Chapter 4 - Acids and Redox Flashcards
Acids, bases and neutralisation, Acid-base titration and Redox.
What is an acid?
When dissolved in water, it will release hydrogen ions as protons into the solution.
What is a strong acid?
Releases all of its hydrogen atoms into solution.
It completely dissociates in aqueous solution.
What is a weak acid?
Releases a small proportion of its available hydrogen atoms into solution.
It partially dissociates in aqueous solution.
What is a base?
A base neutralises an acid to form a salt.
What is an alkali?
A base that dissolves in water releasing hydroxide ions into the solution.
What is the word equation for the neutralisation of acids with metal oxides/hydroxides?
Metal oxide/hydroxide + acid -> salt + water
What is the word equation for the neutralisation of acids with alkalis?
Acid + alkali -> salt + water
What is the word equation for the neutralisation of acids with carbonates?
Carbonate + acid -> salt + water + carbon dioxide
What is a titration?
A technique used to accurately measure the volume of one solution that reacts exactly with another solution.
What are the uses of titrations?
Finding the concentration of a solution.
Identification of unknown chemicals.
Finding the purity of a substance.
What are concordant results?
Within 0.10 cm^3 of each other.
When can a mean titre be worked out?
When two or more concordant results are obtained.
When is the oxidation number zero?
For elements on their own or bonded to atoms of the same element.
What is the common oxidation number of oxygen?
-2
What is the common oxidation number of hydrogen when bonded to non-metals and metal
+1 non metal
-1 with metal
What is the common oxidation number of fluorine?
always -1
What is the common oxidation number of Na+ or K+?
+1 as they group 1