Transcript Synthesis of Potassium Dioxalatocuprate Dihydrate Lab 5 Purpose This lab will help further your understanding of stoichiometric relationships between reactants and products of chemical reactions.

Synthesis of Potassium
Dioxalatocuprate
Dihydrate
Lab 5
Purpose
This lab will help further your 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
O Stoichiometry is the study of mass relationships in a
chemical reaction.
O The law of definite proportions states that compounds
or elements react chemically to form a new compound
in definite proportions.
O Before any attempt at calculations are made, reactions
have to be balanced first. Only then can we obey the
law of definite proportions.
O The limiting reagent is the reactant that runs out first in
a chemical reaction.
Reaction
O Add two water soluble compounds together
to form an insoluble solid that precipitates
out.
O Filter out all excess water soluble reagent.
O Isolate the precipitate on filter paper utilizing
three rinse compounds (water, ethanol,
acetone) and vacuum filtration.
O Determine the percent yield recovered.
Equipment Setup
Equipment Setup
Reaction
Reagents
Products

1CuSO45H2O (aq)+ 2K2C2O4H2O(aq)  1K2[Cu(C2O4)2]2H2O(s)+
5H2O + 1K2SO4(aq)
copper
sulfate
pentahydrate
potassium
oxalate
monohydrate
potassium
dioxalatocuprate
dihydrate
potassium
sulfate
Materials and Precautions
Balance function
O
O
O
O
Hotplate function
O
O
Don’t burn yourself!
Ice bath preparation
O
O
O
Weighing paper
Scoopula and contamination
Cleanup
Use more ice than water.
Location of the filter paper, chilled distilled
water, ethanol, and acetone
Waste
O
O
O
O
O
Excess or spilled potassium oxalate monohydrate should
be disposed in the oxalate solid waste container in the
fume hood.
Excess or spilled copper sulfate pentahydrate should be
disposed in the copper solid waste container in the fume
hood.
Filtrate should be disposed in the filtrate waste container
in the fume hood.
Dry product should be disposed in the copper solid waste
container in the fume hood.
After all product is scraped off, filter paper should be
placed in the filter paper waste container in the fume
hood.
Safety Concerns
O Reagents:
O
O
O
O
Acetone
Copper Sulfate Pentahydrate
Denatured Alcohol
Potassium Oxalate Monohydrate (Teratogen)
O Eye Contact:
O Stinging, tearing, redness, pain, irritation, tissue burns, conjunctivitis,
ulceration, clouding of cornea, and blurred vision
O Skin Contact:
O Defatting, dehydration, irritation, redness, pain, drying, flaking, cracking,
itching, and severe burns
O Inhalation:
O 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.
O Ingestion:
O Abdominal pain, nausea, vomiting, headaches, gastritis, gastrointestitis,
intoxication, blindness, and death. Aspiration into the lungs can cause severe
lung damage.
Lab 6 Reminder
O If you have not started on the pre-labs for Lab 6 yet, start
as soon as possible.
O Read the lab write-up in your manual (pp 149 - 174).
O Complete the pre-lab questions (pp. 149 - 174) 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.
O 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
O Review the graduated glassware, safety, and
calibration question sections.
O Remember your goggles, lab manual, and
Lab 5 Report.
O Study for the next quiz.