<p>Hi,</p>
<p>I'm currently an AP Chemistry TA in my school and I was wondering about a few things in the new curriculum. </p>
<p>In previous years, the use of the Henderson Hasselbalch equation was allowed on the AP Exam (pH = pKa + log (A-/HA). However, this year, it has been taken off as a formula that is given.</p>
<p>So I was wondering, if my students can derive this equation on the spot during the AP Exam, will credit still be given?</p>
<p>Hey Clausius,</p>
<p>I’m taking AP Chemistry this year, and I have a copy of the equations chart we get to use (Can be found here: <a href=“http://media.collegeboard.com/digitalServices/pdf/ap/IN120085263_ChemistryCED_Effective_Fall_2013_lkd.pdf[/url]”>http://media.collegeboard.com/digitalServices/pdf/ap/IN120085263_ChemistryCED_Effective_Fall_2013_lkd.pdf</a> (Page 160)). Students are given the Henderson-Hasselbalch equation, and even if it wasn’t given on the chart, it’s not about how you get the answer right, it’s that you do get it right - you just have to show work. Also, students can still use a RICE table fork buffers and get the same answer, the equation is just faster, but if your students can derive the equation on their own too, that’s perfectly fine, the free-response stresses getting the answer correct, then readers are instructed to try and find points to give to the test taker if they get the wrong answer by locating where in the calculations they messed up (that’s why you should write your work out on the AP test).</p>
<p>I’ll be the AP Chemistry TA for my school next year after this year so I’ve stressed about this too. Don’t worry!</p>
<p>-Bryce</p>