15.2/R1.4 Calculate the standard entropy change for a reaction [HL IB Chemistry]

15.2 Calculate the standard entropy change for a reaction using standard entropy values. Same old same old -- this is just products minus reactants. Don't forget to account for the coefficients. The chemicals themselves have ENTROPY values ,S, but the equation has the CHANGE IN ENTROPY value, delta S.

[chrisbuswell]

Hi Richard,
Thank you so much for providing the world with these videos. As an IB Chemistry teacher myself, I wish I was given school time to work on curriculum resources like this!
You might want to provide a correction to this video. The entropy values for methanol used are incorrect and and even with the values you have used the algebra does not equate. Thanks again

[willow]

I have no idea what's going no! VERY STRESS TEACHER!!!

[rashed]

The data booklet says that the entropy for methanol is +127 not +240

[jennicatblink]

Hi, but what if the s values have no given number and only the equation like your sample, N2+3H2-> 2NH3.

Sorry can't still understand how did they get the values of each elements

[raybohall]

can you post a video on this problem?  

Find the increase in entropy of 3.40 kg of liquid oxygen that starts at its boiling temperature, boils, and warms to 24.0°C at constant pressure.

[JayK-wbfm]

Just in case anyone else is confused as to why he used N2 in the MaryHaber-Calculation; Unlike enthalpies of formation, standard molar entropies of elements are not 0.

[cisco]

A bit too straight forward with the answer. What did you subtract or divide to get 130.5 jk. You just went straight to the answer and I’m getting lost.

[olivierlynn]

thank you soooo much that really helped a lot!! 

[seemak]

I am doubtful about the unit u used for entropy change. It must be just J/K.

[SyrianSoaper]

youre british so youre instantly not boring for us americans ;)

[cisco]

Are you missing a negative because I keep getting -130.5 J not +130.5 J

[mohamedmusabeh]

how do you get those numbers in the beginning for n2, h2 and nh3

[hellodolly]

why you didn't put zero of the element?

[alonator]

I don't understand the math for the last equation :/