Acid/Base and Reactions

​definition of acids and bases

​pH scale

​indicators

​neutralisation reactions

• ​acid+ base

• ​acid + carbonate

pH less than 7

​turns blue litmus paper red

​often sour

​produces H+ ions in solution

​pH greater than 7

​turns red litmus paper blue

​often bitter

​produces OH+ ions in solution

​used to measure the acidity or basicity of a substance

​takes the negative logarithmic value of H+ ions OR substances with more H+ ions will ne lower on the pH scale

​Therefore, acids are low on the pH scale, and bases are high

​we use pH indicators to test the pH of substances

​their colour will change depending on the pH

​gives a visual indicator, numerical pH values are given by technology

​universal indicator is the most common

​acid + base --> salt + water

​neutralisation reaction

​not always the case, but for now this is a good general equation

​since you know the products, all you have to do is balance

​acid + carbonate --> salt + water + carbon dioxide

​again, a neutralisation

​often used to see whether a substance is acidic

​heating carbonates always decomposes the carbonate into its metal oxide + carbon dioxide

• ​metal carbonate + heat --> metal oxide + CO₂