Using units in calculations [ENDORSED]

[Anna De Schutter - 1A]

Hi!

I've noticed in the solutions manual that units are used for every value when doing calculations. For example if they want to calculate the number of moles of C knowing that the mass of C is 67.49g (problem F15) they write:
(67.49g)/(12.01g/mol)=5.619mol
I was just wondering would it be okay to write: (67.49)/(12.01)=5.619mol and not include the units of 67.49 and 12.01 or should we always include the units when doing calculations?

Thank you so much!
Anna De Schutter, section 1A

[Andrew Evans - 1G]

I would always use units in your calculations just so you can check yourself and see that your units are properly canceling out to give you the desired resulting unit.

Also in dimensional analysis, where you start with one value and use value relationships (stoichiometry, molarity, molar masses, ect.), by using units in your calculation, you can visualize for yourself and the grader how you are relating each value to each other.

Hope this helps :)
–Andrew Evans
Section 1G

[Jennifer Tuell 1B]

In addition to units I would also add what element or molecule the value is connected to, especially when dealing with moles.

[Bianca Nguyen 1B]

Hi!

I believe that as long as your final answer includes the correct units, then doing the calculations without units should be fine, BUT I definitely agree with Andrew on this one as including units in your calculations really aids in your understanding as well as the grader’s in how you got from Point A to B and so on. Also, if your final answer is wrong, you could score some partial credit through using the correct units in your calculations as your process leading up to the final answer will be understood more clearly!

[Nina_A_Section1E]

To make it clear where you're getting your numbers from, it could be helpful to include units, but as long as it's clear without them what you're doing, and you get the right answer and give it with the correct units, I bet it'll be okay!