(Unless otherwise noted, 2 pts. for each blank) Molarity of HCI (M) (Ipt. each):
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Question
(Unless otherwise noted, 2 pts. for each blank) Molarity of HCI (M) (Ipt. each): Volume of HCl (mL): Mass of Mg (gram): *Volume of gas before placing in Data, Trial 1 .00M Data, Trial 2 3.OOM 2o.com 30.08 mL Equalization Chamber (mL) (I pt.) (This value NOT used in calculatioes below) Volume of gas after placing in Equalization Chamber (mL): Barometric Pressure (mm Hg): Temperature (°C): Write the balanced overall equation for the reaction of magnesium and HCl to form hydrogen 732.3 mm tg 132.5mmHa 23. 2°C 23.2°C gas and the magnesium salt (2 pts): Mole of Mg reacted Mole of H2 formed (based on the stoichiometric equation for the reaction) Vapor Pressure of water from curve in mmtg: Pressure or 12 from Dalton's Law in mmHg: Pressure of H2 in atm Volume of H2 in liter (Using volume measared in Equalization Chamber) Temperature in Kelvin Calculation of R (6 pts. each) Percent error Average R- 63Explanation / Answer
Balanced equation
Mg(s) + 2HCl (aq) = MgCl2(s) + H2(g)
Trial 1
Moles of Mg reacted = mass/molecular weight
= 0.035g/24.305g/mol
= 0.00144 mol
Moles of HCl = molarity x volume = 3 mol/L x 0.020 L
= 0.060 mol
From the stoichiometry of the reaction
1 mol Mg required = 2 mol HCl
0.00144 mol Mg required = 2*0.00144 = 0.00288 mol HCl
But we have more moles of HCl than required
Limiting reactant = Mg
Moles of H2 formed = moles of Mg consumed = 0.00144 mol
Vapor pressure of water at 23.2 °C = 21.329 mmHg
Pressure of H2 = Barometric pressure - Vapor pressure of water
= 732.5 - 21.329 = 711.171 mmHg
Pressure of H2 in atm = 711.171 mmHg x 1atm/760mmHg
= 0.93575 atm
Volume of H2 in L = 36.35 mL x 1L/1000 mL = 0.03635 L
Temperature = 23.2 + 273.15 = 296.35 K
From the ideal gas equation
R = PV/nT
= 0.93575 atm x 0.03635 L / 0.00144 mol x 296.35 K
= 0.07971 L-atm/mol-K
% error = (true value - experimental value) *100 / true value
= (0.08206 - 0.07971) *100/0.08206
= 2.86%
Similarly from trial 2
Moles of Mg reacted = mass/molecular weight
= 0.037g/24.305g/mol
= 0.00152 mol
Moles of HCl = molarity x volume = 3 mol/L x 0.020 L
= 0.060 mol
From the stoichiometry of the reaction
1 mol Mg required = 2 mol HCl
0.00152 mol Mg required = 2*0.00152 = 0.00304 mol HCl
But we have more moles of HCl than required
Limiting reactant = Mg
Moles of H2 formed = moles of Mg consumed = 0.00152 mol
Vapor pressure of water at 23.2 °C = 21.329 mmHg
Pressure of H2 = Barometric pressure - Vapor pressure of water
= 732.5 - 21.329 = 711.171 mmHg
Pressure of H2 in atm = 711.171 mmHg x 1atm/760mmHg
= 0.93575 atm
Volume of H2 in L = 36.63 mL x 1L/1000 mL = 0.03663 L
Temperature = 23.2 + 273.15 = 296.35 K
From the ideal gas equation
R = PV/nT
= 0.93575 atm x 0.03663 L / 0.00152 mol x 296.35 K
= 0.07609 L-atm/mol-K
% error = (true value - experimental value) *100 / true value
= (0.08206 - 0.07609) *100/0.08206
= 7.27%
Average R = (0.07609 + 0.07971) / 2
= 0.0779
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