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Using the data from the first experiment, how can the mass percent of carbon in the unknown compound be determined?
A. (1.55 x 12.011 / 22.41 x 1.00) x 100%
B. (1.55 x 22.41 x 12.011/ 1.00) x 100%
C. (22.41 x 12.011 / 1.55 x 1.00) x 100%
D. (22.41 x 1.00 / 1.55 x 12.011) x 100%
Relevant information from the passage:
1.0g liquid hydrocarbon sample
1.55 L of CO2 gas from oxidized sample
22.41 L Molar volume of ideal gas
TBR eliminates all answer choices but A because they are all over 100%. My questions comes in their explanation of figuring out the problem if you didn’t recognize that 3 answer choices were over 100%. They state that the mass of carbon in CO2 will equal the mass of carbon in the unknown. They find this by taking moles of CO2 (1.55/22.41) multiplied by the mass of carbon (12.011) and then divide that by the mass of the sample (1.00).
When calculating the moles of CO2 the units are L / (L/moles) giving you moles. In this case it would be 1.55/22.41 moles of CO2. Are they able to multiply the moles of CO2 (1.55/22.41) by the mass of carbon (12.011) because there is 1 mole of C in CO2? If instead we were asked to find the mass percent of oxygen in the unknown would you take the moles of CO2 (1.55/22.41) x 2 then multiply by the mass of O2?
A. (1.55 x 12.011 / 22.41 x 1.00) x 100%
B. (1.55 x 22.41 x 12.011/ 1.00) x 100%
C. (22.41 x 12.011 / 1.55 x 1.00) x 100%
D. (22.41 x 1.00 / 1.55 x 12.011) x 100%
Relevant information from the passage:
1.0g liquid hydrocarbon sample
1.55 L of CO2 gas from oxidized sample
22.41 L Molar volume of ideal gas
TBR eliminates all answer choices but A because they are all over 100%. My questions comes in their explanation of figuring out the problem if you didn’t recognize that 3 answer choices were over 100%. They state that the mass of carbon in CO2 will equal the mass of carbon in the unknown. They find this by taking moles of CO2 (1.55/22.41) multiplied by the mass of carbon (12.011) and then divide that by the mass of the sample (1.00).
When calculating the moles of CO2 the units are L / (L/moles) giving you moles. In this case it would be 1.55/22.41 moles of CO2. Are they able to multiply the moles of CO2 (1.55/22.41) by the mass of carbon (12.011) because there is 1 mole of C in CO2? If instead we were asked to find the mass percent of oxygen in the unknown would you take the moles of CO2 (1.55/22.41) x 2 then multiply by the mass of O2?