Chemical Thermodynamics and Energetic - Work, Heat, Energy, Extensive and Intensive Properties

What is the action of heat on potassium permanganate?

Absolute entropies of solids, liquids and gases can be determined by

• Measuring heat capacity of substance at various temperatures
• Subtracting standard entropy of reactants from products
• Measuring vibrational motion of molecules
• Using formula ΔS° = S_T° - S_O°

Determine whether the reactions with the following ΔH and ΔS values are spontaneous or non-spontaneous. State whether the reactions are exothermic or endothermic.

(a) ΔH = -110kJ, ΔS = + 40JK^-1 at 400 K

(b) ΔH = + 40kJ, ΔS = -120JK^-1 at 250K

One mole of a gas expands by 3L against a constant pressure of 3 atmosphere. Calculate the work done in -

(a) L.atmosphere

(b) Joules

(c) Calories

For a certain reaction, ∆H = − 50 kJ and ∆S = − 80 J K^-1, at what temperature does the
reaction turn from spontaneous to non-spontaneous?

(A) 6.25 K

(B) 62.5 K

(C) 625 K

(D) 6250 K

55 L atm of work is obtained when 1.0 mole of an ideal gas is compressed isothermally from
a volume of 28.5 L to 18.5 L, the constant external pressure is

(A) 5.05 atm

(B) 5.5 atm

(C) 0.05 atm

(D) 0.55 atm

Which of the following pairs is an intensive property?

(A) Density, viscosity

(B) Surface tension, mass

(C) Viscosity, internal energy

(D) Heat capacity, volume

Derive the equation : W = - P_extAV