Course Hero is not sponsored or endorsed by any college or university. 2. At your bench add about 50 ml of distilled water to KHP sample #1. Explain each answer. However, the solid NaOH is hygroscopic (easily absorb moisture from air.) Thus, the actual concentration of the NaOH solution has to be determined experimentally using a process called standardization. 2. 2. Some KHC8H4O4 is spilled out of the flask after it is weighed. This preview shows page 3 out of 3 pages. In addition, the carbon dioxide that is naturally dissolved in water further changes the basicity of the solution. Puoi modificare le tue preferenze in qualsiasi momento in Le tue impostazioni per la privacy. This would result in a higher number of. A. Sodium Hydroxide Solution Standardization. Add 2 drops of phenolphthalein indicator. A decreased value of NaOH concentration would, require a larger volume of NaOH for the titration. 4.000 g is after all 0.1000 mole of NaOH, so dissolving it in one litre of water should produce a one litre solution. solution was not exposed to air. Since this time of exposure occurred after the standardization, you, would still be using the concentration calculated before. 4. Accurately weigh about 0.5 g of potassium biphthalate, previously crushed lightly and dried at 120° for 2 hours. Informazioni su dispositivo e connessione Internet, incluso l'indirizzo IP, Attività di navigazione e di ricerca durante l'utilizzo dei siti web e delle app di Verizon Media. The buret is rinsed with water, but not NaOH solution before it is filled. the molar mass would be too low because it would have a lower volume Some solution splashes out of the flask during titration. D. STANDARDIZATION OF THE NaOH SOLUTION 1. Keep the solution for at least an hour and then carry out the standardization. Swirl to dissolve the KHP completely. The most important value for the acid is, If the buret had been rinsed with deionized water and then filled with NaOH solution, without having been rinsed with the NaOH solution first, the calculated molar mass would, be lower. The NaOH solution would, react with carbon dioxide from the atmosphere, which would result in a lower concentration, of NaOH than before. B. exposing NaOH solution to the air: a) would the calculated molar mass be too high or too low if your standardized NaOH were exposed to the air for a long period of time after the standardization? The volume of the NaOH solution in the buret would increase, resulting in a, decreased value for molarity of NaOH. The calculations would result in a similar molar mass. Per saperne di più su come utilizziamo i tuoi dati, consulta la nostra Informativa sulla privacy e la nostra Informativa sui cookie. The water was simply used to dissolve, the acid. When it is exposed to the air, the concentration would increase because it would mix with other elements that are found in the air. 1.   Terms. If the NaOH was, exposed to air before the standardization of NaOH, then you would be able to calculate an, accurate number for the concentration of NaOH. Titrating to find the molar mass of an unknown acid. NaOH molar solutions always have to be standardized before you can use them in a titration. The calculated molar mass would be too high if the standardized NaOH were exposed to the air for a long period of time after the standardization. Since the concentration is lower, you, would need to use a larger volume of NaOH than you would have needed if the NaOH. The volume of the acid is not important. the solution produce. The calculated molar mass would not change if the standardized NaOH solution were, exposed to air for a long period of time before the standardization. 3. San Diego State University • CHEMISTRY 200, Copyright © 2020. The calculated molar mass would be too low if the standardized NaOH solution were exposed to air for a long period of time after the standardization. A The calculated molar mass would be too low if the standardized NaOH solution, A. Course Hero, Inc.   Privacy Consider the effect of exposing the NaOH solution to the air. of the buret is filled with solution and that there are no air bubbles. A.How would your calculated molarity of the NaOH solution be affected (too high, too low, no change) by each of the following errors? needed to perform this titration. However, it is very difficult to prepare a solution of NaOH of an exact concentration for two reasons: Solid NaOH is very hygroscopic, that is it absorbs water from the air, so … The calculated molar mass would be too low if the standardized NaOH solution were, exposed to air for a long period of time after the standardization. Noi e i nostri partner memorizzeremo e/o accederemo ai dati sul tuo dispositivo attraverso l'uso di cookie e tecnologie simili, per mostrare annunci e contenuti personalizzati, per la misurazione di annunci e contenuti, per l'analisi dei segmenti di pubblico e per lo sviluppo dei prodotti. moles of acid, which means a lower molar mass. If you use NaOh exposed to air to make a molar solution, your solution will probably be too weak. You would calculate a larger number of moles of acid, and. Per consentire a Verizon Media e ai suoi partner di trattare i tuoi dati, seleziona 'Accetto' oppure seleziona 'Gestisci impostazioni' per ulteriori informazioni e per gestire le tue preferenze in merito, tra cui negare ai partner di Verizon Media l'autorizzazione a trattare i tuoi dati personali per i loro legittimi interessi. since molar mass is g/mol, a larger number of moles would result in a lower molar mass. Yahoo fa parte del gruppo Verizon Media. The NaOH solution would react with carbon dioxide from the atmosphere, which would result in a lower concentration of NaOH than before. Dissolve in 75 ml of carbon dioxide free water. a) Would the calculated molar mass be too high or too low if your standardized NaOH were exposed to air for a long period of time after the standardization? A larger volume of NaOH will be. When you try to mass the NaOH, you will also be massing the water absorbed by the NaOH, therefore your molar solution will not be as strong as you think it is. If you had used 50mL of water instead of 25mL, the accuracy of the molar mass would not, be significantly affected by that change in procedure. With water, but not NaOH solution has to be standardized before you can use them in lower! In 75 ml of distilled water to KHP sample # 1 moles would result in a titration solution! And then carry out the standardization not sponsored or endorsed by any college or University from.. 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