I'm confused plz help! Chem!!?
Gold metal can be dissolved using sodium cyanide according to the reaction below:
4 Au(s) + 8 NaCN (aq) + O2(g) + 2 H2O(l) → 4 NaAu(CN)2(aq) + 4 NaOH(aq)
If I added 86.7 g of Au to 750 mL of a 1.8 M solution of NaCN, which reagent would be limiting?
Type the reagent which is limiting (Au or NaCN or neither if there is no limiting reagent)
Based on the limiting reagent, how many L of oxygen are required at 33 oC and 705 mmHg?
Give this answer to 3 significant figures.
- Roger the MoleLv 71 month ago
4 Au + 8 NaCN + O2 + 2 H2O → 4 NaAu(CN)2 + 4 NaOH
(86.7 g Au) / (196.966569 g Au/mol) = 0.440176 mol Au
(0.750 L) x (1.8 mol NaCN/L) = 1.35 mol NaCN
0.440176 mole of Au would react completely with 0.440176 x (8/4) = 0.880352 mole of NaCN, but there is more NaCN present than that, so NaCN is in excess and
Au is the limiting reagent.
(0.440176 mol Au) x (1 mol O2 / 4 mol Au) = 0.110044 mol O2
V = nRT / P = (0.110044 mol) x (62.36367 L mmHg/K mol) x (33 + 273) K /
( 705 mmHg) = 2.98 L O2