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.
Currently it is celebrated in more than 192 countries each year. It was originally celebrated at Spring Equinox around 21 March every day but now the United Nations has designated 22 April as the International Mother Earth Day. Earth Day Network coordinates this annual day across the globe.