[Gerard]

i was experimenting the absorption of CO2 in water using Packed Bed Column with rascvhig rings as packing, to dtermine CO2 in air i use HEMPL Gas analyzer while to determine CO2 in water i use titration with a base,my problem is that when i calculated for the change in x and y there was a negative results why is it so?
here are me data.
X2(Sumptank X)
1.4663x10^-5
2.1994x10^-5
2.1994x10^-5
2.2518x10^-5
2.3042x10^-5

x1(downcoming x)
1.8329x10^-5
2.1994x10^-5
2.2518x10^-5
1.9900x10^-5
2.4613x10^-5

to find the change in x i have to: x1-x2 (out minus in)
but you can find that there are negative values,,,why?

in terms of y
my inital CO2 in air is 0.0663

while my CO2 in the experiment was 2L/min CO2 in 30 L/min air
Y2
0.01
0.015
0.0525
0.0625
0.07
0.0675
0.0625
0.0625
0.0625
0.0625

to determine the change in y i have to Y1-Y2 (again in minus out)
but there are still negative values here, how can i correct these to get a positive graph?