In this experiment we evaluated R the gas law constant PVnRT

In this experiment we evaluated R, the gas law constant. PV=nRT

Most top-loading balances used in this experiment measure a mass only to the nearest mg(+/- 0.001 g). This significantly affects the calculation of R in the experiment. Explain why this is so. How might the procedure be modified to compensate for this systematic error?

Solution

we have

mole = mass/ mol. wt

so difference in mole = -+ 0.001/M

where M is mol wt.

thus

R= PV/nT

since mole is not measured correctly it will affect R

as dR/R= dn/n

if other things are constant

so it affects R significantly

the measurement should be repared a no. of times and take the mean mass to compensate for this error.