Showing results for 
Search instead for 
Did you mean: 
New Contributor

Multistep Ka/Ksp problem

I was going over past exams and I came across problem #36 on the 2018 USNCO locals, which stumped me when I came across it. I knew acid/base equilibrium problems were one of my weak spots and I spent lot of time refining that section (I use Atkins 7th edition) but when I checked the solution for #36, it involved a really long multi-step solution where the molar solubility (MS) was assigned to a variable and you had to use several relations and equations to solve for the ratio between the final MS and the initial MS. Are there any tips for how to approach longer problems such as these, and how to recognize when to use these approaches? Are problems like these a trend or an exception in the competitions? 

Thanks for the help!


*Link to #36 Solution: 

Labels (2)
Tags (4)
0 Kudos
1 Reply
New Contributor

Re: Multistep Ka/Ksp problem

Identifying the problem type is crucial, as you did with recognizing it as an acid/base equilibrium problem, a known weak area for you. Once identified, reviewing fundamental concepts and relevant equations, as you did with Atkins 7th edition, can be beneficial. For such complex problems, breaking them down into smaller, more manageable steps is helpful. This involves identifying what is given, what needs to be found, and what intermediate steps are required to get there.

Additionally, practicing similar problems from past exams or supplementary resources can help in recognizing patterns and honing problem-solving skills. Regarding whether such lengthy problems are a trend or an exception in competitions like USNCO, it varies. While some exams may have more straightforward questions, others may include more intricate problems to challenge participants' understanding and problem-solving abilities. Therefore, being prepared for both types of questions is key to performing well in competitive exams.