The volume of the pressure vessel is 4.4 liters. The number of moles of H2 gas f

Question

The volume of the pressure vessel is 4.4 liters. The number of moles of H2 gas formed can be determined for the unknown samples.

Enter the corrected gas pressures (after subtracting the water vapor pressure) for unknowns 1 and 2. For Unknowns 1 & 2, Make sure you subtract 20 from the pressure in torr measured in the lab to obtain the corrected pressure.

Unknown 1 - ? torr

Unknown 2 - ? torr

For the next two unknowns, use the ideal gas equation, and the volume obtained above to calculate the number of moles of H2 gas produced during each unknown run. Assume the gas temperature at the end of each run is 22 deg c

Unknown 1 - ? moles H2

Unknown 2 - moles H2

Use the formula PV=nRT to solve for n (number of moles). You know the volume, or "V" (4.4 L), you know the value of R (0.0821 L x atm/mol x K). Make sure you convert the temperature to Kelvin and the pressure to atm before plugging into this formula.

Explanation / Answer

Here first we need to measure pressure(in torr) experimetalty in the lab. Now to get the correct pressurre we need to subract 20 torr from the experimetal pressure. Hence

For unknown-1, P1 = (P1expm - 20) torr

For unknown-2, P2 = (P2expm - 20) torr

Now we need to convert the pressure in torr to pressure in atm.

Hence P1(in atm) = (P1expm - 20) torr x (0.001316 atm / 1 torr) = 0.001316x (P1expm - 20) atm

P2 (in atm) = (P2expm - 20) torr x (0.001316 atm / 1 torr) = 0.001316x (P2expm - 20) atm

Now the pressure for the unknown-1 and 2 are ready.

T = 22 DegC = 295 K

R = 0.0821 L x atm/mol x K

V = 4.4 L

Now we can calculate the number of moles for each unknown sample thrugh ideal gas equation.

PV = nRT

=> n = PV / RT

For unknown-1: n1 = (0.001316x (P1expm - 20) atm x 4.4 L) / (0.0821 Lx atm/mol-1xK-1 x 295K)

For unknown-2: n2 = (0.001316x (P2expm - 20) atm x 4.4 L) / (0.0821 Lx atm/mol-1xK-1 x 295K)

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