Ethanol Fermentation Question - straightforward?
(52.166 g C12H22O11) / (342.2979 g C12H22O11/mol) x (4 mol C2H6O / 1 mol C12H22O11) x (46.06867 g C2H6O/mol) = 28.083 g ethanol if all the sucrose reacted Supposing the 12% figure is a mass percent and the density of the solution containing all the reactants and products at the point the yeast dies to be about the same as water (1 g/mL): (250 mL) x (1 g/mL) x (0.12) = 30 g of ethanol when the yeast dies So it seems pretty much a wash (considering the rough estimate for the density) whether the sucrose runs out first or whether the yeast dies first, so report the theoretical yield of ethanol from the sucrose (28 g) since that's the more accurate of the two calculations. From the instructions, I don't see any reason to convert the amount of ethanol generated from grams to mL, but if you think that's necessary divide 28 g by the density of ethanol, 0.789 g/cm3.
Chemistry/Math Question?
You didn't really ask a question, but I assume you are asking how much of that 120g ethanol solution you would need to have 90 g 4-methyl-2-pentanone. You have a 120 g solution, and 22.9% of it is 4-methyl-2-pentanone. 120 * 0.229 = 27.48 g 4-methyl-2-pentanone by mass in solution. 90 g 4-methyl-2-pentanone (120 g ethanol / 27.48 g 4-methyl-2-pentanone) = 393 g ethanol solution. To have 90 g 4-methyl-2-pentanone, you need around 393 g ethanol solution. If all you have is 120 g, then you can't get there.
I need help with this question?
To get the percent yield, you first have to figure out the theoretical yield. You need to figure out how many moles of ethanol were used. Since it takes two moles of ethanol to make one mole of diethyl ether, the theoretical yield of diethyl ether is 1/2 x (moles of ethanol). This question was set up to make the math easy, since the molecular weight of ethanol is about 46.0 g/mol. The molecular weight of diethyl ether is 74.1. 46.0 g of ethanol x (1 mol/46.0 g) = 1 mole of ethanol. The theoretical yield of diethyl ether then is 1/2 x 1 mole = 1/2 mole. Convert this to grams using the molecular weight: 1/2 mole x (74.1 g/mol) = 37.0 grams of diethyl ether. The percent yield is: 34.7 g/37.0 g = 0.938 or 93.8%
How could you differentiate methanol and ethanol with no lab equipment?
Smell is certainly the quickest way to distinguish ethanol from methanol but on the other hand my own brother had his olfactory bulb removed to rid him of a tumor. So for him the sense of smell is non-existant. The question is how to differentiate. There are a few things you could do if the purpose was simply to find out what you had as an experiment on its own. Let’s suppose my brother had two steel drums of alcohol - one methanol and one ethanol but the labels fell off. One way he could do it would be to boil some of it and note the behavior. My brother wouldn’t even need a thermometer!For instance if you added water to each compound and boiled them you would see a difference in just how they boiled. The methanol mix would begin to boil at the boiling temp and pressure for methanol. Then when the methanol was depleted he would see the boiling cease while the temperature rose to that of the boiling temp of water. Then it would begin to boil again until the water was gone.The ethanol/water mix on the other hand would begin to boil as a mixture and would not stop boiling until the mix was gone. This is because ethanol and water form an azeotrope with each other and methanol and water do not. Once an azeotrope is formed the boiling point of the mix is constantly changing during the boil and the boiling never ceases so long as heat is input. Both the ethanol and the water simultaneously evaporate together at ever changing ratios and the ethanol cannot be seperated thusly from water completely by boiling like methanol can. Of course if you have a thermometer this would make it more obvious but it is not necessary in such an experiment.Frankly in my home hobby lab the reason I often choose methanol is simply because it can be recovered to high purity through fractional distillation so easily. I also use isopropyl alcohol which is very cheap but it too forms an azeotrope with water so once used as a solvent it is simply cheaper to evaporate away or discard. It is possible to break azeotropes too but that would be a different question.
What are the mole fraction (X) and molality (m) of ethanol (C2H5OH) in an aqueous solution that is 5.0%...?
start with 100 ml of solution In 100 ml of 5.0% by volume solution there will be 5.0 ml ethanol 95 ml water mass ethanol = density x volume = 0.789 g/ml x 5.0 ml = 3.945 g moles ethanol = mass / molar mass = 3.945 g / 46.068 g/mol = 0.08563 moles mass H2O = density x volume = 1.00 g/ml x 95 ml = 95 g = 0.095 kg moles H2O = mass / molar mass = 95 g / 18.016 g/mol = 5.273 moles molality = moles solute / kg solvent = 0.08563 moles / 0.095 kg = 0.90 m mole fraction ethanol = moles ethanol / total moles in solution = 0.08563 mol / ( 5.273 mol + 0.08563 mol) = 0.016
Biology packet question please help?
I need help on this question in my bio packet. Thank-You in advance: Scientists have been experimenting with different forms of alternate energy to help reduce the amount of fossil fuels that are burned. They studied yeast, which convert plant materials into ethanol, a form of alcohol that can be used in automobiles. These experiments were carried out at room temperature. The scientists wondered whether more ethanol would be produced at different temperatures. Design an experiment to determine the effect of temperature on ethanol production by yeast. In your answer be sure to: 1. State one hypothesis the experiment would test 2. State how the control group would be treated differently from the experimental group 3. Identify two factors that must be kept the same in both the experimental and control groups 4. Identify the independent variable in the experiment Please help! I'm stuck on this one! Thank-You!
In a chem lab, why do I have to use ethanol and distilled water to rinse solid copper that I will have filtered from a solution of zinc chloride and zinc sulfate?
Because you are washing any impurities off of it. The water dissolves some impurities, and the ethanol will dissolve other impurities. Doing both rinses will get the purest sample. The water wash must be done first because the ethanol will remove any residual water and the ethanol will evaporate quickly leaving a pure sample.
Why do people consume only ethanol and not other types of alcohol?
The other types of alcohol (other than ethanol) are poisonous to humans.Please don’t try to save money or experiment with other alcohols (i.e. Methanol or wood alcohol) by consuming them. You won’t like the results.
Explain,with the aid of an equation, why water should not be used to dilute ethanol?
It is an experiment to determine the rate of reaction bet sodium and ethanol.So a piece of sodium was added to a large excess ethanol... Now the experiment is modified and the concentration of ethanol is changed,so why water cannot be used to dilute the ethanol???
Density formula question, I guess? Is this right!?
this is why I teach "factor label method" aka "dimensional analyis".. look at the simplicity of this answer.... 15.0 g ETOH x (1 mL ETOH / 0.789 g ETOH) = 19.0 mL ETOH ************* notice that I have units of g ETOH / g ETOH... that cancels. leaving mL ETOH... I highly recommed you learn this technique. It will make your chemistry life much easier. here's a couple of links you can read if you need help... http://www.chem.tamu.edu/class/fyp/mathr... my answer here... http://answers.yahoo.com/question/index;...