Chemistry Chemical Changes March 2018 Flashcards
What is the most reactive metal?
Potassium
What is the least reactive metal?
Platinum
What metals do not react with oxygen?
Silver, Gold and Platinum
What metals react with water?
Potassium, Sodium, Lithium, Calcium and Magnesium
What metals react violently with acids?
Potassium, Sodium and Lithium
What metals react normally with acids?
Calcium, Magnesium and Aluminium
What metals react slowly with acids?
Zinc, Iron, Tin and Lead
What metals don’t react with acids?
Copper, Silver, Gold and Platinum
Metal + Oxygen = ?
Metal Oxide
Metal + Water = ?
Metal Hydroxide + Hydrogen
Metal + Acid + ?
Metal Salt + Hydrogen
What is an example of a salt?
Potassium + Hydrochloric acid = Potassium Chloride + Hydrogen
What is the definition of oxidation?
Oxidation - A reaction where a substance loses
electrons.
Reduction - A reaction where a substance gains
electrons.
Mnemonic -
OIL RIG
O - Oxidation
I - Is
L - Loss of electrons
R - Reduction
I - Is
G - Gain of electrons
Where is carbon on the reactivity scale? Hydrogen?
Carbon - Between Aluminium and Zinc (7th from top)
Hydrogen - Between Lead and Copper (5th from
bottom)
What is a displacement reaction?
A reaction where a more reactive element takes the place of a less reactive element in a compound.
What is a redox reaction?
A reaction where both reduction and oxidation takes place.
e.g 2Al+Fe2O3 –> Al2O3+2Fe
What are acids and alkalis?
Acid - A solution with a pH less than 7; produces H+
ions in water.
Alkali - Solution with a pH more than 7; produces OH-
ions in water.
(pH of 7 is neutral)
What is the difference between strong and weak acids?
Strong - An acid in which all the molecules break into
ions in water.
Weak - An acid in which only a small fraction of
molecules break into ions in water.
What is a salt?
- A substance made when acids react with metals,
metal hydroxides, metal oxides and metal carbonates. - Found in many medicines, fertilisers, toothpaste and
food additives.
What is electrolysis?
The decomposition of ionic compounds using electricity.
What are the electrodes? What is an electrolyte?
Anode - An electrode where oxidation takes place. In
electrolysis it is the positive electrode.
Cathode - An electrode where reduction takes place. In
electrolysis it is the negative electrode.
Electrolyte - A liquid that conducts electricity.
What is discharge (of ions)?
The gain or loss of electrons to become electrically neutral.
What are ionic equations and half equations?
Ionic - An equation that shows all ionic charges in a
reaction not including ones that do not change.
(Cu + 2Ag+ –> Cu2+ + 2Ag)
Half - An equation that shows the gain or loss of
electrons to an ion. (Ag+ + e- –> Ag)
‘Original equation = Cu + 2AgNO3 –> Cu(NO3)2 + 2Ag’
