Should Significant Figures be affected by constants?

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Nicholas Carpo 1L
Posts: 36
Joined: Fri Sep 28, 2018 12:19 am

Should Significant Figures be affected by constants?

Postby Nicholas Carpo 1L » Wed Oct 10, 2018 11:51 pm

I am a confused by whether significant figures in solutions should be limited by the number of significant figures in constants.

For example:

If my given frequency is 5.11111 x 10^14 Hz (6 Significant Figures) and the constant for speed of light I use is 3.00 x 10^8 m/s (3 Significant Figures), should my final answer be 5.86957 x 10^-7 m (6 Significant Figures like the given) or 5.87 x 10^-7 m (3 Significant Figures like the constant).

tl;dr: Should the number of significant figures we use in constants affect the number of significant figures in the final answer?

Mahir_Hasan2C
Posts: 60
Joined: Fri Sep 28, 2018 12:25 am

Re: Should Significant Figures be affected by constants?

Postby Mahir_Hasan2C » Thu Oct 11, 2018 12:05 am

It shouldn't affect the constants since they are typically rounded off. Typically, significant figures are for the shortest amount of digits.

anthony_trieu2L
Posts: 60
Joined: Fri Sep 28, 2018 12:29 am

Re: Should Significant Figures be affected by constants?

Postby anthony_trieu2L » Thu Oct 11, 2018 12:11 am

The significant figures in your final answer should not be affected by the number of sig figs in your constants. Simply put, apply the sig figs rules based on the number of sig figs of the variable given to you in the problem. In your case, your final answer should be 5.86957 x 10^-7 m since 6 sig figs were assigned to the variable.

305115396
Posts: 30
Joined: Fri Sep 28, 2018 12:16 am

Re: Should Significant Figures be affected by constants?

Postby 305115396 » Thu Oct 11, 2018 11:54 am

Sig figs are not affected by constants. The amount of sig figs that you use in your answer should be the amount of the value given in the problem.

Kevin ODonnell 2B
Posts: 62
Joined: Fri Sep 28, 2018 12:24 am

Re: Should Significant Figures be affected by constants?

Postby Kevin ODonnell 2B » Thu Oct 11, 2018 12:30 pm

I don't believe a constant would effect the number of sig figs you should round to in your answer, but rather it should be a given number such as 5.0g since that is a number that the person asking the question can change based off how many significant figures they are looking for in the answer. There are a few helpful sig fig explanations on the Chem website. https://lavelle.chem.ucla.edu/class-websites/chem14a/

Peichung Chou 1A
Posts: 30
Joined: Fri Sep 28, 2018 12:21 am

Re: Should Significant Figures be affected by constants?

Postby Peichung Chou 1A » Fri Oct 12, 2018 9:17 am

Significant figures are not affected by constants that are input.

jguiman4H
Posts: 31
Joined: Fri Sep 28, 2018 12:29 am

Re: Should Significant Figures be affected by constants?

Postby jguiman4H » Fri Oct 12, 2018 9:55 am

Significant figures are not affected by constants similar to how measured values like 1m = 100 cm are not used as sig figs. You would just need to look at what numbers you are given in the actual question itself as constants do not affect the sig figs.

Kyither Min 2K
Posts: 60
Joined: Wed Oct 03, 2018 12:15 am

Re: Should Significant Figures be affected by constants?

Postby Kyither Min 2K » Fri Oct 12, 2018 3:21 pm

Constants do not affect significant figures since significant figures are a sense of how precise something is. Constants are known to be very precise and would have no affect on the final calculation for significant figures since it's already known to be precise.

Yiting_Gong_4L
Posts: 69
Joined: Fri Sep 28, 2018 12:25 am

Re: Should Significant Figures be affected by constants?

Postby Yiting_Gong_4L » Fri Oct 12, 2018 10:23 pm

Constants do not have an affect on the amount of sig figs to use.

305008749
Posts: 31
Joined: Fri Sep 28, 2018 12:27 am

Re: Should Significant Figures be affected by constants?

Postby 305008749 » Fri Oct 12, 2018 10:36 pm

when you guys say sig figs aren't affected by constants, does that mean we will still get the right answer if we use them or to not use it? In other words we should just ignore the constants and go based off the variables given to us?

204765696
Posts: 23
Joined: Wed May 16, 2018 3:00 am

Re: Should Significant Figures be affected by constants?

Postby 204765696 » Sat Oct 13, 2018 1:07 pm

Significant figures are not affected by constants. The important rule is to have the same amount of significant figures in your answer and in the value given in the original problem.


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