entropy positive value

[Funmi Baruwa]

In lecture 13, Dr Lavelle said something about entropy always being a positive value. Does anyone understand why this is?

[Lorraine Jiang 2C]

I think he said entropy is always positive for a continuous(spontaneous) reaction?

Hope it helps!

[Margaret Wang 2D]

The second law of thermodynamics states that the entropy of the overall universe is always increasing (positive), but it is always possible for a certain smaller section of the universe to decrease in entropy.

[Funmi Baruwa]

oh okay thank you

[jia207]

I believe entropy will always be positive for a continuous/spontaneous reaction

[Anastasia Yulo 1C]

Entropy is always positive when looking at the entropy of the universe, as entropy and disorder is always increasing when looking at the system perspective of the universe.

[Kaley Qin 1F]

He was saying that entropy is always increasing for the universe, so the change in entropy of the universe is always positive

[Saumya Tawakley 1E]

Entropy will be positive for a spontaneous reaction, and the change in entropy of the universe is positive as well because the universe tends toward disorder (which translates to higher entropy).

[Wil Chai 3D]

I don't remember specifically what he was talking about, but something to note: he could have been referring to the standard entropy values of common substances (found in tables), which are always positive.

[Dominic Benna 2E]

It is always positive for a spontaneous reaction.

[Karina Grover 1A]

As the second law of thermodynamics states, the entropy of the universe is always increasing and, thus, positive. In addition, a positive entropy (for a system) indicates a spontaneous reaction. I hope this helps!

[Anh Trinh 1J]

Entropy is expected to increase when a given amount of matter spreads into a greater volume or is mixed with another substance. A spontaneous process has a natural tendency to occur, so when entropy is positive, it is a spontaneous process.

[Britney Tran IJ]

entropy is positive for a spontaneous reaction

[Nina Fukui 2J]

The entropy of the universe is always positive. I think that's what you're talking about

[Eliana Witham 2H]

The entropy of the universe is always increasing, but individual reactions can have a decrease in entropy. For example, a phase change going from liquid to solid is a decrease in entropy because there is more order in a solid than liquid.

[Giselle Granda 3F]

According to the second law of thermodynamics, entropy of the universe must always be positive in order for a spontaneous process to occur. Also, entropy is only positive at high temperatures, because high temperatures increase the disorder in the system, whereas at low temperatures, entropy is more negative since it is more ordered. Therefore, entropy is not always positive!

[Olivia Smith 2E]

Entropy in the universe will always be increasing according to the second law of thermodynamics. However, within a system it could be decreasing but the surrounding entropy change will be larger than the decreasing entropy of the system

[Mari Williams 1K]

Change in entropy of the universe must always be positive, but by identifying smaller systems you can find negative entropy changes :)

[rhettfarmer-3H]

I think he was referring to spontaneous reactions. hence, the second law says that the universe always increases disorder. However, there are some small changes in the universe that do restore order. So S can be negative.

[EmilyGillen_1A]

I wanted to chime in that at first I was also confused about why entropy is always increasing because there was a problem in which the entropy decreases (instead of increasing). It boils down to the fact that the order of the entropy is always increasing because entropy = randomness, and the randomness of the universe is always increasing. But when you look at a closed or individual reaction, it is possible that the entropy of that reaction is decreasing (the S of the System would decrease, but the S of the Surrounding would increase). On a large scale, the surroundings, aka the universe, always increase but the entropy of a system itself can decrease.

[Mehreen 3I]

Entropy is positive for a spontaneous reaction.

[Isabella Cortes 2H]

entropy of the universe will always be a positive value even if the entropy of a system decreases. Entropy will also be positive for spontaneous reactions.

[Rachel Kwan 1B]

For some reason I thought that entropy could be negative even if the reaction was spontaneous. Can delta H be more negative than the positive value of T(deltaS) and create a spontaneous reaction?

[John_Tran_3J]

It is definitely not always positive, because there is always disorder in the world.

[LovepreetSran_3H]

He was saying that the entropy of the universe is always positive.

[Melis Kasaba 2B]

I believe Lavelle said that because the total entropy of the universe is always increasing. Additionally, in an irreversible reaction, entropy always increases. However, there can be a decrease in entropy for a system that is not closed.

[Astha Patel 2J]

I think he was referring to the second law, which states that an isolated system's entropy will always increase over time. A system can have a negative change in entropy, but overall somewhere in the universe, the entropy will increase.

[Keshav Patel 14B 2B]

Entropy values are always positive values because spontaneous values need to be constant.

[Griffin G]

Entropy will always have a net increase, no matter what happens. The disorder of the universe is constantly increasing.

[Lauren Mungo 1K]

The entropy of the universe is always increasing and therefore is always positive

[Gian Boco 2G]

I think for the universe or for most spontaneous reactions.