DEMONSTRATION: Cu turnings and conc / dilute nitric acid.
WARNING: THIS MUST BE DONE IN A FUME CUPBOARD .
With dilute nitric acid
Add 50 mls of 2.0M nitric acid to 2g of copper turnings in a large conical flask.
Record what happens.
With concentrated nitric acid
Add 50 mls of concentrated nitric acid to 2g of copper turnings in a large conical flask.
Record what happens.
EXPLANATION
With dilute nitric acid there is no observable reaction.
When concentrated nitric acid is added to copper turnings there is an obvious chemical
reaction.
Brown fumes of nitrogen dioxide are liberated (DANGER)
The copper turnings react with green copper nitrate solution being formed.
A lot of heat is generated.
The best experimental set up for this experiment is shown in the diagram below.
WHAT HAPPENS
Brown fumes of NO2 are produced. These are absorbed in the water
Copper reacts forming green copper nitrate.
On cooling water enters the conical flask and the copper nitrate solution turns light blue.
This is perhaps the safest way of doing this experiment.
WARNING: THIS MUST BE DONE IN A FUME CUPBOARD .
FOR THE TECHNICIAN
measuring cylinder
2g of copper turnings
50 mls of dilute nitric acid
50 mls of concentrated nitric acid
2 large conical flasks
delivery tube
tall beaker
bunsen mat
HAZARD WARNINGS
Concentrated nitric acid
Corrosive
Causes severe burns
An oxidising agent
Avoid contact with combustible material
Nitrogen Dioxide
A brown irritating gas – very toxic when breathed in.
Symptons – headaches and dizzyness.
Asthma sufferers are susceptible.
ONLY PREPARE IN A FUME CUPBOARD