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 United Nations has declared September 21 as the International Day of Peace. In a message commemorating the Day in 1995, Secretary-General Boutros-Ghali stated that the world, once more, cries out for peace. And for the economic and social development that peace alone can assure...