for example. if you are given that a lead concentrate contains a percentage of PbS (you are given the percentage in the question but i don't want to know the answer!) how would you work out the percemtage of Pb in the conventrate?
whats the formula?
thanksHow do you calculate the percentage of an ore?
Molar Mass (Pb)
------------------------ x 100% = Answer
Molar Mass (PbS)How do you calculate the percentage of an ore?
Chemists use the concept of the "mole" to calculate mass. A mole is a number like "PI", but chemists never use the actual number. Instead, they rely on the fact this many atoms of any element has a characteristic weight. Lead is 207 grams per mole and Sulfur is 32 grams per mole. Therefore 1 mole of Lead sulfide is 207 + 32 = 239 grams per mole. The percentage of either Lead or Sulfur is just the atomic weight divided by the molecular weight. For Pb, it would be 207/239, or 86.6% Lead. The Sulfur is just the remainder, 100% - 86.6% is 13.2 % Sulfur. This works because there is just one other atom in the formula. When calculating the percentages of things like H2O, take twice the atomic weight of H because there are two of them in the molecule. If the ore contains just a fraction of PbS, multiply this fraction by the percent of either Pb or S. If the ore was 12% PbS, then the amount of Lead would be 12% times 86.6%, or 0.12 times 0.86 = 10 percent Lead.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment