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Can someone please help me with this exercise? I\'m desperate. I have a test on

ID: 1060066 • Letter: C

Question

Can someone please help me with this exercise? I'm desperate. I have a test on monday.

The following data have been obtained for the adsorption of H2 on the
surface of 1.00 g of copper at 0°C. The volume of H2 below is the volume that
the gas would occupy at STP (0°C and 1 atm).
p/atm 0.050 0.100 0.150 0.200 0.250
V/cm3 23.8 13.3 8.70 6.80 5.71
Determine the volume of H2 necessary to form a monolayer and estimate the
surface area of the copper sample. The density of liquid hydrogen is 0.708 g cm3.

The solution's manual changed the volume but I don't know how the calculation were made:

p/atm 0.050 0.100 0.150 0.200 0.250
V/cm3 1.22 1.33 1.31 1.36 1.40

Can someone explain to me how to calculate the volume from 23.8 to 1.22?

Explanation / Answer

From your question:

"Can someone explain to me how to calculate the volume from 23.8 to 1.22?"

The most logical relationship between the volumes is pressure

the initial volumes are based on P = 1 atm

so we must correct the volume for the actual pressure

so

Vnew = Pnew/Pold * Vold

so

for

p/atm 0.050 0.100 0.150 0.200 0.250
V/cm3 23.8 13.3 8.70 6.80 5.71

use

Vnew = (0.05)/1 * 23.8 = 1.19 --> 1.20

Vnew = (0.10)/1 * 13.3 = 1.33 --> 1.33

Vnew = (0.150 )/1 * 8.70 = 1.305 --> 1.31

Vnew = (0.200)/1 * 6.80 = 1.36 --> 1.36

Vnew = (0.250)/1 * 5.71= 1.4275 --> 1.42