"Tumbaga was the name given by Spaniards to a non-specific alloy of gold and copper, which they found in widespread use in pre-Columbian Mesoamerica and South America. The proportion of gold to copper in artifacts varies widely; items have been found with as much as 97% gold while others instead contain 97% copper (text from Wikipedia). A 5.65 g sample of Tumbaga was submitted for analysis. You put the sample into concentrated nitric acid, where the copper (but not the gold) reacts with nitric acid via an oxidation-reduction reaction to produce NO2, a poisonous brown gas and H2O. The NO2 is collected at 25 ° C over water (remember what gas ""collected over water"" means). The collected gas occupies 676.5 mL at a total pressure of 793 mm Hg. Calculate the percent copper (by mass) in the sample. (Assume that all of the copper in the sample dissolves.) Submit your answer as a video in which you show your work for solving the problem and describe your process for solving the problem (similar to previous recitation videos) 1 Cu(s)+ 4 HNO 3(aq) → 2 NO 2(g) + Cu(NO 3) 2(aq) + 2 H 2O(l)"