Answer to Question #149017 in General Chemistry for Franchesca A Casillas

Question

Gold can be extracted from the surrounding rock using a solution of sodium cyanide. The first step in this process is: 4Au (s) + 8NaCN (aq) + O2 (g) + 2H2O (l) \rightarrow→ 4 NaAu(CN)2 (aq) + 4NaOH (aq) If a sample of rock contains 0.009% gold by mass, how much NaCN is needed to extract the gold from 1 metric ton (1 metric ton = 103 kg) of rock as NaAu(CN)2?

Answer 1

8x(23+12+14) = 392.

392 x 0.009 x 103 x 1000 / 100 x 4 x 197 = 4,61147208 g of NaCN