Synthesis of Potassium Dioxalatocuprate Dihydrate Lab 5

Outline Purpose Definitions Today’s Experiment Today’s Reaction Safety Concerns Precautions and Waste Equipment Setup Next Assignment

Purpose This lab will help you gain an understanding of stoichiometric relationships between reactants and products of chemical reactions. This includes an understanding of concepts such as limiting reagents, yields, and percent error.

Definitions Stoichiometry is the study of mass relationships in a chemical reaction. The law of definite proportions states that compounds or elements react chemically to form a new compound in definite proportions. Before any attempt at calculations are made, reactions have to be balanced first. Only then can we obey the law of definite proportions. The limiting reagent is the reactant that runs out first in a chemical reaction.

Reaction Add two water soluble compounds together to form an insoluble solid that precipitates out. Filter out all excess water soluble reagent. Isolate the precipitate on filter paper with the help of three rinses. Determine the percent yield recovered.

Reaction Reagents Products 1CuSO45H2O (aq)+ 2K2C2O4H2O(aq) 1K2[Cu(C2O4)2]2H2O(s)+ 5H2O + 1K2SO4(aq) copper potassium potassium potassium sulfate oxalate dioxalatocuprate sulfate pentahydrate monohydrate dihydrate

Precautions and Waste Filtrate should be disposed in the wet copper waste container only. Dry product and waste copper sulfate should be disposed in the dry copper waste container only. After all product is scraped off, filter paper should be placed in the filter paper waste container. Cleaning and maintaining balances…

Equipment Balance function (using weighing paper) Hotplate function Ice bath preparation Where to find filter paper

Equipment Setup

Equipment Setup

Safety Concerns Reagents: Eye Contact: Skin Contact: Inhalation: Acetone Cupric Sulfate Denatured Alcohol Potassium Oxalate Eye Contact: Stinging, tearing, redness, pain, irritation, tissue burns, conjunctivitis, ulceration, clouding of cornea, and blurred vision Skin Contact: Defatting, dehydration, irritation, redness, pain, drying, flaking, cracking, itching, and severe burns Inhalation: Irritation, ulceration, and perforation of the respiratory tract, coughing, sore throat, shortness of breath, dizziness, dullness, drowsiness, loss of appetite, inability to concentrate, headache, nervousness, cramps, CNS depression, narcosis, and unconsciousness. Fumes from heating may cause symptoms similar to a cold. Ingestion: Abdominal pain, nausea, vomiting, headaches, gastritis, gastrointestitis, intoxication, blindness, and death. Aspiration into the lungs can cause severe lung damage.

Lab 6 Reminder If you have not started on the pre-labs for Lab 6 yet, start as soon as possible. Read the lab write-up in your manual (pp 153 - 178). Complete the pre-lab questions (pp. 155 - 178) in MicroLab™ in the SCICom lab (NSB 204), Chemistry Resource Center (CPSB 302K) or on your personal computer if you download the program. The program may be downloaded from http://www.microlabinfo.com under the Downloads link. Take this exercise seriously. You will be required to complete a similar exercise in lab next week without help from your lab manual.

Skill Evaluations Review the graduated glassware, safety, and calibration question sections. Remember your goggles, lab manual, and Lab 5 Report. Prepare for the quiz.