Transcript Synthesis of Potassium Dioxalatocuprate Dihydrate Lab 7 Purpose This lab will help further your understanding of stoichiometric relationships between reactants and products of chemical reactions.

Synthesis of Potassium
Dioxalatocuprate Dihydrate
Lab 7
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

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 reagent 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
utilizing three rinse compounds (water,
ethanol, acetone) and vacuum filtration.
Determine the percent yield recovered.
Equipment Setup
Equipment Setup
Filtering flask
Reaction
Reagents
Products
A
B
C

1CuSO45H2O(aq)+2K2C2O4H2O(aq) 
1K2[Cu(C2O4)2]2H2O(s)+
D
E
5H2O + 1K2SO4(aq)
copper
sulfate
pentahydrate
potassium oxalate
monohydrate
potassium
dioxalatocuprate
dihydrate
potassium
sulfate
Calculations
mass A
Moles of A =
fw A
mass B
Moles of B =
fw B
2 m ol B
Limiting Reagent (LR) Ratio =
1 mol A
Moles of CLR
stoichiometric moles C
= (moles of LR) x
stoichiometric moles LR
Theoretical Yield = (moles of C) x (fw of C)
% Yield =
actual yield,g
x 100%
theoretical yield,g
Materials and Precautions
Balance function




Hotplate function


Don’t burn yourself!
Ice bath preparation



Weighing paper
Scoopula and contamination
Cleanup
Use more ice than water.
Location of the filter paper, chilled distilled water,
ethanol, and acetone
Waste





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

Reagents:





Eye Contact:


Defatting, dehydration, irritation, redness, pain, drying, flaking,
cracking, itching, and severe burns
Inhalation:


Stinging, tearing, redness, pain, irritation, tissue burns, conjunctivitis,
ulceration, clouding of cornea, and blurred vision
Skin Contact:


Acetone
Copper Sulfate Pentahydrate
Denatured Alcohol
Potassium Oxalate Monohydrate (Teratogen)
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.
Next Week: Lab 8 Reminder



Read the required reading
material from your textbook
and lab manual.
Complete your pre-lab
questions.
Submit your Lab 7 Report.