Chemical changes C4 Flashcards
Define an acid
Acids ionise in a water solution to form H+ ions. They have a pH of less than 7
Define a base and an alkali
higher pH than 7. Alkalis ionise in solution to form OH- ions
What is a neutralisation reaction?
A neutralisation reaction is when an acid and alkali react together with the product being neutral
Acid + base = salt + water
H+ + OH- = H₂O
What are titrations used for?
A method of analysing the concentrations of solutions
How do you determine when the end point of titration has been reached?
When the colour has changed.
Name three strong acids.
sulfuric acid, hydrochloric acid, nitric acid
what do acids and metal oxides react to create?
salt + water
What is the reactivity series?
The list that orders metals in order of reactivity towards other substances
what is oxidation and reduction?
Oxidation - Loss of electrons
Reduction - Gain of electrons
What is a redox reaction?
A reaction where both oxidation and reduction happen
What is an electrolyte?
a liquid or solution that can conduct electricity
How does electrolysis work?
An electric current passes through an electrolyte. the ions move towards the electrodes where they react and the compound decomposes
What reaction happens at the negative electrode?
A reduction reaction happens at the negative electrode
What reaction happens at the positive electrode?
An oxidation reaction happens at the positive electrode
What do half equations show?
they show the reactions at the electrodes
