CH18 - Mastering Chemistry - Alaa Hashim

In the process of oxidizing I− to I2, SO42− is reduced to SO2. How many moles of SO2 are produced in the formation of one mole of I2? Express your answer numerically in moles.

1 mol

Part complete Balance the following equation: K2CrO4+Na2SO3+HCl→KCl+Na2SO4+CrCl3+H2O Generally coefficients of 1 are omitted from balanced chemical equations. When entering your answer, include coefficients of 1 as required for grading purposes. Enter the coefficients for each compound, separated by commas, in the order in which they appear in the equation (e.g., 1,2,3,4,5,6,7).

2,3,10,4,3,2,5 The balanced reaction will be 2K2CrO4+3Na2SO3+10HCl→4KCl+3Na2SO4+2CrCl3+5H2O

#3) - Part B What are the coefficients of the reactants and products in the balanced equation above? Remember to include H2O(l) and OH−(aq) in the blanks where appropriate. Your answer should have six terms. Enter the equation coefficients in order separated by commas (e.g., 2,2,1,4,4,3). Include coefficients of 1, as required, for grading purposes.

2,6,4,2,3,8

Cathodic protection of iron involves using another more reactive metal as a sacrificial anode. Classify each of the following metals by whether they would or would not act as a sacrificial anode to iron. Drag each item to the appropriate bin. - Will not act as sacrificial anode for iron

Ag Au Sn Pb Cu

Part complete What element is being oxidized in the following redox reaction? C3H8O2(aq) + K2Cr2O7(aq) → C3H4O4(aq) + Cr+3(aq)

C

Balance the following redox reaction if it occurs in H2SO4. What are the coefficients in front of C3H8O2 and H2SO4 in the balanced reaction? C3H8O2(aq) + K2Cr2O7(aq) → C3H4O4(aq) + Cr2(SO4)3(aq)

C3H8O2 = 3, H2SO4 = 16

What element is being reduced in the following redox reaction? C3H8O2(aq) + KMnO4(aq) → C3H2O4K2(aq) + MnO2(aq) C Mn H K O

Mn

What is the shorthand notation that represents the following galvanic cell reaction? 2 Fe2+(aq) + F2(g) → 2 Fe3+(aq) + 2 F-(aq)

Pt(s) | Fe2+(aq), Fe3+(aq) || F2(g) | F-(aq) | C(s)

Do electrons flow toward or away from the cathode?

flow toward

Zn(s)+Na+(aq) → Zn2+(aq)+Na(s) Express your answer as a chemical equation. Identify all of the phases in your answer.

Zn(s)+2Na+(aq)→Zn2+(aq)+2Na(s)

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C. (The equation is balanced.) Mg(s) + Cu2+(aq) → Cu(s) + Mg2+(aq) Mg2+(aq) + 2 e- → Mg(s) E° = -2.38 V Cu2+(aq) + 2 e- → Cu(s) E° = +0.34 V

+2.72 V

An old iron beam was coated with an unknown metal. There is a crack on the coating and it is observed that the iron is rusting at the fracture. The beam is in a structure that experiences high stress, resulting in frequent fractures to the coating. What was the old metal coating likely made of and what metal you would use to repair the fractures to avoid further corrosion? Drag each label to the appropriate target.

1. 1. The old coating was likely made of TIN 2. ALUMINUM would be a good choice for repairing the fracture.

What is the balanced chemical equation for the galvanic cell reaction expressed using shorthand notation below? Al(s) | Al3+(aq) | Fe2+(aq) | Fe(s)

2 Al(s) + 3 Fe2+(aq) → 2 Al3+(aq) + 3 Fe(s)

#3 - Part A What are the coefficients of the reactants and products in the balanced equation above? Remember to include H2O(l) and H+(aq) in the appropriate blanks. Your answer should have six terms. Enter the equation coefficients in order separated by commas (e.g., 2,2,1,4,4,3). Include coefficients of 1, as required, for grading purposes.

2,1,4,2,1,2

Cl−(aq)+NO−3(aq) → NO(g)+Cl2(g) Express your answer as a chemical equation. Identify all of the phases in your answer.

6Cl−(aq)+8H+(aq)+2NO3−(aq)→3Cl2(g)+2NO(g)+4H2O(l)

What is undergoing reduction in the redox reaction represented by the following cell notation? Pb(s) | Pb 2+(aq) || H+(aq) | H2(g) | Pt

H+(aq)

Part complete Balance the following redox reaction if it occurs in H2SO4. What are the coefficients in front of H2O and Cr2(SO4)3 in the balanced reaction? C3H8O2(aq) + K2Cr2O7(aq) → C3H4O4(aq) + Cr2(SO4)3(aq)

H2O = 22, Cr2(SO4)3 = 4

Part complete What element is being oxidized in the following redox reaction? Mn 2+(aq) + NH4 +(aq) → Mn(s) + NO3 -(aq)

N

For the galvanic cell reaction, expressed below using shorthand notation, what half-reaction occurs at the cathode? Zn(s) | Zn2+(aq) | Ni2+(aq) | Ni(s)

Ni2+(aq) + 2 e- → Ni(s)

Part complete What element is being oxidized in the following redox reaction? H2O2(l) + ClO2(aq) → ClO2-(aq) + O2(g) C Cl O H N

O - Oxygen

Cathodic protection of iron involves using another more reactive metal as a sacrificial anode. Classify each of the following metals by whether they would or would not act as a sacrificial anode to iron. Drag each item to the appropriate bin. - Will act as sacrificial anode for iron

Zn Mg

Zn(s)+Sn2+(aq) → Zn2+(aq)+Sn(s) Express your answer as a chemical equation. Identify all of the phases in your answer.

Zn(s)+Sn2+(aq)→Zn2+(aq)+Sn(s)

What is the sign of the cathode?

positive (+)

Part complete What reaction (oxidation or reduction) occurs at the cathode of a voltaic cell?

reduction