Unknown Diprotic Acid Through Titration

Question 4: List the 3 errors; • Adding too many drops of NaOH at the same time would affect the results because we can’t determine the exact equivalent point when the color changed. The results won’t be accurate and that will affect all the data that are dependent on the amount of NaOH to titrate. • Other error could be the hardness to notice a color change; we always use a white paper under the flask to determine when the color changes right away. And if we don’t use the white paper it will be hard to determine the color change and the amount of NaOH that was used to titrate it. • Also other source of error could be by not rising the burette with NaOH before we fill up with it, or it maybe they were rinsing it with a lot of NaOH which could affect the data recording for NaOH amount of titration.

In the first part of the experiment, Part A, the standard solutions were prepared. As a whole, the experiment was conducted by four people, however, for Part A, the group was split in two to prepare the two different solutions. Calibrations curves were created for the standard solutions of both Red 40 and Blue 1. Each solution was treated with a serial 2-fold dilution to gain different concentrations of each solution.

This aqueous solution was then heated until all the dichloromethane evaporated off. An error could have occurred at this point in the experiment if the hot plate was too hot. If the hot plate was set above the boiling point of the ketone, the ketone could have evaporated of along with the dichloromethane. This would result in a lower percent yield of the ketone. To prevent this from happening, the hot plate should not exceed 130˚C, so no matter what ketone was isolated, it would not evaporated off.

To test for the presence of the carbonate (CO32-) anion, a small scoop of the unknown compound was mixed with

Secondly, the test tubes were not cleaned out. If there was residue from other chemicals on the test tube there could be an error in the reaction. Cleaning out the test tube before starting lab could prevent this. Finally, residue on gloves could have got into the solution. This could have caused an error in the reaction.

The water that was used in the experiment was from a pond that does not have any chemicals put into

We then slowly poured NaOH into the beaker until the solution neutralized, turning the indicator pink. The mixture would need to stay pink for 30 seconds. The paler the pink, the more accurate the measurements. We then recorded the remaining amount of NaOH in the buret. This process was repeated for the Up & Up gastric

Firstly, because the NaHCO3 compound was not stored in a sealed container, therefore dust particles could have changed the results, and making the product impure. Also, there are uncertainties associated with the instruments used in this experiment. This, if the products were measured slightly more than should be, this could have affected the concentrations of the solutions, and therefore causing a larger

The cleanliness of the apparatus used is was a possible source of error. Even after trying to find the cleanest pipets and glassware, there were a distinct hint of purple and blue that covered parts of the apparatuses. Even after cleaning with ethanol, the residue could not be fully removed from the materials, thus possibly affecting the concentration of solutions that passed through the stained apparatuses. Having a more effective cleaning method would resolve this source of error. Since the reaction between the dye and NaOH was instantaneous, it was impossible to mix the solution together and measure the absorbance of the solution from the moment of reaction.

NH3(aq) + H+(aq) ↔ NH4+(aq) 8. In step 8, NaOH was added a drop at a time to an ammonia-ammonium ion buffer. By adding NaOH to the ammonia-ammonium ion buffer caused the pH to nearly stay the same, unlike what happened in step 1 where the pH went down after HCl was added.

The equation of the reaction between sodium hydroxide and ethanoic acid is as follows: CH3COOH + NaOH → CH3COONa + H2O We can measure the end point of titration process and we can also measure the amount of reactants. The concentration of ethanoic acid in the vinegar can be determined through stoichiometric calculations, Using the values obtained from the titration, and also the chemical equation as a reference. Phenolphthalein indicator is used in this acid-base titration Equipment and materials:

Procedure A. Preparation of NaOH solution The molarity of a solution is the ratio of the number of solutes dissolved in a liter of solution. To figure out the needed mass (in grams) of NaOH pellets to be dissolved in a 0.25 L of water, remember that a mole is equivalent to the quotient of mass over the molar mass of the substance. This was used to rearrange the base formula and to derive the mathematical equation of mass in terms of molarity. mass (g) =

(Approximate pH ranges for color change: 3.1-4.4) To sum up, back titration is a effective way for the determination of Calcium Carbonate as experimental results were close to it’s true and accepted value of 20%. References Antoine.frostburg.edu, (2014). Acid-Base Indicators. [online] Available at: http://antoine.frostburg.edu/chem/senese/101/acidbase/indicators.shtml [Accessed 12 Dec.

The chemical equation for this experiment is hydrochloric acid + sodium thiosulphate + deionised water (ranging from 25ml to 0ml in 5ml intervals)  sodium chloride + deionised water (ranging from 25ml to 0ml in 5ml intervals) + sulphur dioxide + sulphur. As a scientific equation, this would be written out as, NA2S2O3 + 2HCL + H2O (ranging from 25ml to 0ml in

That caused a new initial reading of NaOH on the burette (see Table1 & 2). The drops were caused because the burette was not tightened enough at the bottom to avoid it from being hard to release the basic solution for titrating the acid. The volume of the acid used for each titration was 25ml. The volume of the solution was then calculated by subtracting the initial volume from the final volume. We then calculated the average volume at each temperature.