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