The pH recorded by using pH electrode before adding NaOH. The solution titrated by 2 ml of NaOH each time and the pH recorded until the color change. These steps were done for the two known solutions and the unknown solution. Part 2 10 ml of vinegar placed in 100ml volumetric flask and deionized water added until the mark. The solution transferred in 150 ml beaker labeled as beaker #1.
The normality of the unknown base is calculated after the solution has reached the end point. The amount of substance being delivered is calculated in units of equivalents per litre using the formula: VaNa = VbNb Experimental In order to titrate the acid with the unknown base, a solution of the acid was prepared. 5.1722 (±10%)g of potassium hydrogen phthalate acid is obtained using a weighing boat and transferred into a volumetric flask containing 250mL of boiled distilled water. Volumetric flask was shaken several times in order to assist the powder to dissolve. Once dissolved, 24.9734 (± 0.0045)mL of acid was pipetted into an Erlenmeyer flask along with 25mL of cool (recently boiled) distilled water.
A flame test was then conducted and the identity of the cation was determined. To determine the anion, the anion had to be separated first from the cation in the unknown compound. To do this, 0.1 grams of the unknown compound and 0.5 grams of sodium carbonate had to be boiled in 5 mL of distilled water. Once the solution boiled for 10 minutes, the precipitate was centrifuged out and the anion solution was left. 0.1 M silver nitrate was added to the anion solution and a precipitate was formed.
Observation 7 Hydrogen Gas was being performed. Observation 8 Zinc Chloride White bubbles started, and still has solid. Discussion: During the experiment we had to pour into the test tube 5 ML of Copper Sulfate Solution. Once this was done it started turning into a blue green color. Next, Zinc and Copper Sulfate combined which there was gas bubbles and the color changed into blue green color.
Abstract: The effect of temperature on solubility of potassium nitrate was demonstrated. This was done by dissolving the salt in distilled water at different concentrations and finding the temperature at which crystallisation occurred. From this a solubility curve could be formed. It was found that as the temperature increased, so did the solubility of potassium nitrate in distilled water. At 50C our results indicated a solubility of 89 g/100mL of H2O which was close to the known solubility of 80 g/100mL.
The precipitate was the combination of lead nitrate + potassium chromate + the mixture of the two + lead chromate; or Pb(NO3)2 + K2CrO4 --> 2 KNO3 + PbCrO4 (I learned the above from the iLab overview and ChemLab introduction) Procedure Step 1: I added 50 ml of potassium chromate to 1M solution in a 100 ml beaker. Step 2: The beaker was half way filled with a white solution, the potassium chromate Step 3: I added 50 ml of lead nitrate to the same beaker Step 4: The volume of the fluid inside the beaker increased and the solution became dotted and formed a precipitate on the bottom of my beaker, indication a chemical reaction occured. Step 5: I filtered my precipitate into a 250 ml Erlenmeyer flask using a Buchner funnel Step 6: The white liquid on the bottom of my flask indicated that I filtered the solution Step 7: I got a weight of my precipitate by placing it inside a test tube Step 8: The weight of my precipitate is 16.160 grams Observations and Results Describe appearance of precipitate (did it exhibit any color? ): My precipitate is yellow in color Weight of filtered precipitate: 16.160 grams Discussion The precipitate formed was lead chromate, or PbCrO4 resulting from the mixture of potassium chromate and lead nitrate. The experiment was done to get a precipitate from the two reactant
.40g of NaH_2PO_4, and .40g of Na_2HPO_4 was measured into a 150 mL beaker. 50mL of distilled water was then measured in to a graduated cylinder and added to the 150ml solution of NaH_2PO_4 and Na_2HPO_4. 20 drops of the .04% Bromothymol blue solution was then also added to the buffer solution. After adding the 20 drops the tint of the liquid changed to a light green. The Vernier pH probe was calibrated and used to determine the pH of the phosphate buffer solution which was 6.81.
Determination of Enthalpy Change Objective: to find the enthalpy change (∆H) in the decomposition of Sodium Hydrogen Carbonate. Materials: Calorimeter, 2.00 mol HCl, NaHCO3, Na2CO3, Lab Quest, Temperature Probe, Graduated cylinder, Balance scale. Procedure | Observations | 1. Obtain 50 mL of HCl in a beaker. | N/A | 2.
The temperature was raised to 70 degrees Celsius and 4.419 g of salicylic acid was measured out on a balance and transferred into a 125. mL Erlenmeyer flask. Next, 8.00 mL of acetic anhydride was measured out and poured into the flask containing salicylic acid, ten drops of phosphoric acid was placed inside. The flask was then immersed into the hot water bath for twenty minutes. A vacuum filtration system was set up and the contents of the flask was transferred onto the filter paper. The mass of the filter paper and watch glass was 42.7131 grams.