### Knowing Which Equation to Use

Posted:

**Sat Oct 12, 2019 6:19 pm**When approaching quantum problems, what is your method to determine which equation we should be using?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=18&t=47087

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Posted: **Sat Oct 12, 2019 6:19 pm**

When approaching quantum problems, what is your method to determine which equation we should be using?

Posted: **Sat Oct 12, 2019 8:22 pm**

I use Dr. Lavelle's problem solving guidelines:

1. What is the question?

2. What concepts do I know?

3. What model or equations do I know?

4. What is known? What is unknown?

5. Can I express unknown with respect to the known?

1. What is the question?

2. What concepts do I know?

3. What model or equations do I know?

4. What is known? What is unknown?

5. Can I express unknown with respect to the known?

Posted: **Sat Oct 12, 2019 8:25 pm**

I usually start by figuring out what variables I know and then finding an equation that has the unknown variable in it, filling in all the known variables that apply to that equation.

Posted: **Sat Oct 12, 2019 8:33 pm**

At the moment, I'm distinguishing them based off of electromagnetic radiation and the quantum mechanics of electrons. For example, De Brogile's equation can only be applied to electrons, NOT light.

Posted: **Sat Oct 12, 2019 11:13 pm**

I usually begin by circling the quantities and units given in the problem, and what type of unit I need to find. Then, I just find which equation allows me work between what is given and the unknown.