Lista 1 1 Lei da Termodinmica

Exerccios sugeridos do Atkins cap 2 8ed Exerccios -3, 8,14,18, 25; problema 5

1 - Consider an ideal gas that occupies 3.00 dm3 and has a pressure of 3.00 bar. This gas is

compressed isothermally at a constant pressure of Pext. Calculate the smallest value that Pext can

have if the final volume is 0.50 dm3. Using the value of Pext obtained, calculate the work done

on the gas.

(a) -4500 J

(b) 125 J

(c) 300 J

(d) 3225 J

(e) 3000 J

(f) 4500 J

2 - Calculate the work done when one mole of an ideal gas is compressed reversibly from 3.00

bar to 10.00 bar at a constant temperature of 300 K.

(a) 3002 kJ

(b) 2740 J

(c) 2494 kJ

(d) 3002 J

(e) 1,20 J

(f) 1,86 J

(g) 1,86 kJ

3 - Consider the reversible adiabatic expansion of one mole of an ideal gas from T1 and P1 to T2

and P2. What is the correct relationship between the temperatures, pressures, and the molar

constant pressure heat capacity, CP ?

4 - Given the following data,

H2(g) + F2(g) HF(g) rH = -273,3 kJ

H2(g) +O2(g) H2O(l) rH = -285,8 kJ

What is the value of rH for the reaction,

2F2(g) + 2H2O(l) 4HF(g) + O2(g) ?

(a) rH = -521,6 kJ

(b) rH = -11,7 kJ

(c) rH = -596,6 kJ

(d) rH = 1118,2 kJ

(e) rH = -1689,8 kJ

(f) rH = 559,1 kJ

5 - For a monatomic ideal gas

2

1

2/3

1

2

V

V

T

T

Now consider a diatomic gas, N2, at 298 K. This gas is compressed reversibly and adiabatically

from 15 dm3 to 5.0 dm

3. Assume that the heat capacity of this gas is CV = 5R/2, and that it

behaves ideally. Calculate the final temperature, T2, of the gas.

(a) 462 K

(b) 751 K

(c) 303 K

(d) 1033 K

(e) 433 K

6 - Calculate the work done in the isothermal reversible expansion of one mole of CH4(g)

from 1.00 dm3 mol

-1 to 10.00 dm

3 mol

-1 at 300 K. Treat methane as a van der Waals

gas. The van der Waals gas constants for methane are: a = 2,3026 dm6 .bar . mol

-2

and b = 0,043067 dm3 .mol

-1.

(a) -4100 J

(b) 5630 J

(c) -5,63 kJ

(d) -46,37 J

(e) -230,07 J

(f) -2,307 kJ

7 - Given the following data for water, determine vapH at 298 K :

vapH at 373 K = 40,7 kJ mol-1

CP (l) = 75,2 J mol-1

K-1

CP (g) = 33,6 J mol-1

K-1

(a) 43,8 J mol-1

(b) 149,3 J mol-1

(c) 149,3 kJ mol-1

(d) 48,9 J mol-1

(e) 40,7 kJ mol-1

(f) 48,9 kJ mol-1

(g) 43,8 kJ mol-1

Respostas: 1-a; 2-d; 3- pC

R

PP

TT

2

121 ; 4 a; 5-a;6-c;7-g