Carefully work out solutions to the following problems, showing all calculations
ID: 1024643 • Letter: C
Question
Carefully work out solutions to the following problems, showing all calculations. In some cases you may find the chemical catalogs helpful. If you use extra paper, be sure to submit all. Answers w/o work receive no credit. Please be mindful of significant figures! What is the volume of 16.32 g of ethyl acetate? What is the mass of 300.0 mmol of benzoic acid? What is the volume of 450.0 mmol of glycerin? How many mmols is 0.750 g of E-stilbene (C_14 H_12)? A student obtained 0.525 g of E-stilbene from a reaction. The theoretical yield was 0.600 g, based on the reaction performed. What was his percent yield?Explanation / Answer
1. Volume of 16.32 g ethyl acetate
Volume = mass/density
with,
density = 0.902 g/ml
we get,
volume of ethyl acetate = 16.32/0.902 = 18.093 ml
2. mmol of benzoic acid = 300 mmol
moles = grams/molar mass
with,
molar mass of benzoic acid = 122.12 g/mol
So,
mass of benzoic acid = 0.3 mol x 122.12 g/mol = 36.63 g
3. mmol of glycerin = 450 mmol
with,
density of glycerin = 1.26 g/ml
molar mass of glycerin = 92.1 g/mol
we get,
Volume of glycerin = (450 mmol x 92.1 g/mol)/(1000 x 1.26 g/ml) = 32.90 ml
4. moles = gram/molar mass
with
molar mass of E-stilbene = 180.24 g/mol
we get,
mmols of E-stibene = 0.750 g x 1000/180.24 g/mol = 4.16 mmol
5. Percent yield = (yield obtained from experiment/actual yield) x 100
= (0.525 g/0.600 g) x 100
= 87.50%