How many calories of heat are required to raise the temperature of 4 kg of water from 50F to the boiling point?
a. 6.5 105
b. 3.6 105
c. 15 105
d. 360
e. 4 104
[Ques. 2] Determine the heat capacity (in calories/C) of a lake containing one million gallons (approximately 4 million kilograms) of water at 15C.
a. 4 106
b. 4 109
c. 4 103
d. 1 103
e. 4 102
[Ques. 3] During the volcanic eruption of Mt. Pelee in 1902, an incredibly hot burning cloud rolled down the mountain and incinerated the town of Saint-Pierre. From the damage done, the temperature in the cloud was estimated at 700C. If the air temperature was 20C and a mole of air is 29 grams, estimate the molecular weight of the gas in the burning cloud that made it heavier than the surrounding air. (As a follow-on, estimate the most probable composition of the cloud. Some typical volcanic gases are H2S, SO2, H2SO4, CO2, NO.)
[Ques. 4] According to kinetic theory, a typical gas molecule in thermal equilibrium at room temperature has a kinetic energy K = 6.00 1021 J, regardless of mass. Estimate the speed at room temperature of a hydrogen molecule H2 (m = 3.34 1027 kg) and a xenon atom (m = 2.00 1025 kg). kB = 1.38 1023 J/K
[Ques. 5] A 50-gram sample of dry ice (solid CO2) is placed in a 4-liter container. The system is sealed and allowed to reach room temperature (20C). By approximately how much does the pressure inside the container increase when the dry ice turns to gas? (Ignore the initial volume of the sample.)
[Ques. 6] If CP for an ideal gas is 35.4 J/mol/K, which of the following is CV for this gas?
a. 12.5 J/mol/K
b. 20.8 J/mol/K
c. 29.1 J/mol/K
d. 27.1 J/mol/K
e. 43.4 J/mol/K
[Ques. 7] The root mean square speed of a gas molecule is greater than the average speed, because the former gives a greater weight to
a. lighter molecules.
b. heavier molecules.
c. lower speeds.
d. higher speeds.
e. more probable speeds.
[Ques. 8] One mole of hydrogen, one mole of nitrogen and one mole of oxygen are held in a 22.4 103 cm3 enclosed vessel at 20C. The pressure in the vessel, in N/m2, is
a. 109.
b. 304.
c. 326.
d. 1.09 105.
e. 3.26 105.
[Ques. 9] Two tanks of gas, one of hydrogen, H2, and one of helium, He, contain equal masses of gas. The gram-molecular mass of He is twice that of H2 . Both tanks of gas are at the same temperature, 293 K. Which statement(s) below is(are) correct when we ignore vibrational motion?
a. The total internal energy of the hydrogen is the same as that of the helium.
b. The total internal energy of the hydrogen is 167 times that of the helium.
c. The total internal energy of the helium is 1.67 times that of the hydrogen.
d. The total internal energy of the hydrogen is 3.33 times that of the helium.
e. The total internal energy of the helium is 3.33 times that of the hydrogen.
[Ques. 10] Two tanks of gas, one of hydrogen, H2, and one of helium, He, contain equal numbers of moles of gas. The gram-molecular mass of He is twice that of H2 . Both tanks of gas are at the same temperature, 293 K. Which statement(s) below is(are) correct when we ignore vibrational motion?
a. The total internal energy of the hydrogen is the same as that of the helium.
b. The total internal energy of the hydrogen is 1.4 times that of the helium.
c. The total internal energy of the helium is 1.4 times that of the hydrogen.
d. The total internal energy of the hydrogen is 1.67 times that of the helium.
e. The total internal energy of the helium is 1.67 times that of the hydrogen.
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