• :00Days
  • :00Hours
  • :00Mins
  • 00Seconds
A new era for learning is coming soonSign up for free
Log In Start studying!

Select your language

Suggested languages for you:
Answers without the blur. Sign up and see all textbooks for free! Illustration

Q11P

Expert-verified
Fundamentals Of Physics
Found in: Page 604

Answers without the blur.

Just sign up for free and you're in.

Illustration

Short Answer

In an experiment, 200 g of aluminum (with a specific heat of 900J/kg.K) at 100°C is mixed with 50.0g of water at 20.0°C, with the mixture thermally isolated.(a)What is the equilibrium temperature?(b)What is the entropy changes of the aluminum, (c)What is the entropy changes of the water, and (d)What is the entropy changes of the aluminum – water system?

a) The equilibrium temperature of aluminum-water system is 330K.

b) Change in entropy of the aluminum is -22.1J/K.

c) Change in entropy of the water is 24.9 J/K

d) Change in entropy of the aluminum-water system is 2.8 J/K

See the step by step solution

Step by Step Solution

Step 1: The given data

a) Mass of the water, mw=50.0 g or 50×10-3 kg

b) Mass of the aluminum, mal=200g or 200×10-3kg

c) Temperature of aluminum, Tal=100°C or 373 K

d) Temperature of water, Tw=20.0°C or 293K

e) Specific heat of aluminum, cal=900 J/kg.K

f) Specific heat of water, cal=4190J/kg.K

Step 2: Understanding the concept of equilibrium and entropy change

Entropy change is a phenomenon that quantifies how disorder or randomness has changed in a thermodynamic system. We can write the condition of equilibrium for heat energy absorbed and transferred by the two blocks, and by writing it in terms of specific heat and temperature; we can find the value of equilibrium temperature of the two-block system. Then, by using the formula for change in entropy, we can find the change in entropy of the aluminum, water, and aluminum-water system.

Formulae:

The heat transferred by the body, Q=mcT …(i)

The entropy change of the gas, S=mclnTfTi …(ii)

Step 3: (a) Calculation of the equilibrium temperature of aluminum-water system

At equilibrium, the total heat of the system is zero. So,Qw+Qal=0

Using equation (i) and the given values, we can get that

role="math" localid="1661323263437" mwcwTw+malcalTal=0

Let the equilibrium temperature be Tf Then, the above equation becomes

mwcw(Tf-Tw)+malcal(Tf-Tal=050×10-3kg4190J/kg.KTf-293K+200×10-3kg900J/kg.KTf-373K=0 209.5Tf-61383.5+180Tf-67140=128523.5 389.5Tf =128523.5 Tf=329.97K 330K

Hence, the value of the equilibrium temperature is 330K

Step 4: (b) Calculation of the entropy change of aluminum

Substituting the given values in equation (ii), we get the entropy change of aluminum as given:

S=200×10-3kg900J/kg.KIn329.97K373K =-22.06J/K =-22.1J/K

Hence, the value of the entropy change is -22.1J/K

Step 5: (c) Calculation of the entropy change of water

Substituting the given values in equation (ii), we get the entropy change of water as given:

S=50×10-3kg4190J/kgKIn329.97K293 K =24.89J/K 24.9J/K

Hence, the value of the entropy change is 24.9 J/K

Step 6: (d) Calculation of the entropy change of aluminum-water system

Change in entropy of the system = Change in entropy of water + Change in entropy of aluminum.

So, the total entropy change of the aluminum-water system is given as follows:

S=Sw+Sal =-22.06J/K+24.89J/K 2.8J/K

Hence, the value of the entropy change of the system is 2.8J/K

Recommended explanations on Physics Textbooks

94% of StudySmarter users get better grades.

Sign up for free
94% of StudySmarter users get better grades.