CHEM 1411
Practice Lab Exam: Total 100 points.
Separation of the Components in an Inorganic Mixture
Mass of evaporating dish:
42.8 g
Mass of evaporating dish and unknown mixture:
45.6 g
Mass of unknown mixture:
_______________________ g
Mass of evaporating dish after subliming NH4Cl:
44.6 g
Mass of NH4Cl:
_______________________ g
Percent of NH4Cl:
_______________________ %
(Show calculations for percent of NH4Cl)
What does MSDS mean? This is to ask you to write out the whole words of this abbreviation.
Why you must do the first heating in the fume hood?
What chemicals are in the white fume you saw in the experiment?
What is the major error contributed to percent recovery in this experiment?
What attributes to the recovery greater than 100% in this experiment?
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The Iron-copper Molar Ratio-Single Replacement Reaction and Limiting Reagent
The quantities of chemical used, copper (II) sulfate pentahydrate and iron metal, are actually in
the stoichiometric quantities, and the data sheet of this experiment is not clear, and thus no
calculation from this experiment will be asked.
What are the color and chemical formula of copper (II) sulfate pentahydrate, respectively?
What does it mean “limiting reactant or limiting reagent”?
What is the major source of error of this experiment?
The replaced Cu metal (molar mass is about 63.55 g/mol) is not washed completely with
de-ionized and dried. If any of copper (II) sulfate pentahydrate (molar mass is about 250
g/mol) remains, the error will be huge.
Reactions in Aqueous Solutions: Single- and Double-Displacement Reactions:
Write its balanced molecular equation and net-ionic equation respectively for zinc metal and
hydrochloric acid.
Molecular:
Net-Ionic:
Write its balanced molecular equation and net-ionic equation respectively for sodium
carbonate and hydrochloric acid.
Molecular:
Net-Ionic:
Write its balanced molecular equation and net-ionic equation respectively for calcium chloride
and sodium sulfide.
Molecular:
Net-Ionic:
Write its balanced molecular equation and net-ionic equation respectively for
nickel (II) chloride and silver nitrate.
Molecular:
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Net-Ionic:
Write its balanced molecular equation and net-ionic equation respectively for hydrochloric
acid and sodium hydroxide.
Molecular:
Net-Ionic:
Write its balanced molecular equation and net-ionic equation respectively for potassium
chloride and sodium nitrate.
Molecular:
Net-Ionic:
Column Chromatography of Spinach
What kinds of pigments are there in spinach?
What does it mean eluent?
What does it mean UV-Vis spectrophotometer? This is to ask you write out the whole words of
UV-Vis.
Why you can only touch the frosted side of the cuvette or wipe the cuvette?
What does it mean “blank”?
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Molar Mass of a Volatile Liquid:
Mass of flask + cap + rubber band
45.6 g
Temperature of boiling water
98 oC
Barometric pressure
745 mm Hg
Mass of flask + rubber band + cap + condensed vapor
45.8 g
Mass of condensed liquid
________________________ g
Volume of flask
143 mL
Molar mass of vapor
____________________ g/mol
(Show calculations)
Why you need to wipe the aluminum foil inside and outside before you weight it after heating?
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