posted by Kenah Smith on .
To extract gold from its ore, the ore is treated with sodium cyanide solution in the presence of oxygen and water.
4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O(l) 4 NaAu(CN)2(aq) + 4 NaOH(aq)
(a) Determine the mass of gold that can be extracted if 29.3 g sodium cyanide is used.
(b) If the mass of the ore from which the gold was extracted is 146.5 g, what percentage of the ore is gold?
You don't have an arrow. How do you know where the reactants stop and the products begin?
4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O(l) --> 4 NaAu(CN)2(aq) + 4 NaOH(aq)
oh sorry, here it is!
mols NaCN = grams/molar mass
Using the coefficients in the balanced equation, convert mols NaCN to mols Au.
Now convert mols Au to g Au. g = mols Au x atomic mass Au. This is the theoretical yield of Au.
%yield = (actual yield/theor yield)*100 = >