Carbonate Buffer Systems Lab Partner Sectio TA Name c. How does this value compa
ID: 513891 • Letter: C
Question
Carbonate Buffer Systems Lab Partner Sectio TA Name c. How does this value compare to the actual mass of Namco, in the beaker? What is the percent error? Show your calculations for full credit calculated actual mass actual mass X 100 Error 9.10 usna) C. Soos x IOO The calculated mass is slignty greater than the actual mass. d. The standard deviation and error are measures that indicate the presence of error in an experi- ment. Discuss both values and list possible sources of error in your execution of this lab.Explanation / Answer
Standard deviation
While measuring any physical quantities we may get data values which are not close to the expected result then we can say in this measurement there is standard deviation. It's basically the quantity which take care of the variations or dispersion. During measuring any quantity the data values should be as much closer as possible to mean.
Mean of NaOH=(0.1016+0.1025+0.1019+0.1041+0.1017)/5=0.10236=0.1024
So standard deviation of NaOH=root{[(0.0008)^2+(-0.0001)^2+(0.0005)^2+(0.0017)^2+(0.0007)^2]/(5-1)}=root{64*10^-8+1*10^-8+25*10^-8+279*10^-8+49*10^-8}/(5-1)]=0.0010
Mean of HCl=(0.1957+0.1930+0.1985+0.1916+0.1935)/5=0.19446=0.1945
So standard deviation of HCl=root{[(0.0012)^2+(0.0015)^2+(0.0045)^2+(0.0029)^2+(0.0010)^2]/(5-1)}=root[{144*10^-8+225*10^-8+2025*10^-8+841*10^-8+10^-6}/(5-1)]=0.0027
% error
Mass of Na2CO3 titrated=0.4579 g
Calculated mass =0.5003 which is slightly more than the experimental(ie from titration) value.
So % error=[(0.5003-0.4579)/0.4579]*100 %=4.24 %
Cause of these error
During titration 1 to 2 drops might be extra added which can lead to error.
If glasswares are not washed properly with chromic acid, many impurity is there which can lead to error.
Glasswares should be properly dried before titration is started as amount of water in glasswares after washing can dilute the acid or bases which may lead to error.