Pharm 121 laboratory Answer Sheets 2023/2024 (100%Verified) - Saint Louis University.

Pharm 121 laboratory Answer Sheets 2023/2024 (100%Verified) - Saint Louis University. Pharm 121 laboratory Answer Sheets. Activity 1.1. Identify the following apparatuses used in the chemistry laboratory. Write your answers on the space provided before each item. _____________________________ a. It is used to hold solids while they are being weighed or to cover a beaker. _____________________________ b. It is convenient for collecting a precipitate directly within the vessel in which it is to be dried then weighed. _____________________________ c. It is a hand-held flexible natural-rubber or plastic scraper, commonly used to transfer residues or precipitate. _____________________________ d. It is used to measure a precise volume of a liquid. _____________________________ e. It is used to transfer liquids or fine-grained materials into containers with small openings. _____________________________ f. It is an apparatus with a narrow neck used to hold and facilitate mixing without spilling. _____________________________ g. It is a squeeze bottle with a nozzle, used to rinse laboratory glassware. _____________________________ h. It is used in quantitative chemical analysis to measure the volume of a liquid or a gas. _____________________________ i. It is a multi- purpose piece of equipment used for containing a chemical reaction and measuring liquids. _____________________________ j. It is used for holding chemicals during heating to very high temperatures. _____________________________ k. It is Used your answer in “letter j”. _____________________________ l. It is used for precise dilutions and preparation of standard solutions. _____________________________ m. It is used to hold or clamp laboratory glassware and other equipment in place. _____________________________ n. It is a small bowl with a spout, used to heat and convert dilute to concentrated liquids, or liquid to gas. _____________________________ o. It is a glass instrument used to transfer a specific measured amount of liquid material from one container to another. Pharm 121 laboratory Answer Sheets. Saint Louis University – Department of Pharmacy Pharm 121 Laboratory| 4 Activity 1.2. It’s your turn! This time, you will be tasked to standardize a basic solution. Use the previous example as your guide. Complete the experiment on the activity sheet attached at the end of this term. Preparation and Standardization of 1 N Sodium Hydroxide I. Procedure: Preparation (prepare whole of the formulation) 1. Dissolve 45 grams of sodium hydroxide in about 950 milliliters of water. 2. Add a freshly prepared saturated solution of barium hydroxide until no more precipitate forms. 3. Shake the mixture thoroughly and allow to stand overnight in a stoppered bottle. 4. Decant the clear liquid or filter the solution. 5. Store in a reagent bottle Standardization (prepare 1/5 of the formulation, perform three trials) 1. Weigh accurately about 5 grams of potassium biphthalate (KHC8H4O4), previously crushed lightly and dried at 120 0C for 2 hours. 2. Dissolve it in 75 milliliters of carbon dioxide-free water. 3. Add 2-3 drops of phenolphthalein TS. 4. Titrate with the sodium hydroxide solution to the production of a permanent pink color. 5. Record the data of the first trial, then conduct two more trials. 6. Calculate the normality for each trial, then the average normality. II. Data and Results: Titer value: _______________________________________________________________________________ III. Computations IV. Chemical Reaction/s: V. Conclusion T1 T2 T3 Analyte (Potassium biphthalate) Titrant (Sodium hydroxide) 4.4 ml 4.8 ml 5 ml Computed Normality Average Normality Saint Louis University – Department of Pharmacy Pharm 121 Laboratory| 5 Activity 1.3. Show complete solution to fill in the unknown in the table below. Complete the experiment on the activity sheet attached at the end of this term. Tip: it’s important to identify which is the titrant and analyte first before solving. DATA T1 T2 T3 Hydrochloric acid 28.4 mL 31.7 mL Sodium carbonate 1.56 g 1.49 g Normality 0.985 N 0.971 N Average Normality I. Principle II. Data and Results DATA T1 T2 T3 Hydrochloric acid 28.4 mL 31.7 mL Sodium carbonate 1.56 g 1.49 g Normality 0.985 N 0.971 N Average Normality III. Computations IV. Chemical Reaction/s: V. Conclusion Saint Louis University – Department of Pharmacy Pharm 121 Laboratory| 6 Activity 2.1. Can you recall examples of weak and strong acids, as well as bases? Identify and list three of each weak and strong acid, and weak and strong bases from the pool of chemicals: Strong acid Weak acid Strong base Weak base __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ Activity 2.4. Show complete solution: If a 1.32 g sample of magnesium oxide (98.9%) were treated with 50 mL of 1.07 N sulfuric acid, what volume of 1.13 N sodium hydroxide would be required in the back titration?