UTC: Friday, July 21st, 2017

Which R do I use?

Which R do I use? It’s a common question for chemistry students, and when it comes to the AP chemistry exam there is a choice of values for the ‘Universal’ Gas Constant. Currently appearing on an AP formula sheet near you, one can find the following; a. R = 8.314 J mol-1 K-1 b. R […]

Which R do I use?

NOTE: There is now an updated (April 2016) version of this post to reflect the new curriculum. Which R do I use? It’s a common question for chemistry students, and when it comes to the AP chemistry exam there is a choice of values for the Universal Gas Constant. Currently appearing on an AP formula […]

Root mean square speed and k versus R

A student asked me today (thanks, Austin) why there are two different expressions given on the AP exam for calculating the root mean square speed of a gas, and how this can be explained in terms of the use of k, R, m and M. Here’s the answer that I gave. You will find two […]