/6 Science Quiz (for 12 to 16 years old): Quiz 17 1 / 6Chlorophyll is a naturally occurring chelate compound in which central metal is calcium copper iron magnesium 2 / 6The gas usually filled in the electric bulb is carbon dioxide oxygen hydrogen nitrogen 3 / 6Quartz crystals normally used in quartz clocks etc. is chemically sodium silicate silicon dioxide germanium oxide a mixture of germanium oxide and silicon dioxide 4 / 6Carbon, diamond and graphite are together called isomers isomorphs allotropes isotopes 5 / 6Heavy water is rain water PH7 deuterium oxide tritium oxide 6 / 6Washing soda is the common name for Calcium bicarbonate Sodium bicarbonate Sodium carbonate Calcium carbonate Your score is 0% Restart quiz Next quiz Please rate the quiz Send feedback By WordPress Quiz plugin