acids and salts

• the H+ ion is the active ingredients in acids , an H+ ion is responsible for all acid reactions
• an acid is a proton donor
• strong acids give up H+ ions easily this means that in solution they fully dissociate
• weak acids do not give up H+ ions as easily, once H+ ions are released from weak acids they are quickly taken back again as they are good at accepting the H+ ions back because of this weak acids only partially dissociate
• a base is a proton acceptor and can neutralise acids
• an alkali is a special type of base that is able to dissolve in water to form aqueous hydroxide ions
• when ammonia dissolves in water it forms a weak alkaline solution of ammonium ions and hydroxide ions
• some substances can behave as acids and bases, they are called amphoteric substances
• salts are ionic compounds where the positive ion is a metal ion or an ammonium ion and the negative ion is derived from an acid
• acid + carbonate -> salt + carbon dioxide + water
• acid + metal oxide -> salt + water
• acid + alkali -> salt + water
• acid + metal -> salt + hydrogen
• when acids are neutralised by ammonia, ammonium salts are formed
• hydrated salts contain water of crystallisation in its structure
• anhydrous salts contain no water in their crystalline structure
• water of crystallisation is the water molecules that form an essential part of the crystalline structure of a compound
• methyl orange is red in acid and yellow in alkali
• bromothymol blue is yellow in acid and blue in bases
• phenolphthalein is colourless in acid and pink in bases