ALEKS Exam Review Question with 100%
Verified Answers
Calculating Mass Concentrations
A chemist prepares a solution of potassium permanganate
KMnO4
by weighing out
21.2g
of potassium permanganate into a
400.mL
volumetric flask and filling the flask to the mark with water.
Calculate the concentration in
/gdL
of the chemist's potassium permanganate solution. Be sure your answer has the correct
number of significant digits.
C=m/V
V=400.mL * 1dL/10^2mL =4.00dL
c=21.2g/4.00dL=
5.30g/dL
Solving Applied Mass Concentration Problems
GenAlex Medical, a leading manufacturer of medical laboratory equipment, is
designing a new automated system that can detect normal levels of dissolved creatine (
0.6
,to
1.2/mgdL
), using a blood sample that is as small as
12.μL
.
Calculate the minimum mass in milligrams of creatine that the new system must be able
to detect.
Be sure your answer has the correct number of significant digits.
m=c*V
V=12uL10^-6L/1uL1dL/10^-1L=0.00012dL
m=0.6mg/dL*0.00012dL=0.0000720mg
7*10^-5mg
Analyzing a Galvanic Cell
A galvanic cell is powered by the following redox reaction:
2Cu2+
(aq) + H2(g) + 2OH−(aq)→ 2Cu+(aq) + 2H2O(l)
Answer the following questions about this cell. If you need any electrochemical data, be
sure you get it from the ALEKS Data tab.
Write a balanced equation for the half-reaction that takes place at the cathode.
Write a balanced equation for the half-reaction that takes place at the anode.
Calculate the cell voltage under standard conditions.
Round your answer to
,2
decimal places.
R: Cu^2+(aq)+e^-=Cu^+(aq)
O: H2(g)+2OH^-(aq)=2H2O(l)+2e^-
Reduction always takes place at the cathode
Oxidation always takes place at the anode
E=Ered(cathode)-Ered(anode)
+0.153V-(-0.828V)=0.98V
Suppose the galvanic cell sketched below is powered by the following reaction:
Sn
(s)+PdSO4(aq)→ SnSO4(aq)+Pd(s)
Write a balanced equation for the half-reaction that happens at the cathode of this cell.
Write a balanced equation for the half-reaction that happens at the anode of this cell.
Of what substance is E1 made? Of what substance is E2 made? What are the chemical
species in solution S1? What are the chemical species in solution S2?
A chemist designs a galvanic cell that uses these two half-reactions:
half-reactionstandard reduction potentialZn2+(aq)+2e−→
Zn(s)=E0red−0.763VNO−3(aq)+4H+(aq)+3e−→ NO(g)+2H2O(l)=E0red+0.96V
Answer the following questions about this cell.
, Write a balanced equation for the half-reaction that happens at the cathode.Write a
balanced equation for the half-reaction that happens at the anode.Write a balanced
equation for the overall reaction that powers the cell. Be sure the reaction is
spontaneous as written.Do you have enough information to calculate the cell voltage
under standard conditions?YesNoIf you said it was possible to calculate the cell voltage,
do so and enter your answer here. Be sure your answer has the correct number of
significant digits.
O:Zn^2+(aq)+2e^-=Zn(s)
R:NO3^-(aq)+4H^+(aq)+3e^-=NO(g)+2H2O(l)
Overall: 3Zn(s)+2NO3^-(aq)+8H^+(aq)=3Zn^2+(aq)+2NO(g)+4H2O(l)
(-0.763V)-(0.96V)=-1.72V
A chemist designs a galvanic cell that uses these two half-reactions:
half-reactionstandard reduction potentialMnO−4(aq)+2H2O(l)+3e−→
MnO2(s)+4OH−(aq)=E0red+0.59VCl2(g)+2e−→ 2Cl−(aq)=E0red+1.359V
Answer the following questions about this cell.
A chemist fills a reaction vessel with 0.914 atm nitrogen N2 gas, 3.80 atm oxygen O2 gas,
and 9.34 atm nitrogen monoxide NO gas at a temperature of 25.0°C.
Under these conditions, calculate the reaction free energy
ΔG
for the following chemical reaction:
+N2gO2g
Verified Answers
Calculating Mass Concentrations
A chemist prepares a solution of potassium permanganate
KMnO4
by weighing out
21.2g
of potassium permanganate into a
400.mL
volumetric flask and filling the flask to the mark with water.
Calculate the concentration in
/gdL
of the chemist's potassium permanganate solution. Be sure your answer has the correct
number of significant digits.
C=m/V
V=400.mL * 1dL/10^2mL =4.00dL
c=21.2g/4.00dL=
5.30g/dL
Solving Applied Mass Concentration Problems
GenAlex Medical, a leading manufacturer of medical laboratory equipment, is
designing a new automated system that can detect normal levels of dissolved creatine (
0.6
,to
1.2/mgdL
), using a blood sample that is as small as
12.μL
.
Calculate the minimum mass in milligrams of creatine that the new system must be able
to detect.
Be sure your answer has the correct number of significant digits.
m=c*V
V=12uL10^-6L/1uL1dL/10^-1L=0.00012dL
m=0.6mg/dL*0.00012dL=0.0000720mg
7*10^-5mg
Analyzing a Galvanic Cell
A galvanic cell is powered by the following redox reaction:
2Cu2+
(aq) + H2(g) + 2OH−(aq)→ 2Cu+(aq) + 2H2O(l)
Answer the following questions about this cell. If you need any electrochemical data, be
sure you get it from the ALEKS Data tab.
Write a balanced equation for the half-reaction that takes place at the cathode.
Write a balanced equation for the half-reaction that takes place at the anode.
Calculate the cell voltage under standard conditions.
Round your answer to
,2
decimal places.
R: Cu^2+(aq)+e^-=Cu^+(aq)
O: H2(g)+2OH^-(aq)=2H2O(l)+2e^-
Reduction always takes place at the cathode
Oxidation always takes place at the anode
E=Ered(cathode)-Ered(anode)
+0.153V-(-0.828V)=0.98V
Suppose the galvanic cell sketched below is powered by the following reaction:
Sn
(s)+PdSO4(aq)→ SnSO4(aq)+Pd(s)
Write a balanced equation for the half-reaction that happens at the cathode of this cell.
Write a balanced equation for the half-reaction that happens at the anode of this cell.
Of what substance is E1 made? Of what substance is E2 made? What are the chemical
species in solution S1? What are the chemical species in solution S2?
A chemist designs a galvanic cell that uses these two half-reactions:
half-reactionstandard reduction potentialZn2+(aq)+2e−→
Zn(s)=E0red−0.763VNO−3(aq)+4H+(aq)+3e−→ NO(g)+2H2O(l)=E0red+0.96V
Answer the following questions about this cell.
, Write a balanced equation for the half-reaction that happens at the cathode.Write a
balanced equation for the half-reaction that happens at the anode.Write a balanced
equation for the overall reaction that powers the cell. Be sure the reaction is
spontaneous as written.Do you have enough information to calculate the cell voltage
under standard conditions?YesNoIf you said it was possible to calculate the cell voltage,
do so and enter your answer here. Be sure your answer has the correct number of
significant digits.
O:Zn^2+(aq)+2e^-=Zn(s)
R:NO3^-(aq)+4H^+(aq)+3e^-=NO(g)+2H2O(l)
Overall: 3Zn(s)+2NO3^-(aq)+8H^+(aq)=3Zn^2+(aq)+2NO(g)+4H2O(l)
(-0.763V)-(0.96V)=-1.72V
A chemist designs a galvanic cell that uses these two half-reactions:
half-reactionstandard reduction potentialMnO−4(aq)+2H2O(l)+3e−→
MnO2(s)+4OH−(aq)=E0red+0.59VCl2(g)+2e−→ 2Cl−(aq)=E0red+1.359V
Answer the following questions about this cell.
A chemist fills a reaction vessel with 0.914 atm nitrogen N2 gas, 3.80 atm oxygen O2 gas,
and 9.34 atm nitrogen monoxide NO gas at a temperature of 25.0°C.
Under these conditions, calculate the reaction free energy
ΔG
for the following chemical reaction:
+N2gO2g
