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