#8 exp. 32 please help me do #8 7. A Mg Mg2 12H Ha galvanic cell generates a cur

Question

#8 exp. 32

please help me do #8

7. A Mg Mg2 12H Ha galvanic cell generates a current of 2.15x 10 2 amperes for 205 minutes and, in the process, 29.9 mL of hydrogen at STP are collected. Calculate the values of Avogadro's number and the Faraday, assuming the charge on an electron is 1.602x10 19 coulombs/electron One Faraday is the electn charge per mole of electrons It is given by 26.4. coulombs 1mol H. 0.0013 Brnoi 2mol.e 9.94 x 10 coulombs/mol 2 Therefore, 1 Faraday 9.94 x 104 coulomb charge carried by one electron is 1.602 x 10 Hence. Avogadro number ino. of electrons in 9.94 x 10 coulombs lelectron. 6.207x10 electrons mole 1.602 x 10 19 coulombs lmaole Avagadro number 6.207 x 1023panicles per mole 8. Calculate the mass thc magnesium anode should have lost during the process in #7.

Explanation / Answer

Mg --> Mg+2   +2e

2H+ +2e --> H2

so when one mole of hydrogen gas is evolved one mole of Mg get lost from anode

as we have collected 22.9mL so lets calcualte the moles of hydrogen evolved

22.4 L is occupied by one mole of a gas

so 22.9 mL will be occupied by 22.9mL X 1/ 22.4 L = 0.001 moles

so magneium lost = 0.00102 moles

At wt of magnesium = 24g

so mass of magnesium lost = 24 X 0.001 = 0.0245g

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