I am writing up a lab to perform in school. My first submission was denied and I
ID: 1003001 • Letter: I
Question
I am writing up a lab to perform in school. My first submission was denied and I was told I need to explain the grams KHP I would need to use (must be under 0.5g) and I would need roughly 15 mL NaOH- but I need to show the calculations and I have no idea where to start or what this means. Can someone write up a calculation for me and explain? I was also told I need to find the average amount of tartaric acid in wine and give an amount in mL for testing. For this the average amount of tartaric acid in wine needs to be found and an appropriate volume needs to be calculated (aiming at using 15mL NaOH) EXPERIMENTAL DESIGN So, your task is to design an experiment (or a series of experiments) to quantitatively determine the total acidity in two samples of al acidity in two samples of wine (one domestic, one imported) given to you by your instructor. Design an experimentar signed approvall receive signed approval tructor. Design an experimental plan and a data sheet on which to record the appropriate measurements. You must (le., initials) for your written experimental plan and data sheet from your in s) for your written experimental plan and data sheet from your instructor before proceeding. The materials and equipment available to you are Buret Titration flask Magnetic stirrer pH electrode Analytical balance Volumetric pipets Approximately 1 M NaOH solution KHP LabPro interface, transformer, cable Phenolphthalein Wine samples, domestic and imported In developing your plan consider the following: a. What type of experiment have you used in past labs to analyze the concentrations of acid in a solution? b. What should be the stoichiometric ratio in the reaction between tartaric and malic acids and sodium hydroxide? (Hint: write the balanced equations) c. Is the sodium hydroxide ready to use in a quantitative determination? d. What volume of wine should be used for each titration? To decide this, go to the internet or a reference book and find the approximate concentration of acid in wine th use the data to compute the appropriate sample size. Use a sample size that will require 15 to 20 mL. of sodium hydroxide.
Explanation / Answer
Lets say we have 1 M NaOH solution
To standardize this NaOH we used KHP
1 mole of KHP reacts with 1 mole of NaOH
with 15 ml NaOH we would need = 1 M x 0.015 L x 204.22 g/mol = 3.06 g of KHP for titration
Once NaOH is titrated and exact concentration is calculate for NaOH, it is titrated with Tartaric acid in wine solution.
Lets say we have used 15 ml of 1 M NaOH for the titration of 10 ml wine sample
2 moles of NaOH are needed to titrated with 1 mole of tartaric acid
moles of NaOH used = 1 M x 0.015 L = 0.015 mol
concentration of tartaric acid in wine sample = moles/L = 0.015 mol/0.010 L = 1.5 M
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