CHEM 162 LAB #6 SYNTHESIS OF ASPIRIN
COMPLETE SOLUTION FINAL PAPER 2026
COMPLETE QUESTIONS WITH CORRECT
ANSWERS GRADED A+
⩥ This question counts the weight of two questions. The half-life of a
reactant in a first-order reaction was measured to be 6.10 hours. If the
starting concentration is 1.00 M, what is the remaining concentration
after 7.43 hours?
The first-order rate equations are
ln [A]t = -kt + ln [A]0 and t1/2=0.693/k
Calculate k, the rate constant and select the correct units for k (leave one
extra significant figure to prevent rounding error).
Calculate the remaining concentration after 7.43 hours. Answer:
k=0.01136 1/hr
0.430 M
⩥ Adding 17.5 g of an unknown compound to 100.0 g of water results in
a freezing point lowering of -1.80 °C. Calculate the molality and molar
mass of the unknown compound. You may assume that the density of
water is 1.00 g/mL, and Kf for water is 1.86 °C/m.
,Equation: ΔTf = Kf m. Answer: 0.9677m
1.81 g/mol
⩥ Select the correct expression for the rate of the following reaction, in
terms of the concentrations of reactants and products.
2 H2O2 → 2 H2O + O2. Answer: rate= -1/2[H2O2]/d. t
=1/2[h2o]/d.t
=1/1[o2]/d. t
⩥ the definition of molality (m) is
a. mol solute per liter of solution
b. none
c. mol solute per liter of solvent
d. mol solute per kilogram of solution
e. mol solute per kilogram of solvent. Answer: e.
⩥ the rate law for a second-order reaction is written. Answer:
rate=k[A]^2
⩥ You would expect a molecule of the formula C8H18 to be most
soluble in
a. C6H6
b. none
,c. H2O
d. CH3OH
e. NH3. Answer: a.
⩥ gases are most soluble in water at
a. high temps and low pressures
b. high temps and high pressures
c. low temps and low pressures
d. low temps and high pressures. Answer: d.
⩥ If a nonvolatile solute is added to a solvent, you would expect the
mixture to show
a. Freezing point depression and boiling point elevation
b. Freezing point elevation and boiling point depression
c. None of these. Answer: a.
⩥ If you are given the rate constant of a reaction at four different
temperatures, how would you calculate the activation energy from the
equation
ln k= -Ea/RT+ln A
plot what as x?
plot what as why?
activation energy calculated from?. Answer: x: 1/T
, y: ln k
Ea: slope=-Ea/R
⩥ In the energy diagram below, the activation energy of the forward
reaction is shown by which arrow?. Answer: bottom of curve to top of
curve
⩥ If a solution contains 30. ppm (parts per million) of a pollutant, what
percentage is this?
a. 3.0 x 10-4 percent
b. 0.30 percent
c. None of these
d. 3.0 x 10-5 percent
e. 0.0030 percent. Answer: e.
⩥ The effect of a catalyst on the activation energy of a reaction is to
a. Lower the activation energy
b. Raise the activation energy
c. None of these. Answer: a.
⩥ An elementary reaction is a reaction that occurs in a single step..
Answer: T
COMPLETE SOLUTION FINAL PAPER 2026
COMPLETE QUESTIONS WITH CORRECT
ANSWERS GRADED A+
⩥ This question counts the weight of two questions. The half-life of a
reactant in a first-order reaction was measured to be 6.10 hours. If the
starting concentration is 1.00 M, what is the remaining concentration
after 7.43 hours?
The first-order rate equations are
ln [A]t = -kt + ln [A]0 and t1/2=0.693/k
Calculate k, the rate constant and select the correct units for k (leave one
extra significant figure to prevent rounding error).
Calculate the remaining concentration after 7.43 hours. Answer:
k=0.01136 1/hr
0.430 M
⩥ Adding 17.5 g of an unknown compound to 100.0 g of water results in
a freezing point lowering of -1.80 °C. Calculate the molality and molar
mass of the unknown compound. You may assume that the density of
water is 1.00 g/mL, and Kf for water is 1.86 °C/m.
,Equation: ΔTf = Kf m. Answer: 0.9677m
1.81 g/mol
⩥ Select the correct expression for the rate of the following reaction, in
terms of the concentrations of reactants and products.
2 H2O2 → 2 H2O + O2. Answer: rate= -1/2[H2O2]/d. t
=1/2[h2o]/d.t
=1/1[o2]/d. t
⩥ the definition of molality (m) is
a. mol solute per liter of solution
b. none
c. mol solute per liter of solvent
d. mol solute per kilogram of solution
e. mol solute per kilogram of solvent. Answer: e.
⩥ the rate law for a second-order reaction is written. Answer:
rate=k[A]^2
⩥ You would expect a molecule of the formula C8H18 to be most
soluble in
a. C6H6
b. none
,c. H2O
d. CH3OH
e. NH3. Answer: a.
⩥ gases are most soluble in water at
a. high temps and low pressures
b. high temps and high pressures
c. low temps and low pressures
d. low temps and high pressures. Answer: d.
⩥ If a nonvolatile solute is added to a solvent, you would expect the
mixture to show
a. Freezing point depression and boiling point elevation
b. Freezing point elevation and boiling point depression
c. None of these. Answer: a.
⩥ If you are given the rate constant of a reaction at four different
temperatures, how would you calculate the activation energy from the
equation
ln k= -Ea/RT+ln A
plot what as x?
plot what as why?
activation energy calculated from?. Answer: x: 1/T
, y: ln k
Ea: slope=-Ea/R
⩥ In the energy diagram below, the activation energy of the forward
reaction is shown by which arrow?. Answer: bottom of curve to top of
curve
⩥ If a solution contains 30. ppm (parts per million) of a pollutant, what
percentage is this?
a. 3.0 x 10-4 percent
b. 0.30 percent
c. None of these
d. 3.0 x 10-5 percent
e. 0.0030 percent. Answer: e.
⩥ The effect of a catalyst on the activation energy of a reaction is to
a. Lower the activation energy
b. Raise the activation energy
c. None of these. Answer: a.
⩥ An elementary reaction is a reaction that occurs in a single step..
Answer: T
