Acids and Alkalis Flashcards
what is the pH scale?
The pH scale is the measure of how acidic or alkaline a substance is from 0 - 14, 1-6 is acidic and 8-14 alkaline with pH 7 being neutral
what is an acid?
An acid is a substance with a pH of less than 7 and form H+ ions
what is a base?
A base is a substance that has a pH greater than 7
what is an alkali?
An alkali is a base that dissolves in water and form OH- ions
what is the neutralisation equation?
Neutralisation is when an Alkali + Base —–> Salt + Water
what is the equation for when metals and acids react?
Acid + Metal ——-> Salt + Hydrogen
what is the equation for when acids and metal oxides react?
Acid + Metal oxide ——–> Salt + Water
what is the equation for when acids and metal hydroxide react?
Acid + Metal hydroxide ——–> Salt + water
how do you make a soluble salt using a metal or insoluble base?
To make soluble salts you first need to pick the correct acid and metal or insoluble base (oxide and hydroxide) to make the product you want. You then need to add them both together so that the solid will slowly dissolve in the acid as it reacts, when it is done the excess solid will just sink to the bottom. Finally you filter the material to get the salt solution and evaporate and leave to form crystals
how do you make soluble salts using an alkali?
To make soluble salts you need to use universal indicator to show the neutralisation process, you have to have the exact amount. Firstly you need to add the universal indicator to a specific amount of acid, then record the amount of alkali it takes to neutralise the substance. Repeat this without the indicator using the same amount of acid an alkali as before. Then just evaporate and leave to crystallise
how do you make insoluble salts (precipitation)?
To make insoluble salts you need to firstly pick two solutions that contain the ion that you want. You then need to mix the two solutions together, once the salt has precipitated out you need to filter it and wash and dry it on filter paper
