### Sig Figs on Tests

Posted:

**Thu Oct 10, 2019 7:19 pm**How many significant figures should we calculate with / round to on tests?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=9&t=46881

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Posted: **Thu Oct 10, 2019 7:19 pm**

How many significant figures should we calculate with / round to on tests?

Posted: **Thu Oct 10, 2019 7:21 pm**

You should be basing the number of sig figs in your answer on what information the problem gives you. You should be using the least number of sig figs that are in the problem. For example, the question may say, "uses 650. mL for 30.00g of NaCl." You should use 650. (3 sig figs) as an indication for your answer.

Posted: **Thu Oct 10, 2019 7:46 pm**

Here are the rules for sig figs:

1. Non zero digits are significant.

2. Zeros in between other digits are significant.

3. Leading zeros are NOT significant.

4. Trailing decimal zeros are significant.

5. When adding/subtracting, use the fewest number of decimal places.

6. When multiplying/dividing, use the fewest number of sig figs.

1. Non zero digits are significant.

2. Zeros in between other digits are significant.

3. Leading zeros are NOT significant.

4. Trailing decimal zeros are significant.

5. When adding/subtracting, use the fewest number of decimal places.

6. When multiplying/dividing, use the fewest number of sig figs.

Posted: **Thu Oct 10, 2019 8:01 pm**

as a general rule, if they give you a bunch of given numbers you should use the value with the least number of significant figures to write your answer.

Posted: **Mon Oct 21, 2019 11:28 am**

To figure out how many significant figures you should use, look for the number in the problem with the least amount of significant figures.

Posted: **Mon Oct 21, 2019 11:49 am**

To decide how many sig figs you need to use on the test, look at the problem and see which number has the lowest amount of sig figs. Your answer will have the same as that. Furthermore, some TA's are lenient when grading. Ask them what they think.

Posted: **Mon Oct 21, 2019 12:02 pm**

When determining sig figs, you have to take a look at the problem and look for which number has the least amount of sig figs and use that amount of sig figs in your answer. I know my TA is pretty lenient about sig figs though.

Posted: **Sun Oct 27, 2019 11:47 pm**

Your answer should have the same amount of sig figs as the lowest sig fig number given in the problem!

Posted: **Fri Nov 01, 2019 10:47 am**

Always use the lowest number of sig figs stated in the problem! I know that most TAs are lenient on sig figs, but they may grade harsher for the midterm.

Posted: **Fri Nov 01, 2019 11:05 am**

You should round according to the least number of sig figs in a questions. Remember to keep as many sig fits as possible while doing to problem and round at the final step.

Posted: **Sun Nov 10, 2019 11:56 pm**

Just look at the numbers they give you on the test and base it off of that

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Posted: **Sun Nov 17, 2019 1:55 pm**

When using dimensional analysis throughout the problem, make sure to use ALL the numbers given in the periodic table and constant/equation sheet. When you get a final answer after keeping ALL numbers throughout, you will round to the least amount of significant figures given in the actual problem.

Posted: **Sun Nov 17, 2019 4:57 pm**

The number of significant figures you put your answer in is based on the question, so the least amount of significant figures in the question is used.

Posted: **Tue Nov 26, 2019 2:37 pm**

You should calculate/round to the fewest number of sig figs given in a problem.

Posted: **Tue Nov 26, 2019 3:39 pm**

You should usually give the answer in terms of the number of the value given to you in the problem with the least number of sig figs.

Posted: **Sat Nov 30, 2019 6:41 pm**

Now, when multiplying two or more numbers, it is important to have the final answer in the form of the smallest sig figs. Values found on the periodic table do not count in this sig fig process. Values found through calculation or in the problem count as sig figs. If the sig figs are not clear, it is best to leave the answer in three sig figs.

Posted: **Sun Dec 01, 2019 11:15 am**

Also remember that it was mentioned in each step of a calculation, you may round to the proper amount of sig figs as your final answer. Rounding error from this will not be an issue from what I understand.

Posted: **Sun Dec 01, 2019 12:27 pm**

Generally your answer uses the least amount of precision given. So if one number has three sig figs and the other has 4 the answer would use 3.

Posted: **Thu Dec 05, 2019 11:16 pm**

Your answer should have the same number of sig figs as the number with the least amount of significant figures given in the problem.

Posted: **Thu Dec 05, 2019 11:42 pm**

The problem usually contains an initial number and is usually the standard for how many sig figs need to be in the answer. As a rule of thumb the answer should have the lowest number of sig figs as given in the problem.

Posted: **Fri Dec 06, 2019 12:16 am**

The answer should have the same number of sig figs as the number (of sig figs) in the question.

Posted: **Sat Dec 07, 2019 12:47 pm**

Usually your answer should match the lowest amount of significant figures given in the question.

Posted: **Sun Dec 08, 2019 9:27 pm**

3 significant values is the usual statistical value to complete calculations.

Posted: **Sun Dec 08, 2019 9:29 pm**

for pH, the number of digits after the decimal point equates to the total number of sig figs for the concentration

Posted: **Sun Dec 08, 2019 9:29 pm**

You should match it with the sig figs the problem gives you, or the lowest amount.