11. Calculate the change in the Gibbs energy and molar Gibbs energy of 1.0 dm3 o
ID: 698689 • Letter: 1
Question
11. Calculate the change in the Gibbs energy and molar Gibbs energy of 1.0 dm3 of octane (liquid) when its pressure is acting on the liquid is increased from 1.00 atm to 100 atm. The mass density of octane is 0.703 g cm3 12. Calculate the molar quantiies AUAHAGm for the isothermal expansion of argon gas at 500 K from 1.0 L to 3.0 L. Assume that argon behaves ideally. 13. When a Tootsie Roll is burned in a calorimeter at 298 K and constant pressure, the resulting combustion of sucrose raised the temperature of the calorimeter (Ceal 6.25 kJ K) from 23.42 C to 74.67 C. Based on this result, (a) calculate the standard molar enthalpy of the reaction, (b) calculate the enthalpy of this reaction, and (c) what is the mass of sucrose in a Tootsie Roll? Use thermodynamic tables to demonstrate your answer. 14. On a hot summer day, 1.5 kg block of ice is left on a picnic table, where it is spontaneously transforms into a pool of water in thermal equilibrium with the surroundings. Assuming that the temperature of the surroundings remains constant at 34.6 C throughout the process, calculate the S for the transformation. Some of the following data for water may be useful: A,apH-40.656 kJ mol-1 at T = 373.15 K Am,H = 6.008 kJ mol-1 at T = 273.15 K Cp (liquid water) = 4.18 J K.1g-I Cp (solid water) = 2.03 J K'g 15. Calculate the enthalpy of formation of CaO(s) from its elements at 298.15 K.Explanation / Answer
Change in gibbs energy for a liquid is
Delta G = V (Pf - Pi), v is volume, pf and pi are final and initial pressure, G is gibbs
The first thing to do is to change units to pascals and dm3 to m3
1 dm3 is 0.001 m3
1 atm = 101325 Pa
100 atm = 10132500 Pa
Delta G = 0.001 * (10132500 - 101325 ) = 10031.175 Joules or 10.031 KJ
For molar gibbs energy we must calculate the number of moles
we have volume and density mathematically if we multiply this 2 we will get mass
first change 1 dm3 to cm3 which is 1000 cm3
mass = 1000 * 0.703 = 703 grams of octane
octane has a molar mass of 114.23 g/gmol
moles = mass / molar mass
moles = 703 / 114.23 = 6.15 moles
molar gibbs energy = 10.031 KJ / 6.15 moles = 1.631 KJ / mole
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.