Oxygen in the air. The percentage of oxygen in the air can be measured by passing a known volume of air over hot copper, and measuring the decrease in volume as the oxygen reacts with it. Here are the equations for this reaction: copper + oxygen â copper oxide. 2Cu + O2 â 2CuO.
Get ready - World Backup is March 31st! About World Backup Day is a day for people to learn about the increasing role of data in our lives and the importance of regular backups.
The World Thinking Day is celebrated every year around the world on 22nd February by Girl Scouts and Girl Guides. The day is celebrated to appreciate the help and guidance of brothers and sisters around the world.