### Answer being a tad bit off

Posted:

**Tue Oct 08, 2019 4:04 pm**For one question I got the answer 13.8, but the answer is 13.5. Will I be docked off a lot of points for this?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=9&t=46689

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Posted: **Tue Oct 08, 2019 4:04 pm**

For one question I got the answer 13.8, but the answer is 13.5. Will I be docked off a lot of points for this?

Posted: **Tue Oct 08, 2019 4:37 pm**

I think you will be docked off a little since it is off in the 0.1 decimal place, which is far off and probably a result of rounding too early on in the problem. We need to be as precise as possible when solving chemistry problems, so only round to the correct number of sig figs when you reach the final answer.

Posted: **Tue Oct 08, 2019 5:35 pm**

I'm not sure if points will be deducted for this, but the way you can avoid this error is by storing all calculated values in your calculator until the final value is reached. If you round the values before the final step, you may obtain an error in your final calculation.

Posted: **Tue Oct 08, 2019 6:08 pm**

I am not sure about grading, but rather use unrounded values until the end to ensure you come out with the correct answer. Your answer may be a tad off because you may have been using rounded values throughout.

Posted: **Tue Oct 08, 2019 6:37 pm**

You probably have that answer due to the fact that you round every time. Don't round every time. As in grading, probably cause it is kinda significant but i don't think much tho.

Posted: **Tue Oct 08, 2019 7:54 pm**

I remember my TA saying that you should have the exact answer if a problem was done correctly so you would get a point off if it was a little off.

Posted: **Tue Oct 08, 2019 8:34 pm**

For this, make sure you check with the other parts of your equation as well. For example, the book uses 6.022 x 10^23 as Avogadro's constant, and many students may only use 6.02 x 10^23. Or, in another example, the book also uses more values for elements under the periodic table, whereas Professor Lavelle placed 4 significant figures on the molar mass of each element.

It is also better to take the full number and round off at the very end as the last step to get the most precise answer.

It is also better to take the full number and round off at the very end as the last step to get the most precise answer.

Posted: **Fri Oct 11, 2019 11:28 am**

How far off is too far off?

Posted: **Sat Oct 12, 2019 5:14 pm**

Try to avoid rounding the numbers you use for your calculation, and only round at the end of the problem. Excess rounding while solving a problem leads to significant discrepancies between your answer and the correct answer.