Week 2 Sapling #1

[lwon Dis2I]

How do you know if a concentration change is small compared to the given initial condition?

[Keerthana Sundar 1K]

How do you know if a concentration change is small compared to the given initial condition?

In what context are you referring to a concentration change? Would you be able to point out which part of the question you're specifically referring to? If you're referring to an equilibrium reaction, if the difference between the initial condition and the equilibrium concentration is low (the percent ionization is low), then I would assume that's a good definition for a small concentration change. Perhaps less than 5%?

Hopefully that helps! Let me know if you were referring to something else!

[Valerie Doan 3I]

A concentration change is small compared to its initial concentration if the change is less than 5% of the initial. But, generally the rule of thumb is when K<10^-4 we can approximate the change as close to zero. We really only do the 5% calculation if K is on the cusp of 10^-3 or 10^-4, and we are not really sure if the change is actually that small. Hope this helps!