Quantitative Chemistry Flashcards
Use your Periodic Table to find the relative atomic mass, Ar (or RAM), of carbon.
12 (not 6!)
Use your Periodic Table to find the relative atomic mass, Ar (or RAM), of bromine.
80
Use your periodic table to calculate the relative molecular mass, Mr (or RAM) for water, H2O
H + H + O = 1 + 1 + 16 = 18
Use your periodic table to calculate the relative molecular mass, Mr (or RAM) for calcium carbonate, CaCO3
Ca + C + O + O + O = 40 + 12 + 16 + 16 + 16 = 100
Calculate the percentage by mass of oxygen in water
Mass of O/Mr x 100 = 16/18 x 100 = 89%
Calculate the percentage by mass of hydrogen in water
Mass of H/Mr x 100 = 1+ 1/18 x 100 = 11%
What name is given to the quantity obtained by weighing out the Ar of any element or the Mr of any compound in grams?
1 mole
Why is the quantity of 1 mole important?
1 mole of any substance contains the same number of particles. This number is huge: 6.02 x 10exp23
What is the mass of 1 mole of argon atoms?
40g
What is the mass of 2 moles of nitrogen molecules, N2?
1 mole = 14 + 14 = 28g, so 2 moles = 28 x 2 = 56g
How much hydrogen chloride can be obtained from 100g of hydrogen?
H2 + Cl2 –> 2HCl
3650g
Calculate the mass of magnesium sulphate that would be obtained from 4g of magnesium.
Mg + H2SO4 –> MgSO4 + H2
20g
What is the yield?
The mass of product obtained in the reaction
What is the theoretical yield?
The theoretical yield is the maximum amount that can possibly be obtained in a reaction.
What is the actual yield?
The actual yield is the amount that is actually obtained.
