Quantitative chemistry


The relative atomic mass of an element is the mass compared to which element?


Which is the correct relative molecular mass, Mr, for ethane C2H6? (Ar of C = 12, Ar of H = 1)


What is the percentage by mass of carbon in calcium carbonate CaCO3? (Ar of Ca = 40, Ar of C = 12, Ar of O = 16)


How many moles are present in 1 g of NaOH? (Ar of Na = 23, Ar of O = 16, Ar of H = 1)


In the following equation, what is the molar ratio between hydrochloric acid and copper(II) oxide? 2HCl + CuO → CuCl2 + H2O


In the reaction shown by the following equation, what mass of sulfur dioxide can be produced when 4 g of sulfur reacts with excess oxygen? (Ar of S = 32, Mr of O2 = 32, Mr of SO2 = 64). S + O2 → SO2


In an experiment, the actual yield is 8.4g but the theoretical yield is 17.0g. what is the percentage yield?