Question

Some chemical reaction is being run inside a sealed gas cylinder. During the reaction, a gaseous product is formed. The pressure P exerted by the gas has been measured five times. A gauge calibrated in units of psig was used Data from the measurements are provided below Table 1. Pressure measurements of the oxygen generated by chemical reaction inside a gas cylinder Run d P (psig) 21.0 20.2 20.7 21.3 20.5 8. Estimate the Type A uncertainty in these measurements. Be sure to include the units. Estimate the Type B uncertainty associated with these measurements, Be sure to include units. Determine the uncertainty in the measurement of pressure in the cylinder. Be sure to include units. State your a. answer as average +/-uncertainty.

Answer 1

Answer:

Solution:

(A). For the evaluation of Type A uncertainty data, a single repeatability test containing mean, standard deviation and degrees of freedom

Mean

= (21.0 + 20.2 + 20.7 + 21.3 + 20.5) / 5

= 20.74 psig

Standard Deviation

= (0.26-0.54-0.04 + 0.56-0.24)2/5 = 0

Degrees of Freedom

= n-1 = 5-1

= 4

(B). For the evaluation of Type B uncertainty data, because the standard deviation is zero, therefore Type B will be uncertain.

(C). Average standard

=20.74 x 5

=103.70 psig