Question

Review Consta The chemical reaction that causes aluminum to corrode in air is given by 4Al +30, +2A1,03 in which AH - - 3352 kJ/mol ASM = 625.1 J/(mol-K) What is the standard Gibbs free energy for this reaction? Express your answer as an integer and include the appropriate units. View Available Hints) AG. = -6727540 ) Submit Previous Answers X Incorrect; Try Again: 2 attempts remaining Enter your answer using units of enthalpy Part B What is the Gibbs free energy for this reaction at 5400 K ? Assume that AH and AS do not change with temperature Express your answer to two decimal places and include the appropriate units. View Available Hint(s) " ROO? AGE Acim- 6727540 1-6727540 kg kg Type here to search

Answer 1

A)

ΔHo = -3352.0 KJ/mol

ΔSo = -625.1 J/mol.K

= -0.6251 KJ/mol.K

T = 298 K

use:

ΔGo = ΔHo - T*ΔSo

ΔGo = -3352.0 - 298.0 * -0.6251

ΔGo = -3165.7202 KJ/mol

Answer: -3166 KJ/mol

B)

Now we have:

ΔHo = -3352.0 KJ/mol

ΔSo = -625.1 J/mol.K

= -0.6251 KJ/mol.K

T = 5400 K

use:

ΔG = ΔHo - T*ΔSo

ΔG = -3352.0 - 5400.0 * -0.6251

ΔG = 23.54 KJ/mol

Answer: 23.54 KJ/mol