Use the sig fig rule. Lowest number of digits.
I would put 5.2 atm
I am trying to find pressure.
R=.0821
T=1273 K
V=2
n=.0997
When I put .0997 in the PV=nRT equation I get 5.2 atm, and when I put in .09 I get 4.7 atm.
Which answer should I put? Which is more accurate?
5 answers
When I use the lowest number of digits (i think your talking about .09) I get 4.7atm.
I mean I multiplied everything out and then I figured out how many sig figs there should be. I would use the exact numbers that the problem gives you.
Ok. Thank you.
I would use 0.0997 for n. Then I would use 0.08206 for R. That gives me 5.207 and round that to the number of s.f. you have. If the 2 for V is 2 then you have only 1 s.f. so the answer would be 5 atm. If it is 2.0 or 2.00, then I would round to 5.2 or 5.21 respectively. My philosophy is to use all the digits you know for everything and let the calculator carry all those extra places, then round at the end. To round ahead of time makes too many rounding errors. By the way, you wouldn't round 0.0997 to 0.09 anyway. You would round it to 0.1 if you were doing it that way. YOu can see that using 0.09 makes a HUGE difference in the answer.
1 answer