Significant digits in calculation

AI Thread Summary
The discussion focuses on determining the appropriate number of significant figures (sf) for calculations involving multiplication and division. For the conversion of 20 kiloseconds to hours, the calculation yields 5.5555 hours, which should be rounded to 6 hours based on the 1 significant figure in 20. However, the book suggests 5.6 hours, indicating a preference for 2 significant figures. Similarly, the conversion to minutes results in 333.333 minutes, which can be rounded to either 333 or 330 minutes, depending on the chosen significant figures. Both approaches are valid, highlighting the importance of clearly stating the significant figures used in calculations.
php006
Messages
2
Reaction score
0
Hello everyone:
I am trying to figure out the how many significant figures (sf), should I keep in the final
answer for multiplication and division
1. How many hours and minutes are 20 kiloseconds?



2.



3. for hours: 20*10e3 / 3600 = 5.5555 hrs
20 has only 1 significant figure (trailing zero doesn't count), hence the answer should have 1 sf, that means I should round answer to the single digits. my final answer is 6 hr. My book give 5.6 hr as the answer.
please let me know my approach is correct

for minutes 20*10e3 / 60 = 333.333 minutes
keep only 1 sf in the result,that leads my answer to 333 minutes
my book give 330 and the final answer
 
Physics news on Phys.org
Your book appears to be choosing 2 significant digits. However you could just as well choose 3 sf and still be correct. I would state what I'm using for sf, in my solution. To 3 sf, hours would be 5.56hr. If you see the answer in your book as 5.6hr, you should realize, both answers are correct.
 
Thread 'Confusion regarding a chemical kinetics problem'
TL;DR Summary: cannot find out error in solution proposed. [![question with rate laws][1]][1] Now the rate law for the reaction (i.e reaction rate) can be written as: $$ R= k[N_2O_5] $$ my main question is, WHAT is this reaction equal to? what I mean here is, whether $$k[N_2O_5]= -d[N_2O_5]/dt$$ or is it $$k[N_2O_5]= -1/2 \frac{d}{dt} [N_2O_5] $$ ? The latter seems to be more apt, as the reaction rate must be -1/2 (disappearance rate of N2O5), which adheres to the stoichiometry of the...
Back
Top