Required Practical 08: Making Salts
About this practical...
In this practical, you get a chance to really put theory into practice. You will learn about the combinations of acids and either metal carbonates or metal oxides that can be used to make a specific soluble salt. Focus on the key steps of the process and ideas like why we potassium salts are made from potassium hydroxide rather than potassium metal.
Method:
1. Add 25cm3 of sulfuric acid into a 100cm3 beaker
2. Stir in 5g of copper oxide powder ensuring that it is still visible after stirring (in excess)
3. Set up a filter paper and funnel inside a conical flask
4. Pour the mixture through the funnel and collect the filtrate
5. Pour the filtrate into an evaporating basin and heat gently. When the solution boils, remove the flame then return it when the boiling stops.
6. Heat until crystals first appear around the edges then turn off the heat. It is critical that you leave plenty of solution in the basin and do not try to boil it dry.
7. Leave the crystals to grow (cool and crystalise). You may remove some, when cool enough, using a spatula and pat them between two paper towels then place into an evaporating dish for next lesson.
Safety & Managing Risks
Usual lab rules must be followed: loose hair tied back, goggles worn throughout the lesson, bags and stools tucked away and notify the teacher of any spills or breakages immediately. Take care when using the Bunsen. It is crucial that you do not boil the solution dry in the evaporation dish as it will spit and hot crystals will potentially land on people. For more detailed information, please consult CLEAPSS.
Technician notes:
1.0 mol/dm3 Sulfuric acid
Copper (II) Oxide powder
Spatulas
Glass rods
25 cm3 measuring cylinders
Balances around the lab
100 cm3 beakers and 250cm3 beakers
Filter funnels
Filter paper
Small conical flasks
Evaporating basins
This page was updated on: 8th January 2022