Gap-fill worksheet question Quiz "METHODS of MAKING SALTS"

Select answers and CHECK. Copying NOT permitted © Doc Brown's Chemistry Clinic

   7      acidic      alkaline      ammonium      bases      blue      burette      chloride      colour      crystallises      dissolve      dissolves      evaporate      evaporated      filtered      filtrate      green      indicator      neutral      neutralised      nitrate      oxides      pH      red      repeated      salt      sulphate      water   
(1) When a substance dissolves in water it forms an aqueous solution which may be acidic, or neutral. Water itself is . An can be used to show how acidic or alkaline a solution is by the way the changes. The scale is used to show numerically how acidic or alkaline a solution is. If the pH = the solution is neutral, if the pH is over 7 it is and if it is less than 7 it is .

(2) SolBasePrepQ.gifQ2 Compounds of alkali metals called salts can be made by reacting solutions of their hydroxides which are alkaline with acids. In these neutralisation reactions:
acid + alkaline hydroxide solution ==> a neutral solution +

step A A known volume of acid is measured out with a measuring cylinder or more accurately with a pipette and suction bulb and universal indicator is added and turns .

step B The alkali is added with a measuring cylinder, or more accurately with a .

step C The alkali is added until the indicator turns . The volume required for neutralisation is noted. If too much alkali is added the indicator turns !

step D The procedure can now be without the contaminating indicator. The solution is then to reduce the amount of water.

step E The hot concentrated solution can be left to cool until the salt from solution.

(3) The particular salt produced in any reaction between an acid and an alkali depends on the acid used and the metal in the alkali. Neutralising hydrochloric acid produces a , nitric acid produces a and neutralising sulphuric acid makes a . Ammonia also dissolves in water to produce an solution. This can be neutralised with acids to produce salts. In the salt preparation an indicator can be used to show when acidic and alkaline solutions have been completely to produce a neutral solution.

(4) InsolBasePrepQ.gifQ4 Salts of transition metals, as with some other metals, can be made by reacting their , hydroxides or carbonates with acids. Transition metal oxides and hydroxides do not in water and are called insoluble .

step A To produce a solution of a soluble transition metal salt, the metal oxide (or hydroxide or carbonate) is added to an acid until no more will react.

step B The excess metal oxide (or hydroxide) can then be off. The fact that no more tells you all the acid has been .

step C The clear solution is then warmed to water until the salt from soltion.