Reacting masses1 calcium carbonate breaks down on heating to produce calcium oxide and carbondioxide gas. caco3 + cao + co2a student heats 15 g of calcium carbonate strongly in a crucible. relative atomic masses (a): ca = 40, c = 12, o = 16.calculate the mass of calcium oxide produced by this reaction.(5 marks)

Which best explains why an iceberg floats?

Agroup of students is studying convection current. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other is in an area with warm air. after 10 minutes, the balloon are released from a height of 1 meter. which of the following to the students most likely observe? a) the warm balloon expands and rises. the cold balloon shrinks and sinks b) the balloon both rise. the cold balloon is larger than the warm balloon c) the cold balloon expands and rises. the warm balloon shrinks and sinks d) the balloon rise at the same rate. both balloons are the same size

Which of the following describes a compound? (hint: carbon and oxygen bo a. a piece of pure carbon, containing only carbon atoms b. oxygen gas surrounding a solid piece of carbon c. a substance made of two oxygen atoms for each carbon atom carbon and oxygen atoms mixed without being bonded together