Mass of copper anode Mass of anode after electrolysis Mass loss of copper anode

Question

Mass of copper anode Mass of anode after electrolysis Mass loss of copper anode Initial buret reading Final buret reading Volume of H; produced Reaction temperature Barometric pressure reading Vapor pressure of H:0 at reaction temp. Pressure of dry H_2 Results - Gram Equivalent Mass From Hydrogen Gas Data Mass loss to copper anode (from above) Moles of H_2: (from Ideal gas Law) Moles of electrons (Faradays) passing through cells Experimental gram equivalent mass of Cu (from gas P, V. T data) Actual gram equivalent mass of Cu Percent error in experimental value from H_2 data Results - Gram Equivalent Mass From Coulometry Data Mass loss of copper anode (from above) Number of Faradays passing through cell (from coulometry data) Experimental gram equivalent mass of Cu (from coulometry data) Actual gram equivalent mass of Cu (from above) Percent error in experimental value from coulometry data Include in your report, on a separate sheet, one sample calculation of each quantity marked with an asterisk

Explanation / Answer

Gram Equivalent Mass from Hydrogen Data.

Moles of H2

PV = nRT

P = 0.785 atm

V = 91 mL

T = 298 K

n = 0.0785 atm x 91 x 10-3 L / 8.205 74 × 10 2 L atm K1 mol1 x 298 K

n = 0.0029213 mol

Moles of electron passed through the cell

Total coulombs = 649.9 C

Charge of 1 mole of electron is 96485.3383 C

Charge 1 mole of electron = 96485.3383 C

649.9 C = 649.9 / 96485.3383 mol of electron

Moles of electron passed through the cell is 0.0067357.

Anode : Cu ---> Cu2+ + 2e-

Cathode : 2H+ + 2e- ------> H2(g)

Cu + 2H+ -----> H2

So number of moles of Cu is 0.0029213

Molar mass of Cu is 63.5460 g/mol

Mass = 0.0029213 x 63.5460 g/mol

= 0.185 g

Experimental gram equivalent mass of cu = 0.185 g

Percentage error

= | #Experimental - #theoretical / #theoretical | x 100

= 0.016 / 0.169 X 100

Percentage error 9.46 %

Result form coulometric Data.

1 Faraday = Charge 1 mole of electron = 96485.3383 C

1 C = 1 / 96485.3383 Faraday

649.9 C = 649.9 / 96485.3383 Faraday

0.006735 Faraday

2 moles of electrons produces 1 moles of H2

2 moles of electrons = 1 moles of H2

0.006735 of electrons = 1/2 x 0.006735 moles of H2

0.003367 moles of H2

So number of moles of Cu is 0.003367

Mass of Cu = 0.003367 x 63.5460 g/mol

= 0.2140 g

Percentage error

= 0.214-0.169 / 0.169 x 100

Percentage error is 26.62%

Related Questions

Navigate

• Browse (All)
• Browse M
• Subjects

---