Sig Fig Mistakes
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Sig Fig Mistakes
For significant figures, does it matter how many sig figs you choose to use? Will anyone care if you choose to use four sig figs rather than three as long as you're being consistent?

 Posts: 110
 Joined: Thu Jul 11, 2019 12:16 am
Re: Sig Fig Mistakes
For sig figs, it depends on the question. Typically, the sig figs of the given amount in the problem is the number of sig figs you use for your final answer. However, that's not always true.
So you shouldn't be using 3 sig figs for every single answer just for consistency; you have to look at the question and choose the sig figs accordingly.
Hope this helped!
So you shouldn't be using 3 sig figs for every single answer just for consistency; you have to look at the question and choose the sig figs accordingly.
Hope this helped!

 Posts: 50
 Joined: Thu Jul 11, 2019 12:16 am
Re: Sig Fig Mistakes
For multiplication/division, the result should have the same number of sig figs as the value that has the least number of sig figs which is being multiplied/divided.
For example, if you are multiplying a value with two sig figs and a value with three sig figs, then the result should have two sig figs as that is what the value with the least number of sig figs has.
As for addition/subtraction, the result should be rounded off to the least precise decimal point in the subtraction/addition equation.
For example, 140.22  110.1 would yield 30.12. But with the application of sig fig rules, the answer should be rounded off to 30.1 since the tenths decimal point is the least precise point shown in a comparison between 140.22 and 110.1.
For example, if you are multiplying a value with two sig figs and a value with three sig figs, then the result should have two sig figs as that is what the value with the least number of sig figs has.
As for addition/subtraction, the result should be rounded off to the least precise decimal point in the subtraction/addition equation.
For example, 140.22  110.1 would yield 30.12. But with the application of sig fig rules, the answer should be rounded off to 30.1 since the tenths decimal point is the least precise point shown in a comparison between 140.22 and 110.1.

 Posts: 50
 Joined: Thu Jul 25, 2019 12:16 am
Re: Sig Fig Mistakes
I agree with the post above. I remember from high school chem there were certain sig figs rules. For example, when multiplying or dividing, you answer with the least number of sig figs in the problem. For addition and subtraction, the answer can not contain more decimal places than the least precise value.

 Posts: 50
 Joined: Thu Jul 25, 2019 12:17 am
Re: Sig Fig Mistakes
Typically, you find the number with the smallest number of sig figs given in the problem and use that as a guidance as to how many sig figs you should have in your final answer!

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 Joined: Sat Aug 24, 2019 12:17 am

 Posts: 58
 Joined: Sat Aug 17, 2019 12:15 am
Re: Sig Fig Mistakes
Can someone please explain the sig fig rules regarding addition and subtraction as well as multiplication and division? I forget which one is about having the same amount of decimal places and which needs the same amount of sig figs. Thank you!

 Posts: 105
 Joined: Fri Aug 09, 2019 12:16 am
Re: Sig Fig Mistakes
Should we round off the numbers as we calculate or leave them as is until the final answer?

 Posts: 50
 Joined: Sat Aug 17, 2019 12:18 am
Re: Sig Fig Mistakes
The general idea for sig figs is that you are trying to be precise because your calculation is only as accurate as your least accurate measurement. For example for the hypothetical problem find moles of F in 25.2kg of UF6, it is important to round your answer to three sig figs at the end. The reasoning for this is because the only numeric value they give us explicitly (yes you can deduce the molar mass), is 25.2 kg, we have to use this as our benchmark for sig figs as there are three numeric values present.

 Posts: 105
 Joined: Fri Aug 30, 2019 12:18 am
Re: Sig Fig Mistakes
I was taught to not round as you calculate, as that would interfere with the accuracy of your final answer. Then, you can round and use the sig figs.Letty Liu 1K wrote:Should we round off the numbers as we calculate or leave them as is until the final answer?

 Posts: 103
 Joined: Sat Aug 17, 2019 12:18 am
Re: Sig Fig Mistakes
The number of sig figs you use should depend on the number with the least number of sigfigs given in the question. For example, if the problem gives you an amount like 3.2 grams and 4.56 grams, your answer should have 2 sigfigs since 3.2 grams only has 2 sigfigs.
Re: Sig Fig Mistakes
I know this was already asked but if we don't use accurate sig figs will we lose points during exams?

 Posts: 104
 Joined: Thu Jul 25, 2019 12:18 am
Re: Sig Fig Mistakes
When dealing with multiplication or division problems, the number of sig figs in your answer should equal the smallest number of sig figs in the given values. When dealing with addition and subtraction problems, the number of sig figs in your answer should equal the smallest number of decimal places in the given values.

 Posts: 96
 Joined: Wed Nov 21, 2018 12:19 am
Re: Sig Fig Mistakes
I think you round the answer's sig fig to the smallest number at the calculation

 Posts: 115
 Joined: Sat Sep 07, 2019 12:16 am
Re: Sig Fig Mistakes
In addition to this statement, during calculations it is best not to round as accuracy may be lost in the final answer. Therefore, it is best to round to the least amount of significant figures given to you in the exercise at the end for the answer (as stated below).
Madeline Phan 4H wrote:The number of sig figs you use should depend on the number with the least number of sigfigs given in the question. For example, if the problem gives you an amount like 3.2 grams and 4.56 grams, your answer should have 2 sigfigs since 3.2 grams only has 2 sigfigs.

 Posts: 52
 Joined: Thu Jul 25, 2019 12:16 am
Re: Sig Fig Mistakes
One important thing to note is that when determining the number of sig figs to use in your final answer, you don't consider the amount of sig figs in constants such as Avogadro's number.

 Posts: 81
 Joined: Wed Dec 05, 2018 12:18 am
Re: Sig Fig Mistakes
The sig fig rules depend on if a certain amount of them are given in the problem, if they are then your final answer should contain the same amount of sig figs, if they are not then depending on multiplying/division you use the sig figs of the smallest number for your answer and for addition and subtraction, you use the one with the least decimal places in your answer.

 Posts: 98
 Joined: Fri Aug 30, 2019 12:15 am
Re: Sig Fig Mistakes
Typically the amount of significant figures used for your answer is determined by the amount gaven to you in the question. Usually it follows these rules
any nonzero digits are always significant.
Any zeros between two significant digits are still significant.
any nonzero digits are always significant.
Any zeros between two significant digits are still significant.
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