Lab Exam. Flashcards
What is the structure of salicylic acid?
What is the structure of aspirin?
What is the reaction for salicylic acid with acetal chloride/pyridine?
What is the reaction for aspirin with acetal chloride/pyridine?
What is the reaction for salicylic acid with methanol/HCl/heat?
What is the reaction for aspirin with methanol/HCl/heat?
What is the reaction for salicylic acid with sodium bicarbonate at room temperature?
What is the reaction for aspirin with sodium bicarbonate at room temperature?
What is the reaction for salicylic acid with thionyl chloride?
What is the reaction for aspirin with thionyl chloride?
What is the reaction for salicylic acid with 10% sodium hydroxide at room temperature?
What is the reaction for aspirin with 10% sodium hydroxide at room temperature?
What is the reaction for salicylic acid with excess sodium hydroxide at room temperature?
What is the reaction for aspirin with excess sodium hydroxide at room temperature?
What is the reaction for salicylic acid with ammonium hydroxide at room temperature?
What is the purpose of phosphoric acid in the aspirin lab?
It acts as a catalyst which will quicken the reaction by protonating the carbonyl group on the anhydride.
What is the purpose of water in the aspirin lab?
Water removes any excess acetic anhydride.
What is the purpose of ice in the aspirin lab?
Ice accelerates crystallisation and increases the yield of the product. It also precipitates the aspirin which is then recrystallised to water.
What is the purpose of ethanol in the aspirin lab?
To purify and dissolve the crystals.
For the caffeine lab, how do you calculate the percent recovery?
Actual yield * 100% / theoretical yield. Actual yield is the mass of caffeine. Theoretical yield is the mass of caffeine * mass of tea bags.
In the caffeine lab, suppose you forgot to add sodium carbonate to the tea solution prior to extraction?
The sodium carbonate acts as a base. When you boil tea, tannins and caffeine dissolve in the water. If a base is not used then the tannins will be extracted into the solvent. The base converts the tannins into sodium salts which are ionic and are not soluble so will remain in the aqueous layer and allow pure caffeine to be extracted.
What is the equation for ethanol with Na?
What is the equation for ethanol with NaOH?
CH3-CH2-O(-)-Na(+) and H2O
What is the equation for ethanol with Na2CO3?
No reaction
What is the equation for phenol with Na?
Picture
What is the equation for phenol with NaOH?
Picture
What is the equation for phenol with Na2CO3?
Picture
What is the equation for ethanoic acid with Na?
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What is the equation for ethanoic acid with NaOH?
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What is the equation for ethanoic acid with Na2CO3?
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In the ethyl acetate lab what is the equation for the formation of ethyl acetate?
CH3CH2OH + CH3COOH = CH3COOCH2CH3 + H2O
In the ethyl acetate lab, what is the purpose of sulphuric acid?
The sulphuric acid is used because it will catalyse the esterification reaction. It also removes a water molecule from the reaction and is therefore responsible for the dehydration reaction.
In the ethyl acetate lab, what happens if water is removed from the reaction mixture?
If water is removed from the reaction, the overall equilibrium of the reaction will shift to the right which will form more products. If more products are formed the system will reach equilibrium.
In the ethyl acetate lab, what products are formed when ethanol is oxidised by sodium dichromate?
CH3-COOH
What is the reaction for aspirin with ammonium hydroxide at room temperature?
