TERMODINMICA
LISTA DE EJERCICIOS No1
WILLIAM OSWALDO SOSA CORREA
Universidad Pedag´ogica y tecnol´ogica de Colombia.
1. La bola de fuego de una explosi´on nu-
clear de 1.0 megat´o alcanza una temper-
atura La temperatura de 7000 K. Con-
tiene gas ionizado y electrones libres.
Cu´al es la velocidad rms (vrms =√¯v)
y la energ´ıa cin´etica promedio de free
electrones en la bola de fuego? Cu´ales
son la velocidad rms y el energ´ıa cin´etica
promedio de iones de nitr´ogeno?
2. Una bomba de bicicleta es un cilindro de
2.5 cm de di´ametro y largo 30 centimet-
ros. Inicialmente, cuando el pist´on est´a
completamente extra´ıdo, el el cilindro se
llena con aire a 25 0Cy 1.0 atm. Si
lentamente comprime el aire a la mitad
de su volumen inicial, qu´e fuerza debe
ejercer sobre el pist´on para mantenerlo
en la posici´on comprimida? Supong-
amos que la temperatura del aire per-
manece constante y que la v´alvula est´a
bloqueada, por lo que no escapa el aire.
3. Suppose you heat 1.00 kg of water and
convert it into steam at the boiling tem-
perature of water, 373 K, and at normal
atmospheric pressure, 1.00 atm. What
is the volume of the steam?
4. Hot-air balloons become buoyant when
the gas inside is heated with a burner
below the balloon. If the temperature
of the gas is increased to 50 0C(at con-
stant pressure), what is the mass of the
gas that remains in the balloon? What
mass can be lifted by the balloon?. Hint:
Use the data of the example shown in
the class.
5. La reacci´on de un centavo de cobre con
´acido n´ıtrico da como resultado la for-
maci´on de un compuesto gaseoso marr´on
rojizo que contiene nitr´ogeno y ox´ıgeno.
Una muestra del gas a una presi´on de
727 mm-Hg y una temperatura de 18 0C
pesa 0.289 g en un matraz con un volu-
men de 157.0 mL. Calcule la masa molar
del gas y sugiera una f´ormula qu´ımica
razonable para el compuesto.
6. A diving bell is a cylinder closed at the
top and open at the bottom; when it is
immersed in the water,any air initially
in the cylinder remains trapped in the
cylinder. Suppose that such a diving
bell, 2.0mhigh and 1.5macross, is
initially full of air and is immersed to
a depth of 15 mmeasured from water
level to water level (see fig. 1).
(a) How high will the water have risen
within the diving bell?
(b) If compressed air is pumped into
the bell,water will be expelled from the
bell.How much air (in kilograms) must
be pumped into the bell,and at what
pressure,to get rid of all of the water?
Assume that the temperature of the air
is 15 0C.
7. At high altitudes, pilots and mountain
climbers must breathe an enriched mix-
ture containing more oxygen than the
standard concentration of 23 % found
in ordinary air at sea level.At an alti-
tude of 11000 m,the atmospheric pres-
sure is 0.24 atm. What oxygen concen-
tration is required at this altitude if with
each breath the same number of oxygen
molecules is to enter the lungs as for or-
dinary air at sea level?
