Review 18

REVIEW QUESTIONS

Chapter 18

Calculate the heat of reaction ( ) in for the reaction shown below, given the values for each substance:

Given for the reaction shown below, calculate the for .

The air within a piston equipped with a cylinder absorbs 565 J of heat and expands from an initial volume of 0.10 L to a final volume of 0.85 L against a pressure of 1.0 atm . What is the change in the internal energy of the air within the piston?
How much work (in J ) is required to expand the volume of a pump by 2.5 L against an external pressure of 1.1 atm ?
Calculate the work associated with the following reaction at 1.00 atm and . Is the work done by the system or on the system?

The enthalpy change for vaporization of methanol at is . If the entropy of methanol vapor at is , what is the entropy of the liquid methanol at this temperature?
A reaction has and . At what temperature is the change in entropy for the reaction equal to the change in entropy for the surroundings?
Determine the entropy change ( ) in for the reaction shown below, given the standard entropies for each:
Given the following thermodynamic data, estimate the temperature ( ) at which the reaction shown below becomes spontaneous.

Calculate the free energy ( ) in kJ for the reaction shown below, given the values for each substance:
Methanol can be produced by the reaction shown below, with the following thermodynamic data given at .


-110.5	0	-238.6
-137.3	0	-166.2
+197.9		+126.8

a) Calculate

and

for this reaction.
b) Calculate

(in

) for this reaction.
c) Calculate

for hydrogen.
12. At

the equilibrium constant,

, for the reaction below is 0.281 atm .

a) What is

for this reaction?
b) If requires 193 J to vaporize 1.00 g of liquid bromine at

and 1.00 atm . Calculate

and

for this reaction.
c) Calculate the normal boiling point of bromine. Assume

and

are not affected by temperature. (Hint: At the normal boiling point liquid and vapor are in equilibrium)
13.

can be prepared by the reaction shown below:

a) Calculate the value of the equilibrium constant for this reaction at

.
b) Calculate

for this reaction at

.
c) If

produced were a liquid instead of a gas, how would the

for the reaction be different (sign and magnitude) than calculated above? Explain.
14. Production of ammonia from nitrogen and hydrogen gases is an important industrial reaction shown below:

a) Calculate

for this reaction at

. Assume

and

are not temperature dependent.
b) Calculate

for this reaction if the reaction mixture consists of 1.0 atm of

, 3.0 atm of

and 1.0 atm of

.
15. What are the signs of

and

for the sublimation of dry ice (solid

) at

?
16. Using the following data, calculate the value of

for

, one of the least soluble of the common nitrate salts.

Species

Show that hydrogen cyanide (HCN) is a gas at by estimating its normal boiling point from the following data:

	)
	108.9	113
	135.1	202