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The following is a description of an experiment in which ethyl benzoate is hydrolyzed. 5cm (0.03 moles) of ethyl benzoate are mixed with 30cm3 of 2M NaOH solution and heated under reflux for about 15minutes until all the oily drops have disappeared. The flask is then filled for fractional distillation and the mixture distilled until the boiling point reaches 750 to give a distillate "A".
The content of the flask is allowed to cool and then slowly acidified with concentrated hydrochloric acid when a precipitate "B" separates. This precipitate is purified by recrystallization from water.
a. Describe how you would separate and recrystallize the precipitate B. Indicate the apparatus
b. State how you would check that your recrystallized speciment is pure.
The following is a description of an experiment in which ethyl benzoate is hydrolyzed. 5cm (0.03 moles) of ethyl benzoate are mixed with 30cm3 of 2M NaOH solution and heated under reflux for about 15minutes until all the oily drops have disappeared. The flask is then filled for fractional distillation and the mixture distilled until the boiling point reaches 750 to give a distillate "A".
The content of the flask is allowed to cool and then slowly acidified with concentrated hydrochloric acid when a precipitate "B" separates. This precipitate is purified by recrystallization from water.
a. White is the white precipitate B?
b. Write the equation for its formation
The following is a description of an experiment in which ethyl benzoate is hydrolyzed. 5cm (0.03 moles) of ethyl benzoate are mixed with 30cm3 of 2M NaOH solution and heated under reflux for about 15minutes until all the oily drops have disappeared. The flask is then filled for fractional distillation and the mixture distilled until the boiling point reaches 750 to give a distillate "A".
The content of the flask is allowed to cool and then slowly acidified with concentrated hydrochloric acid when a precipitate "B" separates. This precipitate is purified by recrystallization from water.
a. What is the liquid A?
b. Give the chemical test and its results which would support your answer in (a.)
The following is a description of an experiment in which ethylbenyoate is hydrolysed. 5cm (0.03 moles) of ethylbenzoate are mixed with 30cm3 of 2M NaOH solution and heated under reflux about 15minutes until all the oily drops have disappeared. The flask is then filled for fractional distillation and the mixture distilled until the boiling point reaches 750 to gwe a distillate "A".
The content of the flask are allowed to cool and then slowly acidified with concentrated hydrochloric acid when a precipitate "B" separates. This precipitate is purified by recrystallisation from water.
a Write the equation for the reaction between ethylbenzoate and NaOH solution
b. Sketch the apparatus for heating the mixture under reflux
c. During distillation, where would you keep the bulb of the thermometer and why?
Benzoic acid is manufactured by the decarboxylation of phthalic anhydride (C8H4O3). Steam is passed through molten anhydride, containing a metallic catalyst.
What is meant by decarboxylation?
Give the structure of benzoic acid
Benzoic acid is manufactured by the decarboxylation of phthalic anhydride (C8H4O3). Steam is passed through molten anhydride, containing a metallic catalyst.
Suggest a structure for phthalic anhydride. Hence write an equation for the reaction.
Calculate the molar mass of the following compounds. Show your work.
Water, H2O
carbon dioxide, CO2
sodium chloride, NaCl
calcium hydroxide, Ca(OH)2
potassium permanganate, KMnO4
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A chemist adds 105.0mL of a 0.817mol/L sodium carbonate Na2CO3
solution to a reaction flask. Calculate the mass in grams of sodium carbonate the chemist has added to the flask. Round your answer to 3 significant digits. please show steps thank you
In a flexible-walled container, 300 L of gas is prepared at 600 mm Hg and 200 oC. The gas is placed in a tank under high pressure. When the tank cools to 20 oC, the pressure of the gas is 30 atm. What is the new volume of the gas?
