Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1) Calculate Delta Srxn for 2Mg( s )+O2( g )?2MgO( s ) (Please show work) 2) Fir

ID: 847951 • Letter: 1

Question

1) Calculate Delta Srxn for 2Mg(s)+O2(g)?2MgO(s) (Please show work)

2) Firefly luciferase is the enzyme that allows fireflies to illuminate their abdomens. Because this light generation is an ATP-requiring reaction, firefly luciferase can be used to test for the presence of ATP. In this way, luciferase can test for the presence of life. The coupled reactions are

luciferin+O2ATP??oxyluciferin+lightAMP+PPi

If the overall ?G of the coupled reaction is -6.70kJ/mol , what is the equilibrium constant, K, of the first reactions at 278K? The ?G for the hydrolysis of ATP to AMP is ?31.6 kJ/mol.

3) At 25?C the reaction from Part A has a composition as shown in the table below.

Substance Pressure
(atm) C2H2(g) 5.55 H2(g) 5.65 C2H6(g) 4.25

Explanation / Answer

1. Answer

2Mg(s)+O2(g)?2MgO(s)

delta So = (delta Ho - delta Go) / T

delta H0 = 2*deltaH0 f = 2 mol * ( - 602 ) = -1204 kj/mol
delta G0 = 2* delta G0 f = 2 mol * ( -569.6) = - 1139.2 kj / mol

delta S0 = [ -1204 - ( - 1139.2 ) ] / 298 = - 218.121 j/k-mol

2. Overall DeltaG = -6.40 kJ/mol

Delta G = 31.6 - 6.4 =25.2 KJ

T = 17 + 273.15 =290.15 K

Delta G = -RT * Ln (K)


25.2 * 10^3 J = -(8.314 J/moles*k)(290.15K) * Ln (K)

So (Delta G)/(-RT) = Ln (K)

Ln K = -10.44643114

Thus k = 2.905 *10^-5