Question

QuesL # Deductions ol OL Total Constant Current System # Laboratory Temperature: Atmospheric Pressure: 2200 710.9 mm the Water Vapour Pressure (Show calculation below) 19.8 mmHg Reading Mass of copper (8) Time (sec) Height of water column mm Current (A) 0.35 10.135 Burette reading (ml) 2.10 37.12 35,02 133.0 Initial Final Change Initial Run 1 3.343 3.305 0.088 3,305 1837 1837 AVERAGE: 0.135 0.134 99.4 Run 2 Final 3. 222 9.50 0 38.47 1 1800 33.91 1800 0.132 Change 0.083 AVERAGE: 0.133

i need help with these questions.

Answer 1

Cu + 2H+ (aq) ===> Cu2+ (aq) + H2 (g)

#1 . moles of H2 produced , form PV = nRT

n = PV/RT

P = 710.9 / 760 mmHg/atm = 0.9354 atm

n = 0.9354 atm *0.03502 L / 0.0821 L-atm/K-mol * 295.15 K = 1.35*10-3 moles

1 mol of H2 = 1 mol of Cu

moles of Cu consumed = 1.35*10-3 moles

similarly , trial #2 : moles of Cu consumed = 1.31*10-3 moles

==

#2.

#1. Number of coulombs = current in amps x time in seconds = 0.135 A * 1837 s = 247.96 C

   1 mole of H2 = 2 mol of electrons

moles of Electrons : 2.7*10-3 moles

thus, Faraday = 247.96 C/ 2.7*10-3 moles=   91,837 C/mol

#2 :    Faraday =     91,375 C/mol

=====

#3    #1 atomic mass of Cu : mass of Cu consumed / moles of Cu consumed = 0.088 g/ 1.35*10-3 moles = 65.2 g/mol

      #2 . atomic mass of Cu : 63.4 g/mol

==

#4   AVERAGE value Faraday : 91606 C/mol

% error : / 96488 - 91606 / / 96488 *100 = 5.06 %