Pages that need to be completed are 107,108 and 109. Page 105 and 106 are just background...

Question

Pages that need to be completed are 107,108 and 109. Page 105 and 106 are just background information.

Sannidhya · Accepted Answer

CHEM 1405 --- Titrating Vinegar Lab Report
Objective:
	To determine molarity and mass percent of acetic acid in a vinegar sample using titration against sodium hydroxide.
Theory:
	Vinegar is a solution of acetic acid in water. To determine the concentration of this acetic acid in the vinegar sample in molarity or mass percent, it is titrated against sodium hydroxide using phenolphthalein as an indicator. It is a neutralization reaction with the following stoichiometry:
			HC2H3O2 + NaOH  NaC2H3O2 + H2O
	The titration mixture is colorless initially, but as the endpoint is reached, i.e., sodium hydroxide and acetic acid react in 1:1 ratio, the mixture changes to a pale pink color. At this point, the moles of NaOH that has reacted provides the moles of acetic acid initially present in the vinegar solution, and thus its molarity or mass percent.
Materials and equipments used:
· NaOH solution of known concentration
· Distilled water
· Vinegar solution
· Phenolphthalein indicator
· Beakers
· Pipet
· Buret
Calculations:
Trial 1:
Volume of NaOH used = Final buret reading – Initial buret reading
			  = (43.75 – 0.50) ml = 43.25 ml = 0.04325 litre
Moles of NaOH required for titration = Molarity of NaOH * Volume of NaOH used (in liters)
					 = (0.4936M) * (0.04325 liter) = 0.02135 mol
Moles of HC2H3O2 in vinegar = Moles of NaOH required for titration
				= 0.02135 mol
Molarity of HC2H3O2 in vinegar sample =  
					     =  = 0.8540M
Mass of HC2H3O2 in vinegar = Moles of HC2H3O2 in vinegar * Molar mass of HC2H3O2 
			           = (0.02135 mol)*(60 g/mol) = 1.281g
Mass % of HC2H3O2 in vinegar =  
				    =  = 5.107%
Trial 2:
Volume of NaOH used = Final buret reading – Initial buret reading
			  = (43.60 – 0.40) ml = 43.

Pages that need to be completed are 107,108 and 109. Page 105 and 106 are just background information.

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