The chemical reaction for CFC is: CCl3F = CCl2F + Cl. Uses. Due to their chemical properties, CFCs became useful as coolants and propellants. More commonly known as freon for refrigeration, CFCs are used extensively in appliances as a safe method of refrigeration. The other main use for CFCs has been as a propellant for aerosol cans.
The earliest known Egyptian pyramids are found at Saqqara, northwest of Memphis. The earliest among these is the Pyramid of Djoser (constructed 2630 BCâ2611 BC) which was built during the third dynasty. This pyramid and its surrounding complex were designed by the architect Imhotep, and are generally considered to be the world's oldest monumental structures constructed of dressed masonry.
Thought to be a gigantic tomb built for the the pharaoh Khufu over a 10 to 20-year period that ended somewhere around 2560 BC, the Great Pyramid of Giza in Egypt is the single remaining vestige of the Seven Wonders of the Ancient World.hen it was first built it was 146.5 metres high, before crumbling to 138.8 metres tall, where it stands now. There are three known chambers in the Great Pyramid-the base chamber sits on the bedrock and supports the rest of the pyramid, while the upper two chambers are called the Queenâs and Kingâs Chambers.