Data Sheet Unknown Number Sample 1 Sample 2 Volume of H gas (mL) Temperature of
ID: 1052030 • Letter: D
Question
Data Sheet Unknown Number Sample 1 Sample 2 Volume of H gas (mL) Temperature of water ( Height of water column (mm) vapor pressure of water at above temperature (mmHg) 22-3 22.0 C 213m 22.0°c (v . Barometrne pressure ( CALCULATIONS (Show calculations) Pressure of the column of water (mmHg) Pressure of dry hydrogen (mmHg) Moles of Hydrogen Mass of Magnesium ribbon (g) Average mass of magnesium ribbon (gs) Vapor Pressure of Water at Various Temperatures: Temperature () | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 Pressure (mmHg) 14.s 15.5 16.5 17.5 18.7 19.8 21.1 224 23.8 252 26.7 283 30.0 31.8 |19 | 20 23-25 26-28 ·29 |30 21-2 [ Temperature (C-17Explanation / Answer
From the given set of data
sample 1
Pressure column of water = 282 - 19.8 = 262.2 mmHg
Pressure (H2) = (29.86 x 2.54 - 19.8)/760 = 0.074 atm
moles of H2 = PV/RT = 0.074 x 0.0242/0.08205 x 295 = 7.4 x 10^-5 mol
mass of Mg = 7.4 x 10^-5 x 2 x 24.305 = 1.8 mg
sample 2
Pressure column of water = 293 - 19.8 = 273.2 mmHg
Pressure (H2) = (29.86 x 2.54 - 19.8)/760 = 0.074 atm
moles of H2 = PV/RT = 0.074 x 0.0242/0.08205 x 295 = 7.4 x 10^-5 mol
mass of Mg = 7.4 x 10^-5 x 2 x 24.305 = 1.8 mg
Avg mass of Mg = 1.8 mg
1. If the water vapor pressure was unaccounted for, the moles of H2 would be higher and so the moles of Mg and that would give a higher mass of Mg be obtained.
2. If strips had a coating of MgO, less metal wold react to form H2. Moles of H2 would be low and so mass of Mg calculated would be low as well.
3. If alloy of Al-Mg was used instead, the mass thus calculated would be higher as greater amount of H2 gas would be generated in this case.
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