81. There is 1 carbon, 2 chlorine and fluorine atoms in Freon 12. To draw them it forms a cross with C in the middle and Cl and F both on the opposite side.
Cl
l
F - C- F
l
Cl
82. Freon-12 and Freon-14 are called halocarbons or just halides.
Hydrogen and oxygen cn form a polar covalent bond
Crush the limestone... it would give more area for the acid to react
Galileo disproved the Ptolemaic theory, sanctioned for centuries by the Church, which held the Earth to be the central and principal object in the universe, about which all celestial objects orbited.
