1.Explain how you will ensure that the titration is carried out accurately The burette and pipette I’m going to be using should be rinsed out with the solutions they are going to contain. After filling the titrant solution, I have to check the tip of the burette for any air bubbles, if it contains air bubbles the volume readings will be incorrect. Always rinse out the conical flask with distilled water because normal tap water contains ions, this will affect my results. Tap water have chemicals while distilled water is deionized, this simply means there will be no ions. When pipetting the solution into the flask, I have to let the pipette drain under gravity and then touch the surface of the liquid with the tip of the pipette. This ensures that exactly the correct volume has been added. Remove the funnel from the burette, because the remaining solution that is left on top of the burette might drop into the burette. This will give an incorrect titration result. I placed a white tile under the flask so when the colour changes I would be able to see it clearly and easily. During the experiment, it was very important to swirl the solution continuously in the conical flask, if the solution isn’t swirled I would not get an accurate end-point. Washing the sides of the …show more content…
A pH meter is an instrument or device which measures acidity or alkalinity of a fluid. pH meter is a suitable instrument for measuring the pH of a solution because it is quick and simple to use. The instrument contains few buttons to operate so the end result will be given quickly displayed on the pH screen. The results are precise and it is correctly calibrated. The meter is portable and it can be used in different fields such as school or industries. People do not need extensive training since it is easy to use. Only small amount of solution is needed for measuring the pH. pH meter is much better than using indicator because when using indicators, the colour change will be seen at different
Then, I added 8 drops of concentrated phosphoric acid to the mixture. swirling it a few times. Then, I carefully took the flask to the station as I avoided trying to breath the vapors of the acetic anhydride. I put the e-flask into the beaker of water sitting on the hot plate in order to heat it for seven minutes. Once the seven minutes was up, my partner carried the e-flask to the fume hood, and added 3 mL of de-ionized water to the flask. She swirled it for a couple of minutes there. She brought it back tot he station where I gradually added 60 Ml of de-ionozed water to the mixture while my partner stirred the mixture constantly. I was able to see some of the aspirin beginning to form. In order to complete the crystallization process we cooled the flask in an ice-water bath from 4:00 until 4:20. As we waited I began to set up our filtration system. I used a ring stand, right angel clamp, three finger clamp, Buchner funner, filtering flask,rubber tubing, and filter paper in the Buchner funnel. I turned on the aspirator and pored some water over the filtering paper in order to create a good
There are a few changes that should be made to the procedure so that the experiment could generate better results. More time should be allowed to dissolve the tablets as if they are not dissolved colour changes are harder to identify during the titration and also the results are less accurate. The acid used should also be more concentrated as a 0.5mol or 0.3mol would mean a smaller amount of acid would be required.
3. Add on of the following volumes of distilled water to the test tube, as assigned by your teacher: 10.0mL, 15.0mL, 20.0mL, 25.0mL, 30.0mL. (If you use a graduated cylinder, remember to read the volume from the bottom of the water meniscus. You can make more a more accurate volume measurement using either a pipette or a burette.)
Read the initial buret readings for both burets to the nearest 0.01 ml. Use a buret reading card to make the meniscus more prominent. Record readings on the report sheet. Have your instructor check and initial your report sheet for your first buret reading (sample #1, only). 6. Rinse a clean 125 ml Erlenmeyer flask with deionized water. Deliver approximately 20 ml of unknown acid into the Erlenmeyer flask. The tip of the buret should be approximately 1/2 inch below the top of the flask to avoid loss due to splashing. 7. Add 2 or 3 drop of phenolphthalein indicator. (Above your lab bench). 8. Titrate the unknown acid by adding standard NaOH (from the buret). Swirl the flask to mix the solutions during the addition of base. As the base is added you will observe a pink color localized at the spot the NaOH enters the solution (this is due to a localized high base concentration). Occasionally, rinse down the walls of your flask with deionized water (This rinses down any acid that has splashed onto the walls of your flask). Near the end-point, the pink color "flashes" throughout the solution and remains for a slightly longer time (1-2 seconds). When this occurs, add the NaOH drop by drop and eventually half-drops until the pink color remains (for at least 30 seconds). This is the end-point! NOTE: If you over-shoot the end-point (too much NaOH is added), add 1-2 more ml of the Unknown acid and then add NaOH again until a proper end-point is reached. Be sure
In this experiment, there were several objectives. First, this lab was designed to determine the difference, if any, between the densities of Coke and Diet Coke. It was designed to evaluate the accuracy and precision of several lab equipment measurements. This lab was also designed to be an introduction to the LabQuest Data and the Logger Pro data analysis database. Random, systematic, and gross errors are errors made during experiments that can have significant effects to the results. Random errors do not really have a specific cause, but still causes a few of the measurements to either be a little high or a little low. Systematic errors occur when there are limitations or mistakes on lab equipment or lab procedures. These kinds of errors cause measurements to be either be always high or always low. The last kind of error is gross errors. Gross errors occur when machines or equipment fail completely. However, gross errors usually occur due to a personal mistake. For this experiment, the number of significant figures is very important and depends on the equipment being used. When using the volumetric pipette and burette, the measurements are rounded to the hundredth place while in a graduated cylinder, it is rounded to the tenth place.
Check if there are any leaks especially around the stopcock, the valve at the bottom of the buret. When it comes to calibration, it is calibrated by transferring water into an Erlenmeyer flask and weighing it using an analytical balance. This is done for two (2) trials, each with varying amounts of water. Erlenmeyer’s mass is pre-recorded before transferring water from the buret. The volume delivered by the buret is considered the apparent, which means evident, volume. Before starting another set, the flask should be clean and dry to avoid any error. The water inside the flask will add the volume to be transferred thus making the mass of water higher than what it should really be. The mass of water obtained thru weighing by difference would then be multiplied to the buoyancy of water at the recorded temperature which will then be the corrected mass of the water. The corrected mass of the water is then divided by the density of the water, at the same temperature, and will be considered as the true mass. Correction value can be obtained by solving for the difference between the true volume and the apparent volume. Some of the correction value computed are negative and it only means that there is an error that occurred. One of the possible errors in most volumetric glassware’s is reading the wrong volume. Volume must be read based on the lower meniscus at eye
As the bottom of the meniscus in the measuring cylinder should be read at horizontal eye level, there will be some variation between trials as participants cannot insure they are looking at the scale at a horizontal level each trial measurement. When the contributor views the meniscus at a horizontal eye level but slightly above the horizontal without realising it, the value would become less, causing recording of a lower volume. Vice versa, when viewing the meniscus in a position below the horizontal, the reading of the scale would be larger than the correct volume. Parallax error occurring during measurement, makes the concentration of the acid
3.) Divide your 30g of white substance into the 4 test tubes evenly. You should put 7.5g into each test tube along with the water.
The pH meter needed to be calibrated before the titration, and this was done by using coloured standards of pH 4.0, 7.0 and 10.0. The NaOH used within this practical was measured out in pellet form, and the amount needed was 0.4g of 0.1M NaOH. The NaOH was then dissolved into 100ml of distilled water by using a magnetic stir bar and a magnetic stirrer, which mixed the solution for around 120 seconds. After the NaOH had been dissolved, 25ml of 0.1M CH3COOH was measured into a measuring cylinder and was then transferred into a 100ml beaker. This was also placed onto the magnetic stirrer and a clean magnetic stirrer bar was then added to avoid any contamination before the NaOH had been added. The calibrated pH meter was then added to the CH3COOH and the initial pH reading was then taken, which was 2.8pH. By using a p200 pipette, 500µl aliquots of NaOH were then added to the CH3COOH solution, and 30 seconds were left between each aliquot to ensure the pH meter registered the changed pH. The pH of the solution was then recorded on a graph of pH vs volume of 0.1M NaOH added. After this, another 500µl (0.5ml) of NaOH was added and recorded until 40ml had been added (Thorne, A.
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.
I blended on high to make the potatoes more liquid-like. I grabbed the cheesecloth and placed on the top of the blender. I poured the potato extract on the container and labeled it. I found out that I have to make 1% sugar solution so I grabbed the sugar and measured into 5 grams on the scale. I added 5 grams of sugar on 250 ml graduated cylinder and poured the water into the cylinder. I mixed the sugar with water and poured it into the saucepan. I refilled the water into the graduated cylinder and poured into the saucepan. I turned on the heat of the stove and saw the sugar dissolved. I poured into a container and labeled 1% sugar solution. I repeated the same thing with 1% salt solution by using 1 gram of salt and filled the water into graduated cylinder by 100 ml. I answered question three. In the first experiment, I grabbed four transfer pipets and used it to put solutions into the test tubes by 3ml. I labeled it and placed into the plastic cups so it can stand upright. I grabbed each test tube and poured 2 ml of catalase solution into it. I also tapped and swirled to measure the bubbles by using the ruler. I wrote the numbers into the lab report. In the second experiment, I labeled the room
Rinse a 25mL buret with three 5mL portions of standard permanganate solution. Fill the buret with the standard permanganate solution and record initial and final readings.
Titration is a technological process in which a solution, known as a titrant, is slowly and carefully added from a burrette into a fixed volume of another solution (known as the sample). In an acid-base titration an acid neutralizes a base or vice versa. This process is maintained untill the reaction between the titrant and the sample (acid and the base) is judged to be complete. The reaction is judged to be complete when the endpoint is reached. An endpoint in a titration analysis is referred to as the point at which no more titrant is added due to an observable colour change of an indicator. Indicators can be used to find an endpoint because they change colour when the pH of a solution changes and an endpoint in a titration is an empirical approximation of the equivalence point, which is the point of major pH change in the titration sample due to the fact that equal chemical amounts of reactants have been combined at that point. All indicators have a pH range, which is the range of pH values at which the colour of the indicator changes. Thus
In this experiment we are trying to identify an unknown acid or base and its concentration by using the method of titration. The pKa values and the titration curve help aid in identifying of the unknown. In our case we had a base as our unknown (analyte). The use of a certain amount of sodium hydroxide and hydrochloric acid will be used to titrate the unknown solution that is given. This is the tirant. We used hydrochloric acid as our titrant. We achieved a pH of 5.56 at an end point of 10 milliliters. The unknown’s concentration was around 0.098 M at pka(s) of 6 and 7. The sodium hydroxide and hydrochloric acid are called titrant and it is contained in a container called burette. The unknown solution is held in an erlenmeyer flask. The purpose of the experiment is to measure the weak acid and base by neutrilizing it and determining the unknown acid by titration.
The purpose of this experiment is to use our knowledge from previous experiments to determine the exact concentration of a 0.1M sodium hydroxide solution by titration (Lab Guide pg.141).