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