Lab Final Flashcards
Mathematical model for water cooling from experiment 1
Exponential decay
Nominal volume
The volume given by the measuring device. May differ from the true volume appreciably.
Mean deviation formula
(Σ|x - x̄ |)/n
Can pentane solutions be poured down the sink?
No!
How do you clean the glassware in experiment three, in which pentane and oleic acid was used?
Rinse the glassware with acetone or pentane, NEVER water!
Flow of light through a spectrophotometer
Light source –> lens –> sample cell –> slit –> diffraction grating –> diode array detector
Beer’s Law
Relates absorbance to concentration
A = (molar absorptivity)(path length)(concentration)
What temperature is a bunsen burner in its dark blue inner cone?
Extremely hot
What temperature is a bunsen burner in its pale blue violet outer region?
Moderately hot
What temperature is a bunsen burner if its flame is luminous and yellow?
Cool
Concentration (c) calculation
= (absorbtivity)(cm or unit of length) / (absorbance) = ab/A
Percent yield formula
(Experimental mass / theoretical mass) times 100
In the redox reaction involving hydrogen peroxide and permanganate, what is being oxidized?
Oxygen / hydrogen peroxide
In the redox reaction involving hydrogen peroxide and permanganate, what is being reduced?
Manganese / permanganate
In the redox reaction involving hydrogen peroxide and permanganate, what is the oxidizing agent?
The permanganate ions
In the redox reaction involving hydrogen peroxide and permanganate, what is the reducing agent?
The hydrogen peroxide
What was the purpose of the NaOH in the first part of the neutralization experiment?
The solution of unknown concentration being titrated
What was the purpose of the KHP (potassium hydrogen phthalate) in the first part of the neutralization experiment?
The standard solution of known concentration used as the titrant or reagent for the NaOH solution of unknown concentration
What was the purpose of the NaOH in the second part of the neutralization experiment?
The standard solution of known concentration used as the titrant or reagent for the vinegar solution of unknown concentration
What was the purpose of the vinegar in the second part of the neutralization experiment?
The solution of unknown concentration being titrated
What was the purpose of the phosphoric acid in the third part of the neutralization experiment?
The solution of concentration being titrated to determine how many times the acid has reacted with the titrant
What was the purpose of the NaOH in the third part of the neutralization experiment?
The standard solution of known concentration used as the titrant or reagent for the phosphoric acid solution of unknown concentration
Hess’s Law is dependent on…
The first law of thermodynamics, which states that energy cannot be created nor destroyed.
It also depends on enthalpy being a state function
How to standardize the molarity of a titrant?
Moles of analyte present / original volume of the analyte
True volume
The volume etched on the side of the volumetric glassware
What kind of powder was used to enhance the visibility of the oil layer in that one useless experiment?
Lycopodium powder
Does water density change with temperature?
Yes
Which test should be used to determine if an outlying value can be omitted from a data set?
Q Test
What transition metal was contained within the compound analyzed via absorption
spectroscopy this semester in experiment 4?
Chromium
Do all crystalline materials have the exact atom ratios predicted by their molecular formulae?
Nope
What is the endpoint of permanganate redox titration?
A pale pink color
Which law states that “If two elements combine to form more than one compound, then the
amounts of element A that combine with a fixed amount of element B will be in a ratio of
small whole numbers?
The Law of Multiple Proportions
According to Boyle’s law, as volume (V) decreases, pressure (P) increases. A graph of 1/P
on the x-axis and V on the y-axis should…
Be Linear and not regress to zero
The molar volume of what two gases were determined in the molar volume of a gas
experiment?
Hydrogen and Oxygen
A gas that has a pressure of 1.0 atm and volume of 45 mL at 25°C is heated to 78°C. If the
pressure remains constant, does the volume increase or decrease?
Increase
