need help with these 2 questions. please show the steps you took. 12. Mg (s) + 2

Question

need help with these 2 questions. please show the steps you took.

12. Mg (s) + 2 HCl (aq) MgCl2 (aq) + H2 (g) Find the amount of work done and change in internal energy, E at 25°C and 1 atm pressure when 2.50 g of Mg is reacted with excess HCI as per the above equation. Include proper units in your final answer. work done 1° =-350 kJ/mol. 13. Calculate the standard enthalpy of formation of carbon disulfide (CS2) from its elements, given that C (graphite) + O2 (g) CO2 (g) S (rhombic) + O2 (g) SO2 (g) CS2 (I) + 3 O2 (g) CO2(g) + 2 SO2 (g) AHn 393.5 kJ/mol AHoxn 296.4 kJ/mol AH"m--1073.6 kJ/mol Answer:k kJ/mol

Explanation / Answer

12.

DH = DE+PDV

No of mol of Mg = 2.5/24 = 0.104 mol

PDV = DnRT = (0.104-0)*8.314*298 = 257.7 joule = 0.257 kj

workdone = 0.257 kj

DH0 = -350*0.104 = -36.4 kj

-36.4 = x+0.257

x = -36.657 kj = DE

13.

DHrxn = DHfco2 + 2*DHFso2 - DHfCS2 + 3*dhFo2

   -1073.6 = (-393.5-2*296.4) - (x + 3*0)

x = DHfCS2 = 87.3 Kj/mol

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