Question

Name RT PV R30.08206 cm CHMISTRY IA, EXPERIMENT Experimental Determination of R Pre la questions: Gas volume measurement To 23°0 P.762 mming 193 mL of o, wis collected over water on a day when the atmospheric wessure was 762 mm . The temperature of the water was 23. 0°C. How many ains or orygon were collected? (Hint recall: Dalton's law and the vapor pressure of Postal Potom Ges collection water at 23.0°C) 2. Hydrogen gas was collected over water as shown in the diagram below. Calculate the pressure of the Hydrogen gas collected. Water temperature was 23.0°C and the atmospheric pressure was 741.0 mmHg. (Hint the density of Mercury is 13.6 g/mL) 220. mm.

Answer 1

1)

volume of O2 = 193 mL = 0.193 L

pressure = 762 mmHg

vapor pressure of water at 23 oC = 21.1 mmHg

pressure = 762 - 21.1 = 740.9 mmHg

              = 0.975 atm

temperature = 23 oC = 296 K

P V = n R T

0.975 x 0.193 = n x 0.0821 x 296

n = 0.00774 mol

moles of O2 = 0.00774

mass of O2 = 0.00774 x 32 = 0.248 g

mass of oxygen = 0.248 g