Chapter 4 - Acids and redox Flashcards
(29 cards)
Name some common acids and their formula
Hydrochloride acid, HCl (aq)
Sulfuric acid, H2SO4 (aq)
Nitric acid, HNO3 (aq)
What acids do to water?
They all dissociate to release hydrogen ions, H+ (aq) when dissolved in water.
What donors are acids
As a H+ ion is simply a proton acids can be defined as proton donors. The H+ ion is responsible for the reactions of acids
Why is hydrochloric acid a strong acid?
When it dissolves all the HCl molecules dissociate to release hydrogen ions.
Why is hydrofluoric acid a weak acid?
When it dissolves only a small proportion of the Hf molecules dissociate to release hydrogen ions.
Name some common bases and their formula?
Potassium hydroxide, KOH
Sodium hydroxide, NaOH
Ammonia, NH3
Other examples include metal oxides and metal carbonates
What are alkalis
Bases that dissolve in water are also known as alkalis.
They dissociate to release hydroxide ions, OH- (aq) when dissolved in water
How do bases neutralise acids?
Bases neutralise acids by accepting the protons donated by the acid. For example, the hydroxide from sodium hydroxide will accept a H- ion to form water
What is the neutralisation reaction for water?
H+ (aq) + OH- (aq) —> H2O (l)
What are bases defined as?
Proton acceptors
Why is sodium hydroxide a strong base
Sodium hydroxide is a strong base, as when it dissolves all of its hydroxide ions are available to accept protons
Why is ammonia a weak base?
Ammonia is a weak base as only a small proportion of the NH3 molecules will accept protons
What products occur when an acid reacts with a metal oxide give an example. (Magnesium oxide with nitric acid)
A salt and water is formed
Magnesium oxide + nitric acid —> magnesium nitrate + water
What products occur when an acid reacts with an alkaline e.g. potassium hydroxide and sulphuric acid
A salt and water
Potassium hydroxide + sulfuric acid —> potassium sulfate + water
What products occur when an acid reacts with a carbonate e.g calcium carbonate and hydrochloride acid
A salt, water and carbon dioxide is formed.
Calcium carbonate + hydrochloride acid —> calcium chloride + water + carbon dioxide
Define the term strong acid
A strong acid is a substance that fully dissociates to donate hydrogen ions dissolved in water
Name three common indicators used in acid base titrations and their colours in acids and bases
Methyl orange is red in acid, yellow in a base and turns orange at the end point.
Bromothymol blue is yellow in acid and blue in a base, it turns green at its end point.
Phenolphthalein is colourless in acid and pink in a base, it’s pale pink at its end point.
What is the formula for calculating concentration
Concentration = amount (mol) / volume (dm3)
What is the oxidation number of uncombined elements
0
What is the sum of all oxidation numbers in a compound
0
What is the oxidation number of an ion
The sum of all oxidation numbers in an ion equals the charge on the ion
What are the oxidation numbers on elements in groups 1, 2 and 3 in compounds
+1 +2 and +3
What is the oxidation number of Fluorine in all its compounds
-1
What is the oxidation number of hydrogen in its compounds (except metal hydrides)
+1
