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.
What is Amazon Prime Day? Amazon Prime Day is an all-day online deals event that's essentially Black Friday in the summer. This year's Prime Day takes place on July 12, and, as the name suggests, you'll need an Amazon Prime membership ($99 per year, or $10.99 per month) to participate. If you don't have a Prime account, you can sign up for one or get a free trial here. Amazon Prime.