base –> salt + water - Acid + carbonate
- Acid + carbonate –> salt + water + carbon dioxide-
The base reactions to know are…
- Acid + base
- Acid + base –> salt + water - Base + ammonium salt
- base + ammonium salt –> salt + ammoNIA + water
What are strong/weak acids?
High concentration of H+ (ions), resulting in a very low pH.
Weak acids release small amounts of H+ (ions) because molecules are only partially ionised in aqueous solutions.
What are strong/weak bases?
High concentration of OH- (ions), resulting in a very high pH.
Weak bases release small amounts of OH- (ions) because molecules are only partially ionised in aqueous solutions.
What are amphoteric oxides?
that can react with both acids and bases to release salt + water
(zinc oxide/hydroxide, aluminium oxide/hydroxide)
zinc oxide/hydroxide, aluminium oxide/hydroxide)
if they react with an acid they act as a base, if they react with a base they act as an acid (amphoteric)
they will release salt + water (acid + base –> salt + water)
Acid + metal?
salt + hydrogen
Acid + base?
salt + water
