Wednesday, January 6, 2021

Random questions during interviews

From along-time denizen of chemistry Twitter Anthony Maiorana comes a new newsletter, the Polymerist. This is a long and interesting post about good approaches to job hunting, and I agree with all of it. I found these questions pretty amusing: 

In every technical presentation I’ve given I have had to answer questions from the audience. In crafting your presentation you should know many of the logical questions. If you are really good you can lead the audience with what questions you want them to ask and have the answer on the next slide.

Sometimes you get asked ridiculous questions that have no bearing on what you are presenting about. This might happen during the presentation or it might happen during 1-on-1 interviews with team members or non-team members. An example might be:

  • What is the density of water in lbs/gallons?
  • You talked about viscosity on your last slide. Explain to me what viscosity is from a fundamental point of view.
  • Can you give me the total synthesis of methyl methacrylate from crude oil?
I actually quite enjoy a good question from the audience, and I have had my job prospects sunk by a particularly good one (and one that I should have known!) The density of water question is kinda trivial-ish, but it's a good opportunity to answer trivia/think on one's feet/demonstrate the ability to calculate out loud (i.e. I know that it's 8 lbs per gallon, but you should be able to get there any number of different ways.) I also think it's fair to ask professor-ish questions about viscosity, but someone who asks about viscosity with the word "fundamental" is asking for math that I can't really do well (how do you calculate centipoise again?) 

Asking good questions in seminars is an art, and so is answering the questions, i.e. you need to stop, listen to the question, and engage the questioner as best as you can with your knowledge. It's not an easy skill to learn, and the only way to get better at it is to present one's work to an engaged audience (which is a non-trivial task itself...)


  1. How many barbershops are there in the US?

  2. The premise of the third question is wrong. MMA is predominantly made from the reaction of acetone and HCN followed by hydrolysis and methanolysis. While the acetone does from crude (typically as the byproduct of phenol production from propylene and benzene), the methanol and the HCN come from natural gas. The latter is made by reacting ammonia (itself from natural gas) and more methane.

    It's actually kind of fun to figure this stuff out. But who is expected to memorize it, unless they happen to be working in that particular niche of the industry?

  3. Most interesting "strange" interview question I got was during my interviews for the US Nuclear power program. I had just finished intermediate mechanics in physics about 2 months before the series of interviews.

    The interviewer asked me to set up an inclined plane problem (like in General physics). I started and he interrupted me about half-way through:

    "No, no, no. Do it with the Lagrangian."

    Still debating if that was a dick move or intentional to see if I could handle pressure. Maybe both.

  4. In one interview, I was asked to provide the mechanism for the formation of bisphenol-A from acetone + phenol, which is super trivial if you know a little organic chemistry. And this was for a PhD-level Scientist position. The interviewer told me that he had cases where other PhDs struggled with this.

    Another case is a company which did not ask any technical questions at all, only brainteasers (e.g. "A windowless room has 3 lightbulbs. You are outside the room with 3 switches, each controlling one of the lightbulbs. If you can only enter the room one time, how can you determine which switch controls which lightbulb?"). Supposedly this was to test for general intelligence and "out of the box" thinking, Google interview style.


looks like Blogger doesn't work with anonymous comments from Chrome browsers at the moment - works in Microsoft Edge, or from Chrome with a Blogger account - sorry! CJ 3/21/20