/*! 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} Q10E Question: A freezer has a coeffi... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Question: A freezer has a coefficient of performance of \(2.40\). The freezer is to convert \(1.80\;kg\) of water at \(25.0^\circ C\) to \(1.80\;kg\) of ice at \( - 5.0^\circ C\) in one hour. (a) What amount of heat must be removed from the water at \(25.0^\circ C\) to convert it to ice at \( - 5.0^\circ C\)? (b) How much electrical energy is consumed by the freezer during this hour? (c) How much wasted heat is delivered to the room in which the freezer sits?

Short Answer

Expert verified

The total heatremoved from the water at \(25^\circ {\rm{C}}\) to convert it to ice at \( - 5^\circ {\rm{C}}\) is \(8.081 \times {10^5}\;{\rm{J}}\).

Step by step solution

01

Write the given data from the question.

Coefficient of performance,\(K = 2.40\)

Mass of water, \(m = 180\;{\rm{kg}}\)

Initial temperature of water,\({T_0} = 25^\circ {\rm{C}}\)

Final temperature of ice,\({T_1} = - 5^\circ {\rm{C}}\)

02

Determine the formula to calculate the amount of heat must be removed from the water at \(25.0^\circ C\) to convert it to ice at \( - 5.0^\circ C\).

The expression to calculate the amount of heat when water is converted from \(25^\circ {\rm{C}}\) to \(0^\circ {\rm{C}}\) is given as follows.

\({Q_1} = m{c_w}\Delta T\) …… (i)

Here,\({c_w}\)is the specific heat of water, and\(\Delta T\)is the change in temperature.

The expression to calculate the amount of heat when water is converted from \(0^\circ {\rm{C}}\) of water to \(0^\circ {\rm{C}}\) of ice is given as follows.

\({Q_2} = m{L_f}\) …… (ii)

Here,\({L_f}\)is the fusion of water.

The expression to calculate the amount of heat when water is converted from \(0^\circ {\rm{C}}\) of ice to \( - 5^\circ {\rm{C}}\) of ice is given as follows.

\({Q_3} = m{c_{ice}}\Delta T\) …… (iii)

Here,\({c_{ice}}\)is the specific heat of ice.

The expression to calculate the total heatremoved from the water at \(25^\circ {\rm{C}}\) to convert it to ice at \( - 5^\circ {\rm{C}}\) is given as follows.

\({Q_C} = {Q_1} + {Q_2} + {Q_3}\) …… (iv)

03

Calculate the amount of heat must be removed from the water at \(25.0^\circ C\) to convert it to ice at \( - 5.0^\circ C\).

The specific heat of the ice,\({c_{ice}} = 2100\;{{\rm{J}} \mathord{\left/ {\vphantom {{\rm{J}} {{\rm{kg}} \cdot {\rm{K}}}}} \right.\{{\rm{kg}} \cdot {\rm{K}}}}\)

The fusion of water,\({L_f} = 334 \times {10^3}\;{{\rm{J}} \mathord{\left/ {\vphantom {{\rm{J}} {{\rm{kg}}}}} \right.\{{\rm{kg}}}}\)

Calculate the amount of heat when water is converted from \(25^\circ {\rm{C}}\) to \(0^\circ {\rm{C}}\).

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 91Ó°ÊÓ!

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

A jet fighter pilot wishes to accelerate from rest at a constant acceleration of to reach Mach 3 (three times the speed of sound) as quickly as possible. Experimental tests reveal that he will black out if this acceleration lasts for more than5.0s. Use331m/sfor the speed of sound. (a) Will the period of acceleration last long enough to cause him to black out? (b) What is the greatest speed he can reach with an acceleration ofbefore he blacks out?

In Wagner’s opera Das Rheingold,the goddess Freia is ransomed for a pile of gold just tall enough and wide enough to hide her from sight. Estimate the monetary value of this pile. The density of gold is 19.3 g/cm3, and take its value to be about $10 per gram.

The human circulatory system is closed—that is, the blood pumped out of the left ventricle of the heart into the arteries is constrained to a series of continuous, branching vessels as it passes through the capillaries and then into the veins as it returns to the heart. The blood in each of the heart’s four chambers comes briefly to rest before it is ejected by contraction of the heart muscle.

If the contraction of the left ventricle lasts 250ms and the speed of blood flow in the aorta (the large artery leaving the heart) is 0.80 m/s at the end of the contraction, what is the average acceleration of a red blood cell as it leaves the heart? (a) 310 m/s2; (b) 31 m/s2; (c) 3.2 m/s2; (d) 0.32 m/s2.

How many years older will you be 1.00 gigasecond from now? (Assume a 365-day year.)

A car is stopped at a traffic light. It then travels along a straight road such that its distance from the light is given byxt=bt2-ct3, whereb=2.40m/s2andc=0.120m/s3. (a) Calculate the average velocity of the car for the time interval t = 0 to t = 10.0 s. (b) Calculate the instantaneous velocity of the car at t = 0, t = 5.0 s, and t = 10.0 s. (c) How long after starting from rest is the car again at rest?

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.