Redox and acids Flashcards
Define oxidation
- Loss of electrons
- Increase in oxidation numbers
Define reduction
- Gain of electrons
- Decrease in oxidation numbers
Define redox reactions
Reactions in which both reduction and oxidation takes place simultaneously
Define an oxidising agent
Is a reagent which oxides another species
Define a reducing agent
Is a reagent which reduces another species
What is the oxidation number rule for any element on its own
Is 0
e.g Na = 0
What is the oxidation number rule for a simple ion
Is the charge on the ion
e.g Na+ = +1
o2- = -2
What is the oxidation number rule for a group 1,2 and 3 element in a compound
The charge is equal to group number
e.g KCl = +1 (K)
What is the oxidation number rule for a compound
The sum of the oxidation numbers of all atoms and ions in a compound
e.g Na2O = (2x1) + -2 = 0
What is the oxidation number rule for group 7 elements in a compound
Usually -1 ( but there are exceptions)
e.g Cl= -1
What is the oxidation number rule for hydrogen bonded to a non-metal
Is +1
e.g HCl = +1 (H)
What is the oxidation number rule for hydrogen bonded to a metal
Is -1
e.g LiAlH4 = -1(H)
What is the oxidation number rule for an oxygen in a compound
Usually -2
e.g Na2O = -2(O)
What is the oxidation number rule for an oxygen in a peroxide
Is -1
e.g H2O2 = -1 (O)
What is the oxidation number rule for a complex ion
The sum of the oxidation number of all atoms and ions in an ion is equal to the charge
e.g CO3 -2
+4 + (3x2) = -2
Define acid
Proton donors in solution
Define strong acid
Fully dissociates its H+ ions in aqueous solution
Define weak acid
Partially dissociates its H+ ions in aqueous solution
Define base
A proton acceptor
Define alkali
Is a type of base that dissolves in water forming OH- ions
Define salt
A compound produced when a H+ ion from an acid is replaced by a metal or another positive ion such as ammonium ion
What are the products and observations when an acid reacts with a base
Products= salt + water
Observations= Solid dissolves
What are the products and observations when an acid reacts with an alkali
Products= salt + water
Observations= no visible changes ( unless indicator is used)
What are the products and observations when an acid reacts with a carbonate
Products= salt + water + CO2
Observations= Solid dissolves and bubbles of gas
What are the products and observations when an acid reacts with a metal
Products= salt + H2
Observations= Solid dissolves and bubbles of gas
What salt is made when using hydrochloric acid
Makes a chloride salt
e.g MgCl2
What salt is made when using sulphuric acid
Makes a sulfate salt
e.g FeSO4
What salt is made when using ethanoic acid ( weak acid)
Ethanoate salt
e.g CH3COOK
What salt is made when using nitric acid
Makes a nitrate salt
