Abright light is produced when magnesium reacts with oxygen

How many oxygen atoms are there in 3.15 moles of hcl manganese (iv) oxide, mno2

Asuspension of yeast cells is being grown under anaerobic conditions such that glucose is degraded to ethanol and carbon dioxide. if one wishes to follow this process by monitoring the release of 14co2, at which positions in the glucose molecule would the 14c label need to be incorporated?

Give one example of a pure (exact) number and of an estimated (measured) number.