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.
First, we had to calculate how many grams of copper (II) sulfate we needed to form 100 mL of a 0.200 M solution of copper (II) sulfate. We determined that we needed to use 4.994g of copper (II) sulfate to make the solution. We added distilled water to the 4.994g of copper (II) sulfate in a beaker until it reached 100 mL. Then we put the beaker on a hot plate and added a magnetic stirrer. We determined that the mass of zinc necessary to completely react with the copper (II) ions in the solution was 1.308g.
c Use the syringe to place 2 cm3 of amylase into the test tube. d Add 1 cm3 of buffer solution to the test tube using a syringe. e Use another syringe to add 2 cm3 of starch to the amylase/ buffer solution. Start the stop clock and leave it on throughout the test. Mix using a plastic pipette.
25 ml of diluted unknown acid solution to 100ml beaker by using 25 volumetric pipet. 10ml of deionized water and 3 drops of phenlpthalin indicator the beaker labeled as 3. Potentiometric titration acid solutions 125 ml of NaOH was obtaining in a beaker and 50 ml of NaOH transfer to buret the tip and the meniscus is at below 0 ml. one magnetic stirring bar placed in a beaker contain one of the known solution on a stir. The pH recorded by using pH electrode before adding NaOH.
About 125 mL of standard HCl with a molarity of 0.3125 and was poured into a buret. An unknown sample of soda ash was obtained, and for each trial, a little over 1 g of the soda ash was quantitatively transferred into a wide mouth Erlenmeyer flask. About 75 mL of DI water and 5 drops of methyl purple indicator was then added to the soda ash powder. The solution was titrated once until the solution turned light purple, and then the flask was put on the hotplate for about 3 minutes of gentle boiling. After, the solution was titrated once more in order to reach the endpoint that was indicated by a bullfrog green color.
Once the solution of sodium thiosulfate had been standardized the molarity of the solution was known and sodium thiosulfate could be used to titrate tap water and an iodine solution to determine the amount of chlorine in the tap water and iodine in the iodine solution. Procedure/ Observations: The first step of the experiment was to standardize the sodium thiosulfate solution. This was done by cleaning a 50 mL buret and rinsing it three times with sodium thiosulfate solution to ensure the surface of the buret was consistent with the sodium thiosulfate throughout. The buret was then filled with the sodium thiosulfate solution. The buret was monitored to ensure that the solution extended to the tip of the buret and that no air bubbles were present because both would cause an inaccurate titration.
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.
Procedure: 1. Fill up a beaker with 25ml water 2. Pour water into Calorimeter (we had 35 ml) 3. Put in 2 grams of NaCl 4. Close the top 5.
Is There a Change in Temperature when an Alkali Neutralizes an Acid? Aim The aim of the experiment was to find out if there was a change in temperature when we added an alkali (Sodium Hydroxide) to an acid (Hydrochloric Acid) to neutralize it. Hypothesis We hypothesized that there was going be a raise in temperature as we add 1ml of Sodium Hydroxide at a time to the Hydrochloric Acid due to the neutralization of the acid. The neutralization is chemical reaction that causes an exothermic reaction. Sodium Hydroxide + Hydrochloric Acid Sodium Chloride + Water NaOH(aq) + HClaq → NaCl(aq) + H2O(l) Variables Independent The independent variable of the experiment was the amount of sodium hydroxide that we added to the acid.
Lab #3/Limiting Reagents Abstract The purpose of this laboratory experiment was to determine whether an unknown compound was sodium carbonate or sodium hydrogen carbonate by reacting a sample of it with hydrochloric acid and comparing the resulting yield of NaCl to the calculated values. The mass of an evaporating dish was taken at the start of the experiment. Then the unknown carbonate A was added in the amount of approximately one gram. The dish was weighed once more to find the definite mass of the unknown carbonate. Then, by means of a dropper bottle and stirring rod, hydrochloric acid was added until all of the unknown carbonate appeared to have reacted.