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