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.
The first Egyptian pyramid is believed to be the Pyramid of Djoser, it was built in Saqqara around 4650 years ago (2640 BC). Saqqara is a huge ancient burial ground built near the Egyptian city of Memphis. The Great Pyramid of Giza is the oldest and largest of three pyramids in the Giza Necropolis.njoy our range of interesting Ancient Egyptian pyramid facts for kids. Learn about the first pyramid built in Egypt, the Great Pyramid of Giza, important burial sites such as Saqqara, what Egyptians put in burial tombs, where the famous mask of Tutankhamun was discovered and much more.