How many moles of ethanol were poured in the bottle yesterday? Write the balanced chemical reaction for the reaction of ethanol and oxygen to make water and carbon dioxide. Assuming that all of the ethanol reacts, what is the theoretical yield of water (in mL, remembering that water’s density is 1 g/mL) from this reaction? Now we will pour out the liquid left in the bottle. The volume is: _____________ Assuming it is water, calculate the percent yield of this reaction. Based on the flame test of the liquid left in the bottle, was it water? Explain Woofer Quiz Answers and How To C2H5OH (2 x 12.01) + 6 (1.01) + 16.0 = 46.08 g/mol (28.7mL) (.80 g/mL) = 22.96 g 22.96g/46.08g/mol = .498 mol .50 mol C2H5OH + 3 O2 2 CO2 + 3 H2O 3 moles of water from each mole of ethanol so 3(.5mol) = 1.5 mol water (1.5 mol)(18.02 g/mol) = 27.03 g water = 27 mL of water This will vary depending on how much liquid is left in the woofer. Let’s say it’s 24ml of liquid: (24/27) x 100% = 89% yield No, it wasn’t water because it was flammable. It must have been ethanol. There must have been more ethanol in the bottle than oxygen, so the fire went out before all of the ethanol was able to be burned up. (I often do this reaction after introducing stoichiometry but before talking about limiting reagents)
How many moles of ethanol were poured in the bottle yesterday? Write the balanced chemical reaction for the reaction of ethanol and oxygen to make water and carbon dioxide. Assuming that all of the ethanol reacts, what is the theoretical yield of water (in mL, remembering that water’s density is 1 g/mL) from this reaction? Now we will pour out the liquid left in the bottle. The volume is: _____________ Assuming it is water, calculate the percent yield of this reaction. Based on the flame test of the liquid left in the bottle, was it water? Explain Woofer Quiz Answers and How To C2H5OH (2 x 12.01) + 6 (1.01) + 16.0 = 46.08 g/mol (28.7mL) (.80 g/mL) = 22.96 g 22.96g/46.08g/mol = .498 mol .50 mol C2H5OH + 3 O2 2 CO2 + 3 H2O 3 moles of water from each mole of ethanol so 3(.5mol) = 1.5 mol water (1.5 mol)(18.02 g/mol) = 27.03 g water = 27 mL of water This will vary depending on how much liquid is left in the woofer. Let’s say it’s 24ml of liquid: (24/27) x 100% = 89% yield No, it wasn’t water because it was flammable. It must have been ethanol. There must have been more ethanol in the bottle than oxygen, so the fire went out before all of the ethanol was able to be burned up. (I often do this reaction after introducing stoichiometry but before talking about limiting reagents)
VSEPR_stoich_thermo_session_handouts.docx