What is always included in a comparative investigation

For the reaction shown, calculate how many moles of no2 form when each of the following completely reacts. 2n2o5(g)→4no2(g)+o2(g) part a 1.0 mol n2o5 express your answer using two significant figures. nothing mol m o l request answer part b 5.4 mol n2o5 express your answer using two significant figures.

How many grams are in 68.2 molecules of br2?

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