Chapter 4 - Acids and Redox Flashcards
What is an acid?
Releases H+ ions as protons in aqueous solution
Proton donors
What is an alkali?
An alkali releases OH- ions in aq solution
Water-soluble base
What are the common acids?
HCl
H2SO4
HNO3
CH3COOH
What are the common bases?
NaOH
KOH
NH3
What is a strong acid?
An acid that fully dissociates in aq solution
What is a weak acid?
An acid that partially dissociates in aq solution
What is meant by neutralisation?
The reaction of an acid with a base to form water
What are the products of an acid + carbonate?
Carbon dioxide + water + salt
What are the products of an acid + metal oxide?
Salt + water
What is a titration?
A practical method where a standard solution is reacted with a solution of unknown concentration in order to determine the concentration of this solution
How do we prepare a standard solution?
Weight sample bottle containing liquid
Transfer solid to beaker and reweigh
Record difference in mass
Add distilled water and stir until dissolve
Transfer to volumetri flask
Make up to 250cm^3 mark with distilled water
What are the common errors when preparing a standard solution?
Systematic errors on balance
Lost substance in transfer and overfilling of volumetric flask
How do we reduce the chance of the common errors occurring when preparing a standard solution?
Washing methods
Reading volumes from the bottom of the meniscus
How do we reduce uncertainties in a titration?
Increase the titre volume needed for the reaction
What is the oxidation number of an element?
0
What is meant by oxidation and in terms of oxidation number?
Involves the loss of electrons
Results in oxidation number becoming more positive
What does the oxidation numbers in neutral compound add up to?
0
What is meant by reduction and in terms of oxidation number?
Involves the gain of electrons
Results in oxidation number becoming more negative
What is an oxidising agent?
Accepts electrons from the species that is being oxidised
Therefore it gains electrons and is reduced
Reduction in oxidation number
What is a reducing agent?
Donates electrons to the species being oxidised
Therefore it loses electrons and is oxidised
Increase in oxidation number
What is a disproportionation reaction?
A reaction where a species is both oxidised and reduced
What are the products between a metal and an acid?
Salt + hydrogen
