/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q. 1.41. Problem 1.41. To measure the hea... [FREE SOLUTION] | 91影视

91影视

Problem 1.41. To measure the heat capacity of an object, all you usually have to do is put it in thermal contact with another object whose heat capacity you know. As an example, suppose that a chunk of metal is immersed in boiling water (100掳C), then is quickly transferred into a Styrofoam cup containing 250 g of water at 20掳C. After a minute or so, the temperature of the contents of the cup is 24掳C. Assume that during this time no significant energy is transferred between the contents of the cup and the surroundings. The heat capacity of the cup itself is negligible.

  1. How much heat is lost by the water?
  2. How much heat is gained by the metal?
  3. What is the heat capacity of this chunk of metal?
  4. If the mass of the chunk of metal is 100 g, what is its specific heat capacity?

Short Answer

Expert verified
  1. The heat gained by water is 1000 cal.
  2. -1000 cal.
  3. 13.157鈥塩补濒.碍-1
  4. The specific heat of 100 g of a chunk of the metal is c=0.131cal.g-1K-1.

Step by step solution

01

Part a. Step 1. Given.

Mass of water,m=250g

Specific heat of water,c=1鈥塩补濒.驳-1K-1

Initial temperature,T1=240C

Final temperature,T2=200C

02

Part a. Step 2. Calculation.

The first energy transfer takes place between the chunk of metal and the boiling water at temperature 1000C. The next energy transfer takes place between the metal and the water in the Styrofoam cup that was at temperature 200C.

The heat absorbed Qby the water from the hot metal is given by the expression,

Q=mcT2T1Q=25014Q=1000鈥塩补濒

03

Part a. Step 3. Conclusion.

The only energy transfer is heat transfer, thus the heat absorbed by the water is 1000 cal.

04

Part b. Step 1. Introduction.

Heat capacity 鈥 It is defined as the ratio of heat absorbed to the change in the temperature.

Specific heat 鈥 It is the heat that is needed to raise the temperature of a unit mass to10C.

Energy transfer between two bodies is due to the difference in temperature of the bodies.

05

Part b. Step 2. Explanation.

The heat transfer takes place until the two bodies acquire an equilibrium state and the amount of heat absorbed by water is equal to the heat lost by the metal.

06

Part b. Step 3. Conclusion.

The heat lost by the metal is the heat absorbed by the water, that is -1000 cal.

07

Part c. Step 1. Given.

Initial temperature,T1=1000C

Final temperature,T2=240C

Amount of energy gained by the chunk,Q=1000cal

08

Part c. Step 2. Calculation.

The heat capacity of the metal is given by the expression,

C=QT2T1C=100024100=100076=13.157calK-1

09

Part c. Step 3. Conclusion.

The heat capacity of the metal chunk is calculated as C=13.157cal.g-1K-1.

10

Part d. Step 1. Given.

Heat capacity of the metal,C=13.157calK-1

Mass of the metal,m=100鈥塯

11

Part d. Step 2. Calculation.

c=Cmc=13.157100c=0.131cal.g-1K-1

12

Part d. Step 3. Conclusion.

Specific heat capacity of the 100 g mass of metal is calculated as c=0.131cal.g-1K-1.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Make a rough estimate of how far food coloring (or sugar) will diffuse through water in one minute.

At the back of this book is a table of thermodynamic data for selected substances at room temperature. Browse through the CPvalues in this table, and check that you can account for most of them (approximately) using the equipartition theorem. Which values seem anomalous?

If you poke a hole in a container full of gas, the gas will start leaking out. In this problem, you will make a rough estimate of the rate at which gas escapes through a hole. (This process is called effusion, at least when the hole is sufficiently small.)

  1. Consider a small portion (area = A) of the inside wall of a container full of gas. Show that the number of molecules colliding with this surface in a time interval tis role="math" localid="1651729685802" PAt/(2mvx), where width="12" height="19" role="math">Pis the pressure, is the average molecular mass, and vxis the average xvelocity of those molecules that collide with the wall.
  2. It's not easy to calculate vx, but a good enough approximation is (vx2)1/2, where the bar now represents an average overall molecule in the gas. Show that (vx2)1/2=kT/m.
  3. If we now take away this small part of the wall of the container, the molecules that would have collided with it will instead escape through the hole. Assuming that nothing enters through the hole, show that the number Nof molecules inside the container as a function of time is governed by the differential equation
    dNdt=A2VkTmN
    Solve this equation (assuming constant temperature) to obtain a formula of the form N(t)=N(0)et/r, where ris the 鈥渃haracteristic time鈥 for N(and P) to drop by a factor of e.
  4. Calculate the characteristic time for gas to escape from a 1-liter container punctured by a 1-mm2? hole.
  5. Your bicycle tire has a slow leak so that it goes flat within about an hour after being inflated. Roughly how big is the hole? (Use any reasonable estimate for the volume of the tire.)
  6. In Jules Verne鈥檚 Around the Moon, the space travelers dispose of a dog's corpse by quickly opening a window, tossing it out, and closing the window. Do you think they can do this quickly enough to prevent a significant amount of air from escaping? Justify your answer with some rough estimates and calculations.

The Fahrenheit temperature scale is defined so that ice melts at 320 F and water boils at 2120 F.

(a) Derive the formula for converting from Fahrenheit to Celsius and back

(b) What is absolute zero on the Fahrenheit scale?

Calculate the rate of heat conduction through a layer of still air that is1mmthick, with an area of 1m2, for a temperature difference of 20C.

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.