Seminar assignments - homework assignment 11 - questions + answers PDF

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Homework Assignment 11 - questions + answers...

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cadena (jc59484) – Homework #11 – reichl – (58305)

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This print-out should have 21 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering.

the temperature of 160 grams of water from 26 ◦C to 80 ◦C. The specific heat of water is 4.18 J/g ·◦ C. Answer in units of J

001 10.0 points The brick wall (of thermal conductivity 0.57 W/m ·◦ C) of a building has dimensions of 2.5 m by 9 m and is 24 cm thick. How much heat flows through the wall in a 8.9 h period when the average inside and outside temperatures are, respectively, 31 ◦ C and 8◦ C? Answer in units of MJ

006 (part 1 of 2) 10.0 points A cylinder contains 4.76 mol of helium gas at a temperature of 327 K. The molar specific heat of helium at constant volume is 12.5 J/K mol. How much heat must be transferred to the gas to increase its temperature to 523 K if it is heated at constant volume? Answer in units of J

002 10.0 points What is the final equilibrium temperature when 12 g of milk at 23◦ C is added to 156 g of coffee at 89◦ C? Assume the specific heats of milk and coffee are the same as that of water, and neglect the specific heat of the container. Answer in units of ◦C

007 (part 2 of 2) 10.0 points The molar specific heat of helium at constant presure is 20.8 J/K mol. How much thermal energy must be transferred to the gas at constant pressure to raise the temperature to 523 K? Answer in units of J

003 10.0 points An ideal gas is held in a container at constant volume. Initially, its temperature is 5◦C and its pressure is 2.2 atm. What is its pressure when its temperature is 116◦ C? Answer in units of atm

008 10.0 points A styrofoam container used as a picnic cooler contains a block of ice at 0◦ C. If 287 g of ice melts in 1 hour, how much heat energy per second is passing through the walls of the container? The heat of fusion of ice is 3.33 × 105 J/kg. Answer in units of W

004 10.0 points If the gas in a container absorbs 275 Joules of heat, has 125 Joules of work done on it, then does 50 Joules of work, what is the increase in the internal energy of the gas? 1. ∆U = 350 J 2. ∆U = 400 J

009 10.0 points How much energy is required to change a 39 g ice cube from ice at −13◦ C to steam at 116◦ C? The specific heat of ice is 2090 J/kg ·◦ C, the specific heat of water is 4186 J/kg ·◦ C, the specific heat of stream is 2010 J/kg ·◦ C, the heat of fusion is 3.33 × 105 J/kg, and the heat of vaporization is 2.26 × 106 J/kg. Answer in units of J

3. ∆U = 450 J 4. ∆U = 100 J 5. ∆U = 200 J 005 10.0 points Calculate the amount of heat required to raise

010 10.0 points What is the Celsius temperature corresponding to the normal temperature 98.6◦ F of the human body? 1. 36.2◦ C

cadena (jc59484) – Homework #11 – reichl – (58305) 2. 37◦C 3. 40◦C 4. 35.1◦ C

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into an open fire. When the temperature of the air in the bottle reaches 168◦C, what is the pressure inside the bottle? Assume any volume changes of the bottle are negligible. Answer in units of kPa

5. 38.4◦ C 6. 39.1◦ C 011 (part 1 of 2) 10.0 points An air bubble originating from an underwater diver has a radius of 7 mm at some depth h. When the bubble reaches the surface of the water, it has a radius of 9.8 mm. Assuming the temperature of the air in the bubble remains constant, determine the depth of the diver. The acceleration due to gravity is 9.8 m/s2 . Answer in units of m 012 (part 2 of 2) 10.0 points Determine the absolute pressure at this depth. Answer in units of kPa 013 10.0 points How much heat is needed to vaporize 100 g of water at 100◦C? The specific heat of water is 1 cal/g◦C, its heat of vaporization is 540 cal/g and its heat of fusion is 80 cal/g. 1. None of these 2. 10000 cal

015 10.0 points William burns 2.6 g of peanuts beneath 1000 g of water, which increases in temperature from 30◦C to 48◦ C. Assuming 35% efficiency, what is the food value of the peanut? Answer in units of cal 016 10.0 points When water freezes 1. heat is absorbed from the surroundings. 2. there is no heat exchange with the surroundings. 3. the temperature of the water increases. 4. heat is given off to the surroundings. 5. the temperature of the water decreases. 017 10.0 points The internal energy of the gas in a gasoline engine’s cylinder decreases by 172.9 J. If 26.0 J of work is done by the gas, how much energy is transferred as heat? Answer in units of J

3. 100 cal 4. 5400000 cal 5. 54000 cal 6. 80 cal

018 (part 1 of 2) 10.0 points The lowest outdoor temperature ever recorded on Earth was −128.6◦F, recorded at Vostok Station, Antarctica, in 1983. What is this temperature on the Celsius scale? Answer in units of ◦ C

7. 800 cal 014 10.0 points A sealed glass bottle containing air at atmospheric pressure (101 kPa) and having a volume of 44 cm3 is at 27◦ C. It is then tossed

019 (part 2 of 2) 10.0 points What is this temperature on the Kelvin scale? Answer in units of K 020

10.0 points

cadena (jc59484) – Homework #11 – reichl – (58305) A gas is enclosed in a container fitted with a piston. The applied pressure is maintained at 610.9 kPa as the piston moves inward, which changes the volume of the gas from 5.336 × 10−4 m3 to 2.795 × 10−4 m3. How much work is done? Answer in units of J 021 10.0 points A cylinder with a movable piston contains gas at a temperature of 12.1 ◦C, a volume of 1.9 m3, and an absolute pressure of 14300 Pa. What will be its final temperature if the gas is compressed to 0.55 m3 and the absolute pressure increases to 60990 Pa? Answer in units of ◦C

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