Calculate the change in entropy of the universe

In summary, the conversation discusses calculating the change in entropy of the universe as a result of a process involving a copper block and a lake. The correct formula for finding the change in entropy is provided, along with the given temperature values and the resulting answer of 6.3 JK-1. The discrepancy between the given answer and the calculated answer is attributed to a possible mistake in not carrying the units through the calculation. It is also noted that heat capacity, rather than specific heat capacity, should be used in the calculation given the mass provided in the question.
  • #1
Harmony
203
0

Homework Statement



Calculate the change in entropy of the universe as a result of the following process:

A copper block of mass 0.4 kg and heat capacity 150 JK-1 at 1000C is placed in a lake at 100C.


2. The attempt at a solution

change in entropy (copper) = mc ln (T2 / T1)

change in entropy (lake) = mc ( T1 - T2 ) / T2

where T1 = 373 K, T2 = 283 K.

The answer given is 6.3 JK-1. which is differ from the answer I got. May I know if i have done any careless mistake?
 
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  • #2
Carry your units through the calculation and you'll see.
 
  • #3
Thanks a lot Mapes! I never realize that it is heat capacity instead of specific heat capcity (as they give us mass in the question). :)
 

FAQ: Calculate the change in entropy of the universe

What is entropy?

Entropy is a thermodynamic quantity that measures the disorder or randomness of a system. It is often referred to as the "arrow of time" as it tends to increase over time in closed systems.

What is the change in entropy of the universe?

The change in entropy of the universe is a measure of the overall increase or decrease in disorder or randomness in the entire universe. It takes into account all the changes in entropy that occur in different systems within the universe.

How is the change in entropy of the universe calculated?

The change in entropy of the universe can be calculated using the formula ΔS = ΔSsystem + ΔSsurr, where ΔSsystem is the change in entropy of the system and ΔSsurr is the change in entropy of the surroundings.

Why is the change in entropy of the universe important?

The change in entropy of the universe is important because it helps us understand the direction of natural processes. In accordance with the second law of thermodynamics, the change in entropy of the universe will always be positive, meaning that the overall disorder of the universe will always increase.

What factors affect the change in entropy of the universe?

The change in entropy of the universe is affected by various factors such as temperature, pressure, and the nature of the system and its surroundings. Changes in energy and matter also play a role in determining the change in entropy of the universe.

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