Sapling 5/6 #9

[Jaclyn Schwartz 1I]

Hi! I need a little help with the following.

Consider the following reaction at 298 K.

C(graphite)+2H2(g)⟶CH4(g) ΔH∘=−74.6 kJ

Calculate the following quantities. Refer to the standard entropy values as needed.

I understand how to calculate the entropy of the system but I am confused with how to find the surrounding and univ. And help would be appreciated on how to start!

[Sahiti Annadata 3D]

The change in entropy of the system is given by

ΔS∘sys=∑S∘(products)−∑S∘(reactants)

where S∘ is the standard entropy.

The change in entropy of the surroundings is given by

ΔSsurr=−ΔHsysT

The change in entropy of the universe is the sum of the change in entropy of the system and the change in entropy of the surroundings.

ΔSuniv=ΔSsys+ΔSsurr

[Alexis Sanft 1E]

To find the surroundings you use the equation Δ Ssurr = −Δ Hsys / T. To find the universe you use the equation ΔSuniv = ΔSsys + ΔSsurr. I hope this helps.

[Nathan Tong 3G]

For this question, the first step would be to covert your ΔH^o from kJ to J by multiplying by 1000, to match with the units of J/K. Then insert this enthalpy of the system into the equation ΔS_surr = -ΔH_sys / T . Finally, take the sum of ΔS_sys and ΔS_surr to caculate the ΔS_univ.

[Jaclyn Schwartz 1I]

The change in entropy of the system is given by

ΔS∘sys=∑S∘(products)−∑S∘(reactants)

where S∘ is the standard entropy.

The change in entropy of the surroundings is given by

ΔSsurr=−ΔHsysT

The change in entropy of the universe is the sum of the change in entropy of the system and the change in entropy of the surroundings.

ΔSuniv=ΔSsys+ΔSsurr

This was super helpful! Thank you!