How many significant figures? [ENDORSED]
Moderators: Chem_Mod, Chem_Admin
-
- Posts: 34
- Joined: Fri Apr 06, 2018 11:03 am
How many significant figures?
On one of the UA's practice tests (Lyndon's), question 7a asked "An excited hydrogen atom undergoes an electronic transition from n=3 to n=1. Calculate the frequency of the photon emitted." Since the question only contains numbers with 1 significant figure, should we answer with only one?
-
- Posts: 15
- Joined: Fri Apr 06, 2018 11:02 am
Re: How many significant figures?
Since these numbers reference atomic energy level and cant be any non-integer I don't think they effect sig figs. That being said I would give the exact value.
-
- Posts: 62
- Joined: Fri Apr 06, 2018 11:04 am
Re: How many significant figures?
Just remember to use the rules of sig figs when either multiplying/dividing or adding/subtracting. With multi./division you keep the same number of digits as the smallest number of sig figs in your problem and for addition/subtraction, you keep the sig fig until the digit of the least accuracy.
-
- Posts: 31
- Joined: Fri Apr 06, 2018 11:04 am
Re: How many significant figures?
I'd keep 3-4 sig figs just to be safe. Having only one sig fig for a value that wont be a whole number (or a single digit for that manner) doesn't make too much sense.
-
- Posts: 23858
- Joined: Thu Aug 04, 2011 1:53 pm
- Has upvoted: 1253 times
Re: How many significant figures?
Isabel Jabara 1C wrote:On one of the UA's practice tests (Lyndon's), question 7a asked "An excited hydrogen atom undergoes an electronic transition from n=3 to n=1. Calculate the frequency of the photon emitted." Since the question only contains numbers with 1 significant figure, should we answer with only one?
Use the number of sig figs given by the constants that you used. For example, planck's constant will be given with a certain number of sig figs.
-
- Posts: 23858
- Joined: Thu Aug 04, 2011 1:53 pm
- Has upvoted: 1253 times
Re: How many significant figures? [ENDORSED]
n=1 and n=3 are values whose sig figs we DO NOT take into account because we know the EXACT value of these.
Return to “Bohr Frequency Condition, H-Atom , Atomic Spectroscopy”
Who is online
Users browsing this forum: No registered users and 7 guests