Prepare Aspirin Solutions 1. Record the concentration ofthe NaOH solution. Ithas

Question

Prepare Aspirin Solutions 1. Record the concentration ofthe NaOH solution. Ithas been standardized by your TA .11M 2. Simultaneously prepare two of the following solutions 3. obtain the mass of an aspirin tablet and add it to an Erlenmeyer flask. .366g 4. Using a 50mL volumetric pipette, add 50.00mL of NaoH to the tablet in the flask. 5. Heat the flasks in a hot water bath (near boiling for 5 minutes. (big beaker with water in it). While you are wating standardize the HCI. Standardize HCI 6. obtain 0.05 to 0.1gof Nazco, (record the mass) and additto an Erlenmeyer flask. .055g 7. Add approximately 25 mLofdeionized water and 3 drops of phenol red to the flask to dissolve the NazCO, 8. Prepare a burette with the HCI solution-rinse burette and tip, fill burette, run bubbles out of tip, record initial volume. 9. SIowly add the HCI to the flaks with the Nazco, until the end point is reached. Record the final volume of HCI. 10, Repeat (add more HCI to burette if necessary before you begin). V (initial 21.2 V (Final) 30.41 Titrate Aspirin Tablets 11. Refill the burette with the HCI solution 12. Add a few drops of phenol red to the flasks with the aspirin. V (initial) 23.1 13. Titrate your aspirin samples in the flasks with the HCI solution. V (final) 43.2

Explanation / Answer

moles of Na2CO3 used =0.055g/106g/mol = 5.19*10^-4 moles

Molarity of na2Co3 solution = 5.19*10^-4 moles/0.025 L = 0.021 M

volume of HCl added = 30.41-21.2 = 9.21 mL

M1V1 = M2V2

where M1 and V1 is the molarity and volume of HCl . M2and V2 is the molarity and volume of naOH

M1 * 9.21mL = 0.021 M * 25 mL

or, M1 = 0.057 M

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