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. If you measure 68.0 g of ethanol, how many milliliters of ethanol do you have?

ID: 713841 • Letter: #

Question

. If you measure 68.0 g of ethanol, how many milliliters of ethanol do you have? (Density of ethanol is 0.789 g/mL) *Show all work for full credit (Use correct significant figures and units) 8. You start off with 4.9 g of a substance and purify it by a given method. After purification, you have 1.5 g of the purified substance. What is your percent recovery? *Show all work for full credit 9. The following is a reaction you will see in second semester organic chemistry. The molecular weight of methyl benzoate is 136.16 g/mol and the molecular weight of the product is 181.15 g/mol. COCH3 COCH3 HNO H2SO4 NO2 methyl benzoate methyl 3-nitrobenzoate Assume you have excess acid and you start off with 3.4 g of methyl benzoate. a) What is the theoretical yield (in grams) of methyl 3-nitrobenzoate? *Show all work and BOX your final answer. Significant figures and units count. b) I n lab, your final product weighs 2.0 grams. What is your percent yield? "Show all work for full credit

Explanation / Answer

7. As we know that density (d) = mass(m)/volume (v)

Volume (v)= m/d= 68/0.789= 86.18 g/ml

8. Percent purity= pure compoundx100/crude compound

= 1.5x100/4.9= 30.61%

9. A. Moles of methyl benzoate= 3.4/136.16= 0.0249 mole

Theoretical yield = moles of methyl benzoate x molar mass of product

= 0.0249x 181.15=4.51 g

B. Percent yield= observed yield x100/theoretical yield

= 2x100/4.51

= 44.34 %