Molar Volume of a Gas lab: How do I determine the volume of hydrogen collected at STP and SATP, and the molar volume at STP and SATP?

Room temperature (°C) 22.0 Barometric pressure (kPa) 100.5 Water vapor pressure at 22 °C (kPa) 2.60 Mass of Mg ribbon (g) 0.0500 Volume of hydrogen gas (mL) 48.3 Observations of reaction • when the Mg came into contact with the HCl bubbles of gas (H2) were produced • the H2 produced displaced the water in the graduated cylinder

oh here: 2HCl(g) + Mg(s) -> H2(g) + MgCl2(aq) nMg = 0.0020571899 mol nH2 = 0.0020571899 mol Wet H2 pressure = 100.5 kPa Dry H2 pressure = 97.9 kPa --- Vstp = 22.4 L/mol, and Vsatp = 24.8 L/mol Vstp:0 degrees Celsius and 101.325 kPa while Vsatp: 25 degrees Celsius and 100 kPa. 100.5 kPa x 760 mm Hg/101.325 kP = 753.8119911 mmHg So to determine the volume of hydrogen gas collected at STP: V2 = (753.8119911 mmHg)(48.3 mL)(273 K) / (295 K)(760 mmHg) = 44.33403003 mL Molar volume at STP: mol/L = 44.33403003 mL / 0.0020571899 mol = 21550.77176 mL/mol = 21.55077176 L/mol To determine volume of hydrogen gas collected at SATP: V2 = (100.5 kPa)(48.3 mL)(298 K) / (295K)(100kPa) = 49.03514237 mL Molar volume at SATP: mol/L = 49.03514237 mL / 0.0020571899 mol = 23835.98246 mL/mol = 23.8359824 L/mol Are my answers correct? :$

You have the work out with: Volume of H2 (STP) : V' = ( 48.3 ml * 97 .9 * 273 ) / 100.5 * 295 = 43.54 mL Mole of H2 = .0434 ml / .0021 = 21.17 mol

so wait only the volume of H2 (ST) is wrong?

The key is you need to use corrected Pressure 97 .9 kPa, because we want the dry H2 gas!

ohh didn't I use it?

ohhh.. i don't use the wet one?

V2 = (753.8 mmHg)(48.3 mL)(273 K) / (295 K)(760 mmHg) = 44.33 mL I doesn't look like you use the dry one !!!

so basically I replace the 100.5 kPa from both of the calculations STP and SATP to 97.9 kPa?

lol, thank you!

ohh it's 20993.23937.. o.O

The 20.73 mol is the correct one.

wait I am so confused now D:

this part: Mole of H2 = .0435 L / .0021 = 20.73 mol

ohhh i see it. Never mind, thanks again!

Volume of H2 (STP) : V' = ( 48.3 ml * 97 .9 * 273 ) / 101.3 * 295 = 43.197 mL Molar Volume of H2 = .043197 ml / .0021 = 20.99 mol

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