Chem 126 Lab Final with correct questions
and answers 2025/2026.
The accuracy of a single measurement can be determined by comparison to a "known value."
What additional information, if any, is needed in order to state the precision of the
measurement? - correct answers multiple data points are needed to determine precision
A primitive cubic unit cell has how many atoms? - correct answers 1 atom
A primitive cubic unit cell has what coordination number? - correct answers 6
A primitive cubic unit cell has what percent occupied volume? - correct answers the least
In a primitive cubic unit cell where do the atoms touch? - correct answers along the edge length
What is the formula for a primitive cubic unit cell? - correct answers 2r=l
A face centered cubic unit cell has how many atoms? - correct answers 4 atoms
A face centered cubic unit cell has what coordination number? - correct answers 12
,A face centered cubic unit cell has what percent occupied volume? - correct answers the most
In a face centered cubic unit cell, where do the atoms touch? - correct answers along the face
diagonal
What is the formula for a face centered cubic unit cell? - correct answers 4r=l√2
A body centered cubic unit cell has how many atoms? - correct answers 2 atoms
A body centered cubic unit cell has what coordination number? - correct answers 8
A body centered cubic unit cell has what percent occupied volume? - correct answers the
middle
In a body centered cubic unit cell where do the atoms touch? - correct answers along the body
diagonal
What is the equation in a body centered cubic unit cell? - correct answers 4r=l√3
When plotting on a graph to get a straight line, what information can be derived from the
graph? - correct answers slope, y intercept
What plotting "temperature" vs. "pressure" which is on the y axis - correct answers temperature
How would a determination of the boiling point elevation constant be affected by forgetting to
account for the fact that the compound is ionic and breaks up into 3 ions per formula unit? -
correct answers the boiling point is measure and the concentration in molality is known. the kb
, is calculated from the equation ∆tb= ikbm, the true value of kb should be a third of the value of
the calculated kb if the value of i is not used
What are some sources of error possible in the colligative properties experiment? - correct
answers unknowingly losing mass of solute, measure boiling point is smaller, calculated molality
is smaller, calculated moles is smaller and thus molar mass is larger
Do you know what to graph in order to determine the order of a reaction with respect to one
substance whose concentration is changing? - correct answers so that one can determine
whether it is zero, first or second order in the following make a graph of [A] vs. time, ln[A] vs.
time and 1/[A] vs. time to identity the order
How would you drive a reaction that is endothermic and has a greater number of gaseous
reactant than gaseous products? - correct answers heat it and increase the pressure
Explain how an increase in temperature affects the equilibrium of an exothermic reaction and
explain the effect on the equilibrium constant - correct answers heating an exothermic reaction
will cause it to reach equilibrium by making more reactants and the increase in temperature
causes the equilibrium constant to decrease
Why is it possible to separate Cu2+ from Mg2+ using NH3? - correct answers both the Cu2+ and
Mg2+ react with OH- that is present in producing the blue precipitate with the Cu2+ (Cu(OH)2)
and a white precipitate with the Mg2+ (Mg(OH)2) but with the NH3 present the copper will
further react to form Cu(NH3)4+ which dissolves and thus we will have a deep blue solution
with the white Mg(OH)2 that can be centrifuged and decanted and thus separated
The following reaction is pink in cold water and blue in hot water, is the reaction exothermic or
endothermic?
Co(H2O)6 2+(pink) + 4Cl- <--> CoCl4 2- (blue) + 6H2O - correct answers in cold it is towards the
reactant side and in hot water it is towards the products side, thus it is endothermic, adding
heat causes endothermic reactions to make more products and turning blue
and answers 2025/2026.
The accuracy of a single measurement can be determined by comparison to a "known value."
What additional information, if any, is needed in order to state the precision of the
measurement? - correct answers multiple data points are needed to determine precision
A primitive cubic unit cell has how many atoms? - correct answers 1 atom
A primitive cubic unit cell has what coordination number? - correct answers 6
A primitive cubic unit cell has what percent occupied volume? - correct answers the least
In a primitive cubic unit cell where do the atoms touch? - correct answers along the edge length
What is the formula for a primitive cubic unit cell? - correct answers 2r=l
A face centered cubic unit cell has how many atoms? - correct answers 4 atoms
A face centered cubic unit cell has what coordination number? - correct answers 12
,A face centered cubic unit cell has what percent occupied volume? - correct answers the most
In a face centered cubic unit cell, where do the atoms touch? - correct answers along the face
diagonal
What is the formula for a face centered cubic unit cell? - correct answers 4r=l√2
A body centered cubic unit cell has how many atoms? - correct answers 2 atoms
A body centered cubic unit cell has what coordination number? - correct answers 8
A body centered cubic unit cell has what percent occupied volume? - correct answers the
middle
In a body centered cubic unit cell where do the atoms touch? - correct answers along the body
diagonal
What is the equation in a body centered cubic unit cell? - correct answers 4r=l√3
When plotting on a graph to get a straight line, what information can be derived from the
graph? - correct answers slope, y intercept
What plotting "temperature" vs. "pressure" which is on the y axis - correct answers temperature
How would a determination of the boiling point elevation constant be affected by forgetting to
account for the fact that the compound is ionic and breaks up into 3 ions per formula unit? -
correct answers the boiling point is measure and the concentration in molality is known. the kb
, is calculated from the equation ∆tb= ikbm, the true value of kb should be a third of the value of
the calculated kb if the value of i is not used
What are some sources of error possible in the colligative properties experiment? - correct
answers unknowingly losing mass of solute, measure boiling point is smaller, calculated molality
is smaller, calculated moles is smaller and thus molar mass is larger
Do you know what to graph in order to determine the order of a reaction with respect to one
substance whose concentration is changing? - correct answers so that one can determine
whether it is zero, first or second order in the following make a graph of [A] vs. time, ln[A] vs.
time and 1/[A] vs. time to identity the order
How would you drive a reaction that is endothermic and has a greater number of gaseous
reactant than gaseous products? - correct answers heat it and increase the pressure
Explain how an increase in temperature affects the equilibrium of an exothermic reaction and
explain the effect on the equilibrium constant - correct answers heating an exothermic reaction
will cause it to reach equilibrium by making more reactants and the increase in temperature
causes the equilibrium constant to decrease
Why is it possible to separate Cu2+ from Mg2+ using NH3? - correct answers both the Cu2+ and
Mg2+ react with OH- that is present in producing the blue precipitate with the Cu2+ (Cu(OH)2)
and a white precipitate with the Mg2+ (Mg(OH)2) but with the NH3 present the copper will
further react to form Cu(NH3)4+ which dissolves and thus we will have a deep blue solution
with the white Mg(OH)2 that can be centrifuged and decanted and thus separated
The following reaction is pink in cold water and blue in hot water, is the reaction exothermic or
endothermic?
Co(H2O)6 2+(pink) + 4Cl- <--> CoCl4 2- (blue) + 6H2O - correct answers in cold it is towards the
reactant side and in hot water it is towards the products side, thus it is endothermic, adding
heat causes endothermic reactions to make more products and turning blue
