## Constants

$\ln K = -\frac{\Delta H^{\circ}}{RT} + \frac{\Delta S^{\circ}}{R}$

Caroline Cox 1H
Posts: 18
Joined: Fri Sep 29, 2017 7:03 am

### Constants

Can someone explain to me why we can assume that deltaH and deltaS are constant when using the Van't Hoff equation to calculate K at different temperatures?

Anh Nguyen 2A
Posts: 36
Joined: Fri Sep 29, 2017 7:05 am
Been upvoted: 1 time

### Re: Constants

Because the values of enthalpy and entropy at different temperature are different but the difference between the final value and initial value is the same no matter what the temperature so we can assume that deltaH and deltaS are constant at different temperature.

Ilan Shavolian 1K
Posts: 58
Joined: Fri Sep 29, 2017 7:03 am

### Re: Constants

im pretty sure since they are state functions, they can be considered constant

nathansalce 3e
Posts: 52
Joined: Thu Jul 27, 2017 3:01 am

### Re: Constants

Technically, we do not assume that deltaH and deltaS are constants... but rather we assume the difference in deltaH and deltaS between the two equations (for the two temperatures) is the same.Thus, we say that the rate at which H and S change is not the same, but the difference between the two values is the same at both temperatures, allowing us to compare other values at the two temperatures.

Abby Ellstrom 1I
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

### Re: Constants

The change in enthalpy and entropy does not change between different temperatures in this equation so they can be treated as constant.