Question

REACTION OF COPPER AND ITS COMPOUNDS PRE-LABORATORY QUESTIONS The following preparatory questions should be answered before coming to lab. They are intended to introduce you to several ideas that are important to aspects of the experiment. You must turn in your work to your instructor before you will be allowed to begin the experiment. 1. Balance the three copper reactions: Cu(NO3)2 (aq) + NO2(g) + H2O (1) i) Cu (s) + HNO3(aq) ii) Cu(NO3)2 (aq) + NaOH(aq) Cu(OH)2 (s) + NaNO3(aq) Cuo(s) + H20 (1) iii) Cu(OH)2 (s) 2. In reaction (i), suppose you add 4.0 mL of 6 M nitric acid to a sphere of copper metal that weighs 0.65 grams. Which reactant is the limiting reagent? (Show your work) CHEM1814-YEAR 2019-2020 9-1

Answer 1

i Hi au 15) + 4HNO3(aq) -> Cu(NO3)2 (aq) + 2ND2.83 + 2H206). Cu(NO3)2 (20) 2NaOH AY) - Cu(OH), (8) + 2 NANO3(aq). Cu(OH)2.15) --- Cul (s) + H20 (1) ji . 4.0 ml of GoM nitric acid means the molarity of Nitric acid is 6 moles per litre / 1000 m ie 1000 mL salution contains 6 mole HNO3 1 ml solution contains 6 mole 1000 4.0 ml contains ces. 6 x 4.0 moles. 1000 0.024 miles of HNO3 - Malar mass of lu = 63.546 g/mole moles of ce in 0.65 g = 0.65 g - 63.546 g/mole = 0·10 22 88106 males. According to first balanced equation 1 mole Cu required 4 mole E HNO3 So, 0.1022 88106 mole Cu require 4X0.202288106 - 0.0409152425 i 0.63 g Cu require 0040915 2425 moles of HNO₃ but we have only 0.024 mole of HNO3 ,SO HNO₃ is limiting reagent