chem 110 experiment 12 tritation vinegar
need help fast please!!!
The density of vinegar is 1.01 g/mL. How would this information
affect your experimental results.
2. Weak acids, such as acetic acid, typically have an odor, whereas
strong acids often do not. Explain this is so
EXPERIMENT # 1 2 ACETIC ACID CONTENT OF VINEGAR Objectives Use chemical pll indicators to find endpoints of acid base titrations Use the burets to undertake chemical titrations PreLab questions i. Lab. If commercial vinegar is 10.0% HCHO by mass, what is the molarity of the acid? utation. How many ml of 0.150 M HCI are needed to completely react with 1.00 g of Na CO, (products are NaCI, H:O and CO.) 3. Context. The acetic acid content of vinegar is your subject for analysis by titration. In this experiment, the reagent solution contains sodium hydroxide of known concentration, which reacts with the acetic acid portion of the vinegar. The sodium hydroxide solution of known concentration is slowly added from a buret until all of the acetic acid has been neutralized. A chemical indicator called phenolphthalein, which is colorless in acid solutions and pink in basic solutions, signals the endpoint of the titration. In the untitrated sample, the phenolphthalein is colorless. At the endpoint of the titration, the phenolphthalein has just turned pink. You will need the following information in order to obtain the percent of acetic acid: 1. VOLUME OF NaOH USED TO TITRATE 2. CONCENTRATION OF THE NaOH SOLUTION 3. WEIGHT OF THE VINEGAR SAMPLE. To simplify matters, assume that the density of vinegar is 1.00 g/mL PROCEDURE 1. Rinse two burets with deionized water. The test for a clean buret involves filling the buret with water, then letting the water run out, and seeing whether or not any drops of water adhere to the walls of the buret (No water should adhere to the buret). 2. Rinse one of the clean burets with a small (5 mL) amount of vinegar solution. Allow mL to drain out the tip, and then, while rotating the buret slowly, pour the remainder out the top. Fill the buret with only 10 mL vinegar. Be sure that the tip of the buret is also filled, and that there are no air bubbles. 3. Repeat the process with NaOH and the other buret (only fill the entire buret with NaOH not just 10 mL). Put both burets on a holder, secured to a ring stand. 4. Obtain a clean 125-mL (or 250-mL) Erlenmeyer flask and allow approximately 2.5 mL (read buret to nearest ±0.01 mL) of vinegar to flow into the flask from the buret. NOTE: TAKE ALL BURET READINGS TO THE NEAREST +0.01 mL. NOTICE THAT A BURET READS IN A DIRECTION OPPOSITE TO THAT OF A GRADUATED CYLINDER (ZERO AT THE TOP). You now have an approximate 2.5 g sample of vinegar in your flask. Record weight. If you allowed a little more or less vinegar to flow into the flask, it is all right. Just make sure you record the proper weight of the vinegar 5. Add about 25 mL of distilled water to the sample in the flask. NOTE: THIS WATER DOES NOT AFFECT YOUR SAMPLE OR THE TITRATION: IT JUST SERVES TO WASH THE SIDES OF THE FLASK AND MAKE THE ENDPOINT EASIER TO SEE Add two or three drops of phenolphthalein indicator solution to the flask. 6. Record the initial buret reading of the NaOH buret and then titrate your vinegar sample with the NaOH solution. YOU MUST USE AT LEAST 10.00 mL OF THE NaOH SOLUTION TO TİTRATE, OTHERWISE THE COMPUTER WİLL NOT ACCEPT YOUR DATA!!! The signal for the endpoint of the titration is a change in the color of the solution from colorless to pink. Record the final buret reading of the NaOH and determine the number of milliliters of NaOH used NOTE: PROCEED SLOWLY. YOU DO NOT WANT TO OVERSHOOT THE ENDPOINT. WITH PROPER TECHNIQUE, ONE DROP OF NaOH SOLUTION SHOULD CHANGE THE SAMPLE SOLUTION FROM COLORLESS TO PINK AS YOU REACH THE ENDPOINT. IF YOU DO OVERSHOOT THE ENDPOINT, YOU CAN STILL SALVAGE YOUR SAMPLE BY DOING THE FOLLOWING: 7. (A) Add additional vinegar to your flask from the vinegar buret until the phenolphthalein turns colorless. Swirl the flask to mix the contents. The weight of your vinegar sample has now been increased by the amount of vinegar you added. (B) Continue to titrate to endpoint with the NaOH solution. Record the final buret reading of the NaOH Perform two more titrations using fresh samples approximately the same size as your first sample. Questions he density of vinegar is 1.01 g/mL. How would this information affect your experimental results? eak acids, such as acetic acid, typically have an odor, whereas strong acids o Explain why this is so. ften do not.