Pre-Test II

Name______

1) An automobile tire has a volume of 0.0185 m3. If the pressure in the tire is 500 kPa and the temperature is 298 K, how many molecules are there inside the tire? A) 2.25 × 1023 B) 2.25 × 1024 C) 3.25 × 1023 D) 3.25 × 1024 Answer: B

2) A 20.0-L pressure vessel holds 2.00 moles of oxygen at 30ºC. What is the pressure inside the vessel? A) 101 kPa B) 1.01 × 106 Pa C) 2.52 × 106 Pa D) 252 kPa Answer: D

3) On a cold day, you take in 4.2 L of air into your lungs at a temperature of 0ºC. If you hold your breath until the temperature of the air in your lungs reaches 37ºC, what is the volume of the air in your lungs at that point, assuming the pressure does not change? A) 4.4 L B) 4.6 L C) 4.8 L D) 5.0 L Answer: C

4) The coefficient of linear expansion of aluminum is 24 × 10-6 K-1 and the coefficient of volume expansion of olive oil is 0.68 × 10-6 K-1. A novice cook, in preparation for deep-frying some potatoes fills a 1.00-liter aluminum pot to the brim and heats the oil and the pot from an initial temperature of 15°C to 190°C. To his consternation some olive oil spills over the top. How much? A) 0.11 liters B) 0.12 liters C) 0.13 liters D) 0.14 liters Answer: A

5) A block of metal is 2 cm × 3 cm × 5 cm. When one of the 2 cm × 3 cm faces is held at a temperature T1 and the other at a temperature T2, the heat flow through the block is P. In terms of P, what is the heat flow when one of the 3 cm × 5 cm faces is held at a temperature T1 and the other at a temperature T2? A) (9/4)P B) (9/25)P C) (75/12)P D) (25/9)P Answer: C

6) When you walk barefoot in a room, the floor feels cooler walking on a tile floor as compared to a wooden floor because A) tile has a smaller specific heat than wood. B) tile has a larger specific heat than wood. C) tile has a smaller thermal conductivity than wood. D) tile has a larger thermal conductivity than wood. Answer: D 7) The type of heat transfer that occurs between the radiator of a car and the atmosphere, when the car is in motion, is principally A) convective. B) conductive. C) radiative. D) countercurrent. Answer: A

8) Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are given the same amount of heat. If the temperature of Object 1 changes by an amount DT , the change in temperature of Object 2 will be A) DT . 3 B) DT . 4 4 C) DT . 3 D) 12DT . Answer: D

9) What is the internal energy in 2.7 moles of hydrogen at 300 K? As an approximation, treat the hydrogen gas as if it was monatomic. A) 10 kJ B) 12 kJ C) 14 kJ D) 18 kJ Answer: A

10) If you add 1.73 MJ of heat to 700 g of water at 70ºC, what is the final temperature of the steam? The latent heat of vaporization of water is 22.6 × 105 J/kg. The specific heat of steam is 2010 J/(kg K). A) 100ºC B) 123ºC C) 147ºC D) 143ºC Answer: D

11) A 48.0-g block of ice at -15.0ºC is dropped into a calorimeter containing water at 15.0ºC. When equilibrium is reached, the final temperature is 8.0ºC. How much water did the calorimeter contain initially? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 302 g B) 405 g C) 655 g D) 634 g Answer: C

12) On a hot summer day, you turn the thermostat in your house way down. Assume that your house is well sealed and that no air enters or leaves the house. When the air temperature in your house falls a short while later, what statement is correct regarding the air pressure? A) The air pressure is higher at the lower temperature. B) The air pressure is lower at the lower temperature. C) The air pressure does not change at the lower temperature. D) The air pressure decreases at first but then increases again as the temperature approaches its lower value. Answer: B

13) Two containers of equal volume each hold samples of the same ideal gas. Container A has twice as many molecules as container B. If the gas pressure is the same in the two containers, the correct statement regarding the absolute temperatures TA and TB in containers A and B, respectively, is A) TA = TB. B) TA = 2TB. 1 C) TA = T . 2 B 1 D) TA = TB . 2 Answer: C

14) A laboratory vacuum pump can reduce the pressure to 1.0 × 10-7 Pa. If the volume of the chamber is 0.500 m3 and the temperature is 27ºC, how many molecules are left inside the chamber? A) 1.2 × 1013 B) 2.4 × 1013 C) 1.2 × 1012 D) 2.4 × 1012 Answer: A

15) A vertical cylindrical cylinder, closed at the bottom end, is fitted at the top with a piston, which can move freely. The mass of the piston is 10.0 kg and the initial height of the piston above the bottom of the cylinder is 25 cm. A mass of 8 kg is placed on the piston. What is the resulting height of the piston, assuming that the temperature is kept constant? A) 12 cm B) 13 cm C) 14 cm D) 15 cm Answer: C

16) What is the root mean square value of the following speeds: 2.0 m/s, 3.0 m/s, 4.0 m/s? A) 2.8 m/s B) 2.9 m/s C) 3.0 m/s D) 3.1 m/s Answer: D

17) If you double the absolute temperature of an ideal gas, the rms value of the speed of the molecules A) doubles. B) quadruples. C) is multiplied by 2 . D) is multiplied by 1/ 2 . Answer: C

18) The rms speed of a certain sample of carbon dioxide molecules, with a molecular weight of 44 g/mole, is 396 m/s. What is the rms speed of water molecules, with a molecular weight of 18 g/mol, at the same temperature? A) 253 m/s B) 421 m/s C) 506 m/s D) 619 m/s Answer: D

19) A 50-kg air conditioner is placed on top of a concrete pad with a cross-sectional area of 3.0 m2 and 20 cm thick. What is the change in thickness of the pad? Young's modulus for concrete is 2.3 × 1010 N/m2. A) 1.4 × 10-9 m B) 2.8 × 10-9 m C) 1.4 × 10-8 m D) 2.8 × 10-8 m Answer: A

20) If you add 800 kJ of heat to 800 g of water at 80.0ºC, how much water is left in the container? The latent heat of vaporization of water is 22.6 × 105 J/kg. A) 476 g B) 258 g C) 600 g D) none Answer: A

21) When both the pressure and the absolute temperature of an ideal gas are increased each by a factor of two, the volume occupied by the gas will A) increase by a factor of four. B) increase by a factor of two. C) not change. D) decrease by a factor of four. Answer: C

22) A quantity of an ideal gas is kept in a rigid container of constant volume. If the gas is originally at a temperature of 19ºC, at what temperature will the pressure of the gas double from its base value? A) 91ºC B) 38ºC C) 311ºC D) 273ºC Answer: C

23) What is the average kinetic energy of a nitrogen molecule in the air in a room in which the air temperature is 17.0°C? A) 6.01 × 10-21 J B) 4.00 × 10-21 J C) 5.00 × 10-21 J D) 7.00 × 10-21 J Answer: A

24) In a city high in the mountains, such as Denver, CO, water boils A) at the same temperature as it does at sea level. B) at a higher temperature than it does at sea level. C) at a lower temperature than it does at sea level. D) at a higher temperature than it does at sea level in the morning but at a lower temperature than it does at sea level the rest of the day. Answer: C

25) On a cold winter day, you turn up the thermostat in your house. Assume that your house is well sealed and that no air enters or leaves the house. When the air temperature in your house rises a short while later, what statement is correct regarding the air pressure? A) The air pressure is higher at the higher temperature. B) The air pressure is lower at the higher temperature. C) The air pressure does not change at the higher temperature. D) The air pressure increases at first but then decreases again as the temperature approaches its higher value. Answer: A