Question

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?

Answer 1

You don't have an arrow. How do you know where the reactants stop and the products begin?

Answer 2

4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O(l) --> 4 NaAu(CN)2(aq) + 4 NaOH(aq)

oh sorry, here it is!

Answer 3

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.

b.
%yield = (actual yield/theor yield)*100 = >