Question

limiting reagent ml

Cu 2. In reaction (G), suppose that you add 3.5 ml of 6 M nitric acid to a sphere of copper metal that weighs 0.41 grams. Which reactant is the limiting reagent? (Show your work) Cu 3.55, mう55 CHEM1414-AY-2017-2018

Answer 1

Balanced equation for reaction between Cute and HNO3

3 Cu(s) + 8 HNO3 ----> 3 Cu(NO3)2 (aq) + 2 NO (g) + 4 H2O(l)

3 eq of Cu reacts with 8 eq of HNO3

Moles of HNO3 = 3.5 mL *( 6 mol/ 1000 mL) => 0.021 mol

Molar mass of Cu = 63.54 g/mol

So 0.41 g / 63.54 g/mol => 0.00645 moles

For complete reaction of 0.00645 moles of Cu metal, we need 0.00645 mol * (8/3) = 0.017 mol of HNO3

but we have 0.021 moles of HNO3

Therefore Cu is the limiting reactant