C3.3 Flashcards
What is oxidation
Oxidation is loss of electrons.
What is reduction
Reduction is the gain of electrons.
Different oxidation definition
Oxidation is when a substance gains oxygen
Different reduction definition
Reduction is when a substance loses oxygen
What is the oxidising agent
The substance that gets reduced is the oxidising agent.
What is the reducing agent
The substance that gets oxidised is the reducing agent.
What is an acid
An acid is a substance that releases H+ ions when dissolved in water to make an aqueous solution.
HCl -> H+ + Cl-
What is a base
A base is a substance that can neutralise acids. If a base can dissolve inn water it is an alkali. Alkali’s release OH- ions in the water.
NaOH -> Na+ + OH-
What does the PH scale describe
The PH scale describes the relative acidity or alkalinity.
PH < 7 = acidic
PH = 7 = neutral
PH > 7 = alkaline
What is the PH of a strong acid and alkali
Strong acid PH-0, strong acid PH-14
What is neutralisation
Neutralisation is the reaction between an acid and a base, or an alkali to form salt and water only. The salt depends upon the acid or base used.
General equation of neutralisation
acid + base –> salt + water
Characteristics of a neutralisation reaction
In a neutralisation reaction the PH becomes 7, but may become more acidic or alkali depending on how much of each product is added.
How to name the salt produced
First part comes from the metal in the base or alkali exception is when ammonia or ammonium carbonate is used resulting in ammonium.
Second part of the name comes from the acid.
Acid used for type of salt made
HCl - chloride
Nitric acid - nitrate
Sulphuric acid - sulphate
Phosphoric acid - Phosphate
Ionic equation for neutralisation
The H+ and OH- ions react to create water. H+ + OH- -> H2O
What does the salt produce depends on
The salt produced depends on the other ions present e.g. Na+ and OH-
What happens when a metal reacts with water
A metal hydroxide and hydrogen form
What are carbonates
Carbonates are ionic compounds that contain CO3 2-. Carbonates react with acids to form a salt, plus water + CO2.
General formula for carbonates + acid
acid + carbonate -> salt + water + carbon dioxide
General formula for metal + acid
acids + metal -> salt + hydrogen
What is a dilute acid
A dilute acid contains a low ratio of acid to volume of solution.
What is a concentrated acid
A concentrated acid contains a high ratio of acid to volume of solution.
What is a weak acids
A weak acid is partially ionised (only a small fraction of their molecules release H+ ions)
What is a strong acid
A fully ionised (all their molecules release H+ ions).
What happens when the concentration of H+ ions increases by a factor of 10
The solution of the solution increases by 1
What does a strong acid have lower than a weak acid at the same concentration
higher PH
when does an acid have a lower PH
When it is concentrated
What does a PH titration curve show
It shows the effect of the PH of changing the H+ ion concentration during a neutralisation reaction.
