Question 30Acetylsalicylic acid is a pain relief medication also known as aspirin. The purityof an aspirin tablet was determined by titration against a basic standard.First, the basic solution was standardised by titrating it with a standard solutionof potassium hydrogen phthalate:KHC&H4O4(aq) + NaOH(aq) → H½O(1) + NaKCsH404(aq)An average titre of 19.25 mL of the sodium hydroxide solution was required toreach equivalence with 25.0 mL of 0.0116 M potassium hydrogen phthalate.One aspirin tablet was weighed and found to have a mass of 0.370 g.It was dissolved in deionised water and made up to 250.0 mL in a volumetricflask.The standardised NaOH solution was titrated against 25.0 mL of the aspirinsolution:C9H$O4(aq) + NaOH(aq) → H2O() + NaC»H7O4(aq)The average titre of NaOH that neutralised the aspirin solution was 13.20 mL.(a) Explain why dissolving a precisely known mass of solid NaOH and makingthe solution up250.0 mL in a volumetric flask is not an appropriate wayto prepare a standard solution.(b) Identify the most appropriate piece of equipment for collecting precisely25.0 mL of the dissolved tablet solution.Question 30 continuesQuestion 30 (continued)(c) Calculate the concentration of the standardised NaOH solution.(d)Given that the molecular mass of aspirin is 180.158 g mol1, calculate thepurity of the tablet as %w/w.

Volumetric flask is used for preparing a fixed volume of solution. Like for preparing 250 ml…

(a) Explain why dissolving a precisely known mass of solid NaOH and making the solution up to 250.0 mL in a volumetric flask is not an appropriate way to prepare a standard solution. (b) Identify the most appropriate piece of equipment for collecting precisely 25.0 mL of the dissolved tablet solution. Question 30 continues Question 30 (continued) (c) Calculate the concentration of the standardised NaOH solution.

(a) Explain why dissolving a precisely known mass of solid NaOH and making the solution up to 250.0 mL in a volumetric flask is not an appropriate way to prepare a standard solution. (b) Identify the most appropriate piece of equipment for collecting precisely 25.0 mL of the dissolved tablet solution. Question 30 continues Question 30 (continued) (c) Calculate the concentration of the standardised NaOH solution.

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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Consider the reaction of Potassium Phosphate and Nickel (II) Bromide, where 15.00 ml of 0.7000M K3PO4 is mixed with 15.00ml of 0.2000M NiBr2 (and the final volume is 30.00 ml, that is there is no change in volume upon mixing). Your answer has to include all of the following: What is the limiting reagent? What is the identity and mass of precipitate formed? What is the concentration of the alkali metal that is a spectator ion? What is the concentration of the excess phosphate?
A sample weighing 0.2500g contains chloride ions, which precipitate as silver chloride. The formed precipitate has a weight of 0.7476 g. What is the percentage concentration of chlorides?
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(a) You are about to prepare three solutions of 0.5 M KI, 0.01 M K2S2O8, and 0.01 M Na2S2O3*5H2O in 250 mL volumetric flasks. - Describe how you will go about this, i,e, explain all steps of weighing of solutes, volumetric measurements (filling up with deionised water) ect. Calculate what mass of solute you will need in each of solutions mentioned above that you need to prepare. Show all calculations steps. (b) You are also tasked to fill burettes with the above-mentioned solutions, however, after filling up the solutions, you realised that there is a bubble towards the bottom tip inside the burette. Is it wise to continue with the experiment, while there is a bubble, if NOT explain why. (c) According to the manual's Experimental procedure, one conical flask (flask 1) contains a mixture of 20 mL of the KI solution plus 10 mL of the Na2S2O3 solution, while in the second flask (flask 2) there is 20 mL of the K2S2O8 solution with added five drops of starch solution. Why can't you add…
The equation for dilution of a solution is ?1?1=?2?2M1⁢V1=M2⁢V2 where ?1M1 and ?1V1 are the initial concentration and volume, respectively, and ?2M2 and ?2V2 represent the final concentration and volume, respectively. When preparing a dilute solution, it is necessary to first calculate the volume of stock solution needed. Which of the expressions is equal to the volume of stock solution, ?1?V1? ?2?2?1M2⁢V2M1 ?1?2?2M1⁢M2V2 ?2?1?1
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A stock solution of potassium permanganate (KMnO4) was prepared by dissolving 17.1 g KMnO4 with DI H2Oin a 100.00-mL volumetric flask and diluting to the calibration mark. Determine the molarity of the solution.
Normally, the amount of silver nitrate required to precipitate all of the chloride in the sample is found by a trial and error process. However, to speed up the experiment, assume a sample mass of 0.1431 g, and that sample contains approximately 55.0% chloride ion by mass. From these assumptions, calculate the volume of 0.100 M AgNO3(aq) that needs to be added to precipitate all of the chloride ion. Please answer in mL. (Note: You are calculating the exact amount required and not adding 5mL in excess. In the experiment, you'd be adding an additional 5mL in excess since the chloride value of the salt may exceed 55%. Pay attention to the sig. figs. in your calculation; keep three sig. figs. in the answer.)
Use the direct addition method. Use the References to access important values if needed for this question. A student wishes to prepare 125-mL of a 0.172 M nickel(II) sulfate solution using solid nickel(II) sulfate, a 125-mL volumetric flask, and deionized water. (a) How many grams of nickel(II) sulfate must the student weigh out? g (b) Which of the following would NOT be an expected step in the procedure used by the student? O Add a small amount of water to the volumetric flask and swirl until the salt sample has dissolved. O Stopper the flask and invert it to mix the contents. O Carefully weigh the flask. Check & Submit Answer Show Approach 山T@ étv A hulu
[Review Topics] [References] Use the References to access important values if needed for this question. An aqueous solution of ammonium acetate, NH, CH3COO, is made by dissolving 8.30 grams of ammonium acetate in sufficient water in a 100. mL volumetric flask, and then adding enough water to fill the flask to the mark. What is the weight/volume percentage of ammonium acetate in the solution? Weight/volume percentage = % Submit Answer Retry Entire Group 4 more group attempts remaining Previous Email Instructor Next Save and Exit