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.
Egyptian pyramid of Khufu. The largest Pyramid, King Khufu s, is often called the Great Pyramid. It lies in the desert west of Giza, accompanied by the pyramids of Khafre and Menkaure (Khufu s son and grandson). The Great Pyramid was built during Khufu s reign (2551 bc-2528 BC).ncient Egyptian Pyramids in Giza. Egyptian pyramids are great monument of a great civilization that was born seven thousand years ago. The ancient Egyptians built more than 90 royal pyramids, from about 2630 BC until about 1530 BC.