ES2: Redox Flashcards
Define “oxidation”
The loss of electrons or the gain of oxygen
Is hydrogen removed or gained in oxidation?
Removed
Give the general equation for oxidation.
K===> K+ + e-
Is there an increase or a decrease in oxidation numbers during oxidation?
Increase
Define “reduction”
The gain of electrons or the loss of oxygen
Is hydrogen removed or gained in reduction?
Gained
Give the general equation for reduction.
K+ + e- ===> K
Is there an increase or a decrease in oxidation numbers during oxidation?
Decrease
What is a redox reaction?
- A reaction where electrons are being transferred
- Reduction and oxidation take place simultaneously
What is a reducing agent?
A substance which donates electrons and becomes oxidised as it reduces another species
What is an oxidising agent?
A substance which accepts electrons and becomes reduced as it oxidises another species
Why do elements in diatomic molecules have an oxidation state of 0?
They haven’t accepted/donated any electrons
What oxidation state do elements in diatomic molecules have?
0
What oxidation state does fluorine have?
-1
What oxidation state does chlorine have?
-1 (except with O or F)
What oxidation state does oxygen have?
-2 (except with F or a peroxide)
What oxidation state does bromine have?
-1 (except with O, F or Cl)
What oxidation state does iodine have?
-1 (except with O,F,Cl or Br)
What oxidation state does hydrogen have?
+1 (except with metals)
What oxidation state do Group 1 metals have?
+1
What oxidation state do Group 2 metals have?
+2
What oxidation state does aluminium have?
+3
What oxidation state do compounds have overall?
0
What oxidation state do ions have?
The same as its charge
How do you work out the oxidation state in a complex ion/compound?
- Multiply the oxidation number by the number of atoms present
- Minus this value from the overall charge
What elements have systematic names?
- Transition metals e.g lead
- Halogens
How do you work out a compound’s systematic name?
- Find which element has the variable oxidation state
- Work out its oxidation number
What is an oxyanion?
A negative ion with oxygen in it
What is a chlorate?
A compound made up of chlorine and oxygen ions
What is the formula for a nitrate?
NO3-
What is the oxidation state of a nitrate?
-1
What is the formula for a sulfate?
SO4^2-
What is the oxidation state of a sulfate?
-2
What is the formula for a carbonate?
CO3^-2
What is the oxidation state of a carbonate?
-2
What is the formula of a hydroxide?
OH-
What is the oxidation state of a hydroxide?
-1
What is the formula of an ammonium ion?
NH4+
What is the oxidation state of an ammonium ion?
+1
What is the formula of a hydrogencarbonate?
HCO3-
What is the oxidation state of a hydrogencarbonate?
-1
What is the formula of a sulfide?
S^2-
What is the oxidation state of a sulfide?
-2
