REPORT: EXPERIMENT 11 (Mw0fCO) Name IvAN AINAIARIZ-Date- Data 1. Mass of the fla

Question

REPORT: EXPERIMENT 11 (Mw0fCO) Name IvAN AINAIARIZ-Date- Data 1. Mass of the flask and dry air 2. Density of dry air 3. Mass of the dry air 4. Trial 1 Trial 2 2.1 25.14g 6 7 90 Mass of the empty flask 5, Mass of the flask and CO2 6. Mass of the CO y -ue 31 , 42.31,g 7. Volume of the flask (CO,)210 L 7. Volume of the flask (CO2) 8. Barometric Pressure 9. Room Temperature CALCULATIONS: SHOW WORK. 1. Choose Method A or Method B. Method A: (1) Using the Combined Gas Law, correct the volume of the CO: (flask) to STP. (2) Based upon your volume at STP how many moles of CO2 were present? (Hint: 22.4 liters is the volume of 1 mole at STP.) Method B: Using the Ideal Gas Equation, PV-nRT, determine the moles of CO2 gas that were present. 2. Using your moles of CO2 (from Method A or Method B), determine the molecular weight (g/mole of CO2 3. Compare the experimental molecular weight to the accepted value and determine the percent error EXERCISES: SHOW WORK.

Explanation / Answer

Part 1: Method B used for calculation of number of moles

PV = nRT

Where

P = Pressure = 29.26 mmHg converted to 3901.01241 Pa (SI unit) [1mmHg = 133.3223 Pa]

V = Volume = 270 L (SI unit)

n = number of moles = to be calculated

R = constant = 8.314 J·K1·mol1

T= temperature = 19.800C converted to 292.9500 K (SI unit) [10C= 274.1500K]

Solution:

PV = nRT

n        = P x V/ R x T

                = 3901.01241 x 270 / 8.314 x 292.9500

                = 1053273.35/ 2435.58

                = 432.45

Thus, the number of moles of CO2 present is 432.45

Part 2: Calculating the molecular weight of CO2

Since n (number of moles) = m (mass)/M (molar mass = Mol. wt)

M      = m/n

                = 6.790 / 432.45

                = 0.0157 g/mole

Part 3: calculation of % error

Experimental Mol Wt. of CO2 = 0.0157 g/mole

Accepted Mol Wt. of CO2 = 44.0095 g/mole

% error            = ([Approx. value – exact value] / exact value) x 100

                                = ([0.0157 - 44.0095] / 44.0095) x 100

                                = (- 44.079 / 44.0095) x 100

Since the absolute value of a number is the value of the positive value of the number, whether it's positive or negative so ignore the negative value

                                = 1.001 x 100

                                = 100.1 %

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