### Equations

Posted:

**Fri Oct 09, 2015 3:39 pm**What are some of your ways of remembering which formula goes with a specific question? I seem to be confused a lot about what I have to use in a specific problem.

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=29&t=6014

Page **1** of **1**

Posted: **Fri Oct 09, 2015 3:39 pm**

What are some of your ways of remembering which formula goes with a specific question? I seem to be confused a lot about what I have to use in a specific problem.

Posted: **Fri Oct 09, 2015 3:57 pm**

What works for me is I usually see what is given, and what the question is asking for. From there, if the formula used to find what they're looking for doesn't correspond to what was given, I look at what can be found with what was given (ex. given wavelength, I can find frequency).

Posted: **Fri Oct 09, 2015 8:58 pm**

As soon as you go into an exam, or even when doing a homework problem, make sure you write down all the equations you can remember at the top of your page. This way you'll be able to concentrate more on doing the actual problem and not worry about having to concentrate on remembering the equations. In regards to knowing which equation to use, as you go through the problem, break it down into small sections and note down all the information it's saying in short, and write down what they want you to find with little question marks next to them. This will help you recognize the variables and constants and will hopefully help you identify which equation you have to use. For example, in a question about the energy of a photon, the could give you the frequency, so note down v = 10Hz, and tell you to find E(photon), so write down E = ?. Hopefully you'll recognize that the equation you need is E = hv. Hope this helped!

Posted: **Tue Oct 13, 2015 9:44 pm**

What seems to work best for me is writing down all the given info. Other than the given, write down what is needed to be found. Use all this info and find which equation best fits all of the info you have written down. Like Jacqueline said, if none of the equations seem to fit try to see if you can find the missing variable from another equation with your given info. Hope this helps!