…….and the students in the next video are successfully studying sixth form chemistry. If they can do it so can you……..its OK to be a chemistry geek!
Look at the three videos of the reactive metals sodium and calcium when small pieces are dropped into water. Observations allow us to work out what is happening and develop a general word equation for the reactions.
Some stuff for experts:
- sodium dissolves in water. A new compound must be formed in the solution.
- calcium dissolves in water. Another compound must be formed in solution
- What could this compound be? Acidic solutions contain lots of hydrogen ions. Basic solutions contain lots of hydroxide ions.
- Phenolphthalein indicator turns from colourless to pink when it is in a basic solution. When phenolphtalein turns pink there are hydroxide ions present.
- As the metals dissolve in water hydroxide ions are produced
- When sodium dissolves in water sodium hydroxide is formed in solution.
- When calcium dissolves in water calcium hydroxide is formed.
- A gas is given off which pops when lit
- When sodium and calcium dissolve in water hydrogen gas is formed
If you have followed all of that well done, if not don’t worry. For achievement in level 1 chemistry you simply have to remember the word equations and use them.
reactive metal + water —–> metal hydroxide + hydrogen
Sodium + water —–> sodium hydroxide + hydrogen
Calcium + water —–> calcium hydroxide + hydrogen
For merit and excellence you need to be able to write underneath the word equation the chemical formulae and then balance. See the exercises in your workbook.
Leave any questions you want answered by clicking on the response link. Good luck
and finally definitely DO NOT TRY THIS AT HOME
I think chemical reactions such as combustion in the fire, fermentation and the reduction of ores to metals were known since antiquity