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