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Whole Numbers, One Sig Fig

Posted: Sun Oct 08, 2017 2:37 pm
by Shannee Mak 3F
Say you get a number like 52 as an answer, but the smallest amount of sig figs in the problem is 1 sig fig. How would you round? Would you put the answer as 50?

Re: Whole Numbers, One Sig Fig  [ENDORSED]

Posted: Sun Oct 08, 2017 2:44 pm
by Bansi Amin 1D
The number 50 still has two sig figs, so instead you'd have to write the number 50 in scientific notation without the decimal point. So it would be written as 5 x 10^1.

Re: Whole Numbers, One Sig Fig

Posted: Sun Oct 08, 2017 2:48 pm
by Bansi Amin 1D
Hold up, sorry, the number 50 only has two sig figs if a decimal is in place, so you'd be fine with rounding down to 50. All though I'm not sure if you'd encounter a situation where there would only be one sig fig required to be in the answer.

Re: Whole Numbers, One Sig Fig

Posted: Sun Oct 08, 2017 3:18 pm
by Chem_Mod
Yes, you round 52 to 50 if you only need one sig fig. Generally, rounding in Chemistry is how you round normally except for numbers ending in 5 (round to nearest even number in this case).

To review general sig fig rules:
-All NON-ZERO numbers ARE significant
-leading 0s are NEVER significant (i.e., 0.0075 and .025 is 2 sig figs.)
-trapped 0s (0s in the middle) are ALWAYS significant (i.e., 504, 0.0206 are both 3 sig figs.)
-tricky part is in the trailing 0s (at the end of a number): if there is any decimal ANYWHERE in the number, then the trailing 0s ARE significant. For example, 500., 0.0200, and .250 all have 3 sig figs because a decimal exists somewhere in the number. Note: 500 is 1 sig fig while 500. is 3 sig figs.