Abstract The unknown concentration of benzoic acid used when titrated with standardized 0.1031M NaOH and the solubility was calculated at two different temperatures (20◦C and 30◦C). With the aid of the Van’t Hoff equation, the enthalpy of solution of benzoic acid at those temperatures was determined as 10.82 KJ. This compares well with the value of 10.27KJ found in the literature. Introduction Solubility is a chemical property that is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. The resulting solution is called saturated solution. For example when a sample of sodium chloride solution in water is heated the behavior of the reaction is endothermic obstructing exothermic behavior. Another relationship that can be said about solubility is that the solubility of a solid substance increases as the temperature increases. The solubility of solutes is dependent on temperature. When a solid dissolves in a liquid, it then changes its physical state (from solid to liquid) by melting. Heat is needed to break the bonds holding the molecules in the solid together and at the same time; heat is given off during the formation of new bonds between solute and solvent. Results Table1. Results for titration of benzoic acid with NaOH at 20◦C V(NaOH) ml V(C_6 …show more content…
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. It was calculated and found that the concentration of benzoic acid was higher at 30℃ (0.0308M) than at 20℃
A hot plate was placed under the ring stand. 50 mL of 3.0 M NaOH in a 250 mL beaker and a stir bar was placed in the beaker. The beaker with NaOH was placed on the hot plate and 3.75 grams of NaAlO2*5H2O was placed in the beaker. The temperature probe was placed in the beaker with the solution, not touching the bottom of the beaker. The solution was heated and stirred till the solution dissolved.
I always knew heat caused things to dissolve faster, similar to how things melt faster the higher the temperature gets above their melting point. I included an extra reactant in my second experiment because I was interested in seeing how that would affect the
During one experiment the results were, they found out that the higher the temperature of the water the faster the molecules will move and the lower the temperature the slower the molecules move. The molecules are what are make the alka-seltzer dissolve. So if they move slower the alka-seltzer dissolves slower, same as if the molecules move faster than the alka-seltzer will dissolve faster. Also according to a state science fair the results were that it took 19.53 seconds for the alka-seltzer to dissolve in hot water, 36.15 seconds for the alka-seltzer to dissolve in the warm water, and 96.17 seconds (1 minute and 36.17 seconds) for the alka-seltzer to dissolve in cold water. The alka-seltzer dropped in the cold water proved to dissolve the
As much was conducted throughout this lab, the projected completion of this lab displays that ultimately, the higher the temperature of the water, the faster the dissolving rate of the Alka-Seltzer is. In other words, the hotter the water temperature the quicker the tablet dissolves within the water in regards to the amount of time it took to dissolve. Furthermore, this experiment helps to explain that, if water is taken at a higher temperature and Alka-Seltzer is placed within the water, the Alka-Seltzer will take less time to dissolve because the higher temperatures cause the tablet to melt at a quicker rate. This compares to when Alka-Seltzer is placed in colder temperatures, where instead it takes more time to dissolve, because the lower
The purpose of this experiment was to learn about the electrophilic aromatic substitution reactions that take place on benzene, and how the presence of substituents in the ring affect the orientation of the incoming electrophile. Using acetanilide, as the starting material, glacial acetic acid, sulfuric acid, and nitric acid were mixed and stirred to produce p-nitroacetanilide. In a 125 mL Erlenmeyer flask, 3.305 g of acetanilide were allowed to mix with 5.0 mL of glacial acetic acid. This mixture was warmed in a hot plate with constantly stirring at a lukewarm temperature so as to avoid excess heating. If this happens, the mixture boils and it would be necessary to start the experiment all over again.
3. Upon adding 20 drops of NaOH, a white precipitate was formed signifying acidic impurity. In the second NaOH mixture, about 20 drops were administered and no precipitate formed indicating that the ample is more pure than before. Data: Weight of flask = 75.10 grams Weight of the flask with solids =
Solubility in Water Solubility is the property of a solute to dissolve in a solvent to form a solution. Pouring and mixing the powders in water will test their solubility. A highly soluble powder will dissolve in the water without leaving an traces of solid powder. A less soluble powder would somewhat dissolve, but remains of the powder would gather on the bottom of the container.
Temperature of the liquid will raise when the entire solid has melted. An impure solid generally melts over a range of temperatures below the melting point of the principal component. Discussion: The main application of melting is chocolate moulding.
In the experiment, the primary initial chemical used was a 2.019 g mixture of benzocaine, and benzoic acid. Furthermore, the outcome of the experiment was 0.310 g of pure benzocaine, and 0.145 g of pure benzoic acid. Therefore, the percent recovery of the benzocaine and benzoic acid compounds was found to be 15.35%, and 7.18% respectively. In addition, later on in the process the melting points of the pure compounds were measured. The data of the benzocaine received from the lab was 93.2˚C, which is extremely close to the one reserved in literature (89˚C).
Initially, the conversion of benzyl alcohol in to benzaldehyde was chosen as a model reaction to optimize the reaction conditions. Effect of reaction time and mmol of H2O2 on progress of oxidation reaction was studied (Fig. 4. the experiment was performed with 20 mg catalyst, 10 ml acetonitrile and two different amount of H2O2 1 and 2 mmol for 1mmol benzyl alcohol at reflux condition (85 ºC ) and plotted with respect to the time. With increasing the mole ratio of BzOH : H2O2 from 1:1 to 1:2, the conversion of benzyl alcohol increased from 75% to 93%. The conversion also increased with increasing time of reaction and then remain constant at 180 min.
Our last experiment involved investigating the solubility of an unknown solid. The unknown substance did not dissolve in most of the solvents with the exception of water. The solubility of the unknown substance leads me to conclude that the substance is polar, however it is as polar as water thus indicating that it is more polar than ethanol and TTE. With our noted observations, we came to the general conclusion that the solubility of a substance is determined by how similar the polarities of the solute and the solvent it is immersed in. For instance, iodine remained in its solid form in water and dissolved slightly in TTE.
Colligative Properties include how freezing temperature, boiling temperature and vapor pressure change. Most of the changes in the temperatures are due to the vapor pressure. The vapor pressure changes when a solute is dissolved into a solution. The freezing temperature of a solution would decrease in most solutions because few solutes dissolve well in solid solvents. The temperature needed to boil a solution would increase because of the equilibrium between liquid and gas phases.
Ali Atwi : Internal assesment – calculating of the concentration of ethanoic acid in vinegar AIM : To calculate the concentration of ethanoic acid CH3COOH in vinegar using stoichiometric equations, ( Yamaha brand ) Introduction : I personally like to add a little bit of vinegar on my food because it makes it taste better, yet I know that vinegar contains acid, and I also know the consequences of highly concentrated acid intake, like severe itching and stomach ache, vomiting. Venigar contains a small percentage of ethanoic acid Ch3COOH. This practical aims to find out the concentration of the of the vinegar against a standard solution of sodium hydroxide soloution of concentration 0.1 mol dm3 through acid-base titration, the label on the bottle says 6%.
Practical I: Acid-base equilibrium & pH of solutions Aims/Objectives: 1. To determine the pH range where the indicator changes colour. 2. To identify the suitable indicators for different titrations. 3.
That is, the higher the temperature of the solvent (water), the more solute (salt) that will dissolve in it. In this experiment, we will study the solubility of potassium nitrate (KNO3) in water. You will dissolve different quantities of this salt in a given amount of water at a temperature close to its boiling point. Which solution will be