chemistry-C3 quantative chemistry

conservation of mass

the total mass of the products in a reaction will always be equal to the total mass of the reactants, this is because no atoms are ever destroyed or created during a reaction

how do you find the concentration of a solution in g/dm3

divide the mass of solute in grams by the volume of the solution in dm3

how do you calculate the percentage mass of an element in a compound?

multiply the Ar of the element by the number of atoms of that element in the formula of the compound. then divide the compounds Mr and multiply by 100

is the Mr of a compund always greater than the Ar of any of the elements in that compound?

yes as you find the Mr by adding up the Ar of each element so it must be greater

the Mr of methane, CH4 is 16, the Ar of carbon is 12 what is the percentage mass of carbon in methane?

what is the mass of sodium sulfate is there in 100cm3 of sodium sulfate solution if the solution has a concentration of 5g/dm3?

100cm3=100/1000=0.1dm3
concentration = mass / volume
5 x 0.1 = 0.5g