C3.3 Types Of Chemical Reactions Flashcards
Reduction
Loss of oxygen from a substance
Oxidisation
Is
Loss of electrons
Reduction
Is
Gain of electrons
Oxidisation
Gain of oxygen by a substance
Also:
Oxidisation
Is
Loss of electrons
Reduction
Is
Gain of electrons
Oxidising agent
Substance that initially has the oxygen before the reaction
These accept electrons
Reducing agent
Substance that initially does not have the oxygen before the reaction
These donate electrons
Does a redox equation always involve oxygen
No
Acids
Substances that release H+ ions when it dissolves in water to make an aqueous solution.
Bases
Substances, usually metal hydroxides or metal oxides, that neutralise acids
If it dissolves in water, it is also called an alkali
Alkalis release OH- ions when they dissolve in water
pH < 7
Acidic
pH = 7
Neutral
pH > 7
Alkaline
Range of pH scale
0 to 14
Most acidic 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Most alkaline
I
Neutral
What is neutralisation
Reaction between an acid and a base, or an alkali
Forms a salt and water
Neutralisation equation
Acid + base -> salt + water
How do you predict salt made from neutralisation
First part comes from the metal in the base or alkali
Exception: If ammonia or ammonium carbonate is used, name starts with ammonium
Second part of the name comes from the acid used such as
- Chloride (hydrochloride acid)
- Nitrate (nitric acid)
- Sulphate (sulphuric acid)
What salt is formed with hydrochloride acid? (HCl)
Chloride
What salt is formed with nitric acid? (HNO3)
Nitrate
What salt is formed with sulfuric acid? (H2SO4)
Sulfate
What salt is formed with phosphoric acid? (H3PO4)
Phosphate
Predicting a neutralisation reaction
1) identify salt produced
2) write the word equation
3) Write balanced chemical formula underneath with state symbols
What happens during neutralisation in solution
H+ ions from acidic solutions and OH- ions from alkaline solutions react to produce water.
H+(aq) + OH-(aq) -> H2O(l)
Salt produced depends on other ions present in the alkali and acid.
What are carbonates
Ionic compounds that contain the carbonate ion CO3²⁻
Reaction between acid and carbonate
Acid + carbonate -> salt + water + carbon dioxide
What carbonates are soluble in water
Sodium carbonate
Ammonium carbonate
Group 1 metal carbonates
Reaction between acids and metals
Acid + metal -> salt + hydrogen
Dilute acid
Contains a low ratio of acid : volume of solution
Concentrated acid
Contains a high ratio of acid : volume of solution
Weak acid
partially ionised in solution of water
Small fraction of their molecules release H+ ions
Strong acid
completely ionised in solution of water
All of their molecules release H+ ions
⇌ symbol
Shows the reaction does not go to completion
Reversible reaction
What happens when the pH of a solution decreases by 1
Concentration of H+ ions increase by a factor of 10
Multiply by 10
Concentration of H+ ions decreases by a factor of 10 is pH increases by 1
Digide by 10
pH titration curve
Shows effect on pH of changing the hydrogen ion concentration during a neutralisation reaction
Acid, salt and negative ion of chlorine
Acid: Hydrochloric
Salt: Chloride
Negative ion: Cl ⁻
2CI –> Cl2 + 2e- (anode)
Acid, salt and negative ion of nitrogen
Acid: Nitric
Salt: Nitrate
Negative ion: NO₃
Acid, salt and negative ion of sulfur
Acid: Sulfuric
Salt: sulfate
Negative ion: SO²⁻
Acid, salt and negative ion of phosphorus
Acid: Phosphoric
Salt: Phosphate
Negative ion: PO₄³⁻
What is formed when a group 1 metal reacts with water
Metal + water -> metal hydroxide + hydrogen
More reactive metals displace…
Less reactive metals from their compounds.
Reaction between acid and metal oxide
Acid + metal oxide -› salt + water
Example: H2SO4(aq) + CuO(s) -› CuSO4(aq) + H2O(l)
