Question 1

What is the reduction half reaction for the following chemical reaction in a basic solution? ClO^-(aq)+ Cr(OH)₄^-(aq)→ CrO₄^2-(aq)+ Cl^-(aq)

Accepted Answer

The first step to determining the reduction half reaction is to identify which species is being reduced. In this case, we can see that chromium (Cr) is going from a +3 oxidation state to a +2 oxidation state, which means it is gaining electrons and being reduced. Therefore, the reduction half reaction should involve the Cr species.

Next, we need to balance the charges and add water molecules to balance the oxygen atoms. The balanced reduction half reaction is:

Cr(OH)4^- + 6e^- → Cr(OH)2 + 4OH^-

However, the question asks for the reduction half reaction in a basic solution, so we need to add enough hydroxide ions (OH^-) to balance out the hydrogen ions (H+) on the other side of the equation. In this case, we need to add 4 more OH^- ions to both sides of the equation:

Cr(OH)4^- + 10e^- + 4OH^- → Cr(OH)2 + 6OH^-

This final equation matches option B.

Question 2

Determine the number of water molecules necessary to balance the reduction half reaction of  that occurs in an acidic solution.

Accepted Answer

The reduction half-reaction of 11ea7e2d_d1a1_ef5a_a2f7_e7fe24ea2aa3_TB4940_00 is:
Cr2O7^2- + 14H+ + 6e- -> 2Cr3+ + 7H2O
To balance the half-reaction, there are 6 electrons on the left-hand side and 14 hydrogen ions and 7 water molecules on the right-hand side. To balance the hydrogen ions, we need to add water molecules to the right-hand side:
Cr2O7^2- + 14H+ + 6e- -> 2Cr3+ + 7H2O(l)
To balance the oxygen atoms, we need to add 7 water molecules to the left-hand side of the equation:
Cr2O7^2-(aq) +14H+(aq) + 6e-(aq) → 2Cr3+(aq) + 7H2O(l)
So the answer is 7.

Question 3

What species is oxidized in the reaction: CuSO₄(aq)+ Mg(s)→ MgSO₄(aq)+ Cu(s)?

Accepted Answer

Mg is oxidized because it loses electrons to form MgSO₄(aq), while CuSO₄(aq) is reduced to Cu(s) by gaining electrons. Therefore, the species undergoing oxidation is Mg.

Question 4

For a galvanic cell,the cathode has a ________ sign and is the site of ________.

Accepted Answer

In a galvanic cell, the cathode is positively charged and is the site where reduction occurs.

Question 5

Determine the number of water molecules necessary to balance the following chemical equation. Cr₂O₇^2-(aq)+ Cl^-(aq)+ H⁺(aq)→ Cr³⁺(aq)+ Cl₂(g)+ ________ H₂O(l)

Accepted Answer

According to the balanced equation, there are 17 oxygen atoms on the left side and only 1 on the right side. To balance this, we need to add 16 more oxygen atoms. This can be done by adding 8 water molecules (each contributing 2 oxygen atoms) to the right side, giving us a total of 16 oxygen atoms. Additionally, the equation requires 12 hydrogen atoms on the left side and only 1 on the right side. Adding 11 more hydrogen atoms can be done by adding 11 H+ (protons) to the right side, which can be neutralized by adding 11 H2O (water) molecules. Therefore, the total number of water molecules needed to balance the equation is 8 + 11 = 19. However, since there are already 12 water molecules on the left side, we only need to add 7 more water molecules to the right side. Therefore, the answer is C) 7.

Question 6

What is the molarity of a potassium triiodide solution,KI₃(aq),if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.200 M thiosulfate solution,Na₂S₂O₃(aq)? The chemical equation for the reaction is:

Accepted Answer

The answer of What is the molarity of a potassium...

Question 7

What are the coefficients in front of NO₃^-(aq)and Cu(s)when the following redox equation is balanced in an acidic solution: ________ NO₃^-(aq)+ ________ Cu(s)→ ________ NO(g)+ ________ Cu²⁺(aq)?

Accepted Answer

In order to balance the equation, the number of electrons lost by Cu must equal the number of electrons gained by NO₃^-(aq). This requires the coefficient of Cu to be 3 and the coefficient of NO₃^-(aq) to be 2. Therefore, the coefficients in front of Cu and NO₃^-(aq) are 3 and 2, respectively.

Question 8

Based on the balanced chemical equation shown below,determine the mass percent of Fe³⁺ in a 0.6450 gram sample of iron ore,if 22.40 mL of a 0.1000 M stannous chloride,SnCl₂(aq),solution is required to completely react with the Fe³⁺ present in the ore sample.The chemical equation for the reaction is: 2 Fe³⁺(aq)+ Sn²⁺(aq)→ 2 Fe²⁺(aq)+ Sn⁴⁺(aq).

Accepted Answer

The answer of Based on the balanced chemical equation shown...

Question 9

Based on the balanced chemical equation shown below,determine the molarity of a solution containing Fe²⁺(aq),if 40.00 mL of the Fe²⁺(aq)solution is required to completely react with 30.00 mL of a 0.125 M potassium bromate,KBrO₃(aq),solution.The chemical equation for the reaction is: 6 Fe²⁺(aq)+ BrO₃^-(aq)+ 6 H⁺(aq)→ 6 Fe³⁺(aq)+ Br^-(aq)+ 3 H₂O(l).

Accepted Answer

The stoichiometry of the reaction shows that 6 moles of Fe²⁺ react with 1 mole of BrO₃⁻. Using the molarity and volume of KBrO₃, calculate moles of BrO₃⁻, then use stoichiometry to find moles of Fe²⁺. Finally, divide by the volume of Fe²⁺ solution in liters to find its molarity.

Question 10

In a galvanic cell,the half-reaction H₂(g)+ 2 OH^-(aq)→ 2 H₂O(l)+ 2 e^-is

Accepted Answer

This half-reaction shows the loss of electrons (2 e⁻ on the product side), which defines it as an oxidation process. In a galvanic cell, oxidation occurs at the anode.

Question 11

According to the balanced equation shown below,1.00 mole of oxalic acid,H₂C₂O₄,reacts with ________ moles of permanganate ion,MnO₄^-. 5 H₂C₂O₄(aq)+ 2 MnO₄^-(aq)+ 6 H⁺(aq)→ 10 CO₂(g)+ 2 Mn²⁺(aq)+ 8 H₂O(l)

Accepted Answer

According to the balanced equation, 5 moles of oxalic acid react with 2 moles of permanganate ion. Therefore, 1 mole of oxalic acid reacts with 0.4 moles of permanganate ion (2/5 = 0.4).

Question 12

During an electrochemical reaction,electrons move through the external circuit toward the ________ and positive ions in the cell move toward the ________.

Accepted Answer

In an electrochemical reaction, electrons move through the external circuit toward the cathode, and positive ions in the cell move toward the cathode.

Question 13

Which of the following terms can be used to describe an electrochemical cell in which a spontaneous chemical reaction generates an electric current? I.an electrolytic cell
II.a galvanic cell
III.a voltaic cell

Accepted Answer

Both galvanic cells and voltaic cells involve spontaneous chemical reactions generating an electric current. The term "galvanic cell" is generally used for cells that use spontaneous redox reactions to generate electrical energy. "Voltaic cell" is a more general term that can refer to any type of electrochemical cell that generates an electric current through spontaneous chemical reactions. "Electrolytic cell" is a type of cell that drives non-spontaneous redox reactions using an external voltage source, and is not the appropriate term for a cell in which a spontaneous reaction generates current.

Question 14

What is the oxidation half reaction in the following chemical reaction? Cr₂O₇^2-(aq)+ 6 Cl^-(aq)+ 14 H⁺(aq)→ 2 Cr³⁺(aq)+ 3 Cl₂(aq)+ 7 H₂O(l)

Accepted Answer

The oxidation half-reaction involves the loss of electrons. In this reaction, Cl⁻ ions are oxidized to Cl₂, losing electrons in the process.

Question 15

What is true when the following equation is balanced in basic solution? P(s)+ PO₄^3-(aq)→ HPO₃^2-(aq)

Accepted Answer

The answer of What is true when the following equation...

Question 16

In a galvanic cell,the half-reaction MnO₄^-(aq)+ 8 H⁺(aq)+ 5 e^- → Mn²⁺(aq)+ 4 H₂O(l)is

Accepted Answer

The given half-reaction involves the gain of electrons (reduction), and in a galvanic cell, reduction occurs at the cathode.

Question 17

Based on the balanced chemical equation shown below,what volume of 0.250 M K₂S₂O₃₍_aq₎ is needed to completely react with 12.44 mL of 0.125 M KI₃(aq)? 2 S₂O₃^2-(aq)+ I₃^-(aq)→ S₄O₆^2-(aq)+ 3 I^-(aq)

Accepted Answer

First, use the balanced chemical equation to determine the mole ratio between KI and Na2S2O3:

1 mol KI reacts with 2 mol Na2S2O3

Then, use the concentration and volume of KI to calculate the number of moles present:

moles KI = concentration x volume = 0.125 M x 12.44 mL x (1 L / 1000 mL) = 0.001555 mol

Finally, use the mole ratio to determine the volume of Na2S2O3 needed:

moles Na2S2O3 = (0.001555 mol KI) x (2 mol Na2S2O3 / 1 mol KI) = 0.00311 mol

volume Na2S2O3 = moles / concentration = 0.00311 mol / 0.250 M = 0.0124 L = 12.4 mL

Therefore, the best choice is C, 12.4 mL.

Question 18

Determine the number of water molecules necessary to balance the reduction half reaction of  that occurs in a basic solution.

Accepted Answer

The answer of Determine the number of water molecules necessary...

Question 19

According to the balanced chemical equation 5 H₂C₂O₄(aq)+ 2 MnO₄^-(aq)+ 6 H⁺(aq)→ 10 CO₂(g)+ 2 Mn²⁺(aq)+ 8 H₂O(l) 0.3500 grams of oxalic acid,H₂C₂O₄ will react with ________ mL of 0.100 M potassium permanganate,KMnO₄ solution.

Accepted Answer

To balance the equation, we need 5 moles of oxalic acid for every 2 moles of potassium permanganate. Therefore, 0.3500 g of oxalic acid will react with:(0.3500 g oxalic acid) x (1 mol oxalic acid/90.03 g oxalic acid) x (2 mol potassium permanganate/5 mol oxalic acid) x (1000 mL potassium permanganate/1 mol potassium permanganate) x (1 L/1000 mL) = 15.5 mL potassium permanganate

Question 20

Which cell involves a nonspontaneous redox reaction?

Accepted Answer

In an electrolytic cell, a nonspontaneous redox reaction is driven by an external power source. This is in contrast to a galvanic cell, where a spontaneous redox reaction produces an electric current. Concentration cells and fuel cells both involve spontaneous redox reactions.

Quiz 18: Electrochemistry

What is the reduction half reaction for the following chemical reaction in a basic solution? ClO^-(aq) + Cr(OH) ₄^-(aq) → CrO₄^2-(aq) + Cl^-(aq)

Determine the number of water molecules necessary to balance the reduction half reaction of that occurs in an acidic solution.

What species is oxidized in the reaction: CuSO₄(aq) + Mg(s) → MgSO₄(aq) + Cu(s) ?

For a galvanic cell,the cathode has a sign and is the site of .

Determine the number of water molecules necessary to balance the following chemical equation. Cr₂O₇^2-(aq) + Cl^-(aq) + H⁺(aq) → Cr³⁺(aq) + Cl₂(g) + ________ H₂O(l)

What is the molarity of a potassium triiodide solution,KI₃(aq) ,if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.200 M thiosulfate solution,Na₂S₂O₃(aq) ? The chemical equation for the reaction is:

What are the coefficients in front of NO₃^-(aq) and Cu(s) when the following redox equation is balanced in an acidic solution: NO₃^-(aq) + Cu(s) → NO(g) + Cu²⁺(aq) ?

In a galvanic cell,the half-reaction H₂(g) + 2 OH^-(aq) → 2 H₂O(l) + 2 e^-is

According to the balanced equation shown below,1.00 mole of oxalic acid,H₂C₂O₄,reacts with ________ moles of permanganate ion,MnO₄^-. 5 H₂C₂O₄(aq) + 2 MnO₄^-(aq) + 6 H⁺(aq) → 10 CO₂(g) + 2 Mn²⁺(aq) + 8 H₂O(l)

During an electrochemical reaction,electrons move through the external circuit toward the and positive ions in the cell move toward the .

Which of the following terms can be used to describe an electrochemical cell in which a spontaneous chemical reaction generates an electric current? I.an electrolytic cell II.a galvanic cell III.a voltaic cell

What is the oxidation half reaction in the following chemical reaction? Cr₂O₇^2-(aq) + 6 Cl^-(aq) + 14 H⁺(aq) → 2 Cr³⁺(aq) + 3 Cl₂(aq) + 7 H₂O(l)

What is true when the following equation is balanced in basic solution? P(s) + PO₄^3-(aq) → HPO₃^2-(aq)

In a galvanic cell,the half-reaction MnO₄^-(aq) + 8 H⁺(aq) + 5 e^- → Mn²⁺(aq) + 4 H₂O(l) is

Based on the balanced chemical equation shown below,what volume of 0.250 M K₂S₂O₃₍_aq₎ is needed to completely react with 12.44 mL of 0.125 M KI₃(aq) ? 2 S₂O₃^2-(aq) + I₃^-(aq) → S₄O₆^2-(aq) + 3 I^-(aq)

Determine the number of water molecules necessary to balance the reduction half reaction of that occurs in a basic solution.

According to the balanced chemical equation 5 H₂C₂O₄(aq) + 2 MnO₄^-(aq) + 6 H⁺(aq) → 10 CO₂(g) + 2 Mn²⁺(aq) + 8 H₂O(l) 0.3500 grams of oxalic acid,H₂C₂O₄ will react with ________ mL of 0.100 M potassium permanganate,KMnO₄ solution.

Which cell involves a nonspontaneous redox reaction?

Quiz 18: Electrochemistry

What is the reduction half reaction for the following chemical reaction in a basic solution? ClO-(aq) + Cr(OH) 4-(aq) → CrO42-(aq) + Cl-(aq)

Determine the number of water molecules necessary to balance the reduction half reaction of that occurs in an acidic solution.

What species is oxidized in the reaction: CuSO4(aq) + Mg(s) → MgSO4(aq) + Cu(s) ?

For a galvanic cell,the cathode has a ________ sign and is the site of ________.

Determine the number of water molecules necessary to balance the following chemical equation. Cr2O72-(aq) + Cl-(aq) + H+(aq) → Cr3+(aq) + Cl2(g) + ________ H2O(l)

What is the molarity of a potassium triiodide solution,KI3(aq) ,if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.200 M thiosulfate solution,Na2S2O3(aq) ? The chemical equation for the reaction is:

What are the coefficients in front of NO3-(aq) and Cu(s) when the following redox equation is balanced in an acidic solution: ________ NO3-(aq) + ________ Cu(s) → ________ NO(g) + ________ Cu2+(aq) ?

In a galvanic cell,the half-reaction H2(g) + 2 OH-(aq) → 2 H2O(l) + 2 e- is

According to the balanced equation shown below,1.00 mole of oxalic acid,H2C2O4,reacts with ________ moles of permanganate ion,MnO4-. 5 H2C2O4(aq) + 2 MnO4-(aq) + 6 H+(aq) → 10 CO2(g) + 2 Mn2+(aq) + 8 H2O(l)

During an electrochemical reaction,electrons move through the external circuit toward the ________ and positive ions in the cell move toward the ________.

Which of the following terms can be used to describe an electrochemical cell in which a spontaneous chemical reaction generates an electric current? I.an electrolytic cell II.a galvanic cell III.a voltaic cell

What is the oxidation half reaction in the following chemical reaction? Cr2O72-(aq) + 6 Cl-(aq) + 14 H+(aq) → 2 Cr3+(aq) + 3 Cl2(aq) + 7 H2O(l)

What is true when the following equation is balanced in basic solution? P(s) + PO43-(aq) → HPO32-(aq)

In a galvanic cell,the half-reaction MnO4-(aq) + 8 H+(aq) + 5 e- → Mn2+(aq) + 4 H2O(l) is

Based on the balanced chemical equation shown below,what volume of 0.250 M K2S2O3(aq) is needed to completely react with 12.44 mL of 0.125 M KI3(aq) ? 2 S2O32-(aq) + I3-(aq) → S4O62-(aq) + 3 I-(aq)

Determine the number of water molecules necessary to balance the reduction half reaction of that occurs in a basic solution.

According to the balanced chemical equation 5 H2C2O4(aq) + 2 MnO4-(aq) + 6 H+(aq) → 10 CO2(g) + 2 Mn2+(aq) + 8 H2O(l) 0.3500 grams of oxalic acid,H2C2O4 will react with ________ mL of 0.100 M potassium permanganate,KMnO4 solution.

Which cell involves a nonspontaneous redox reaction?

What is the reduction half reaction for the following chemical reaction in a basic solution? ClO^-(aq) + Cr(OH) ₄^-(aq) → CrO₄^2-(aq) + Cl^-(aq)

What species is oxidized in the reaction: CuSO₄(aq) + Mg(s) → MgSO₄(aq) + Cu(s) ?

For a galvanic cell,the cathode has a sign and is the site of .

Determine the number of water molecules necessary to balance the following chemical equation. Cr₂O₇^2-(aq) + Cl^-(aq) + H⁺(aq) → Cr³⁺(aq) + Cl₂(g) + ________ H₂O(l)

What is the molarity of a potassium triiodide solution,KI₃(aq) ,if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.200 M thiosulfate solution,Na₂S₂O₃(aq) ? The chemical equation for the reaction is:

What are the coefficients in front of NO₃^-(aq) and Cu(s) when the following redox equation is balanced in an acidic solution: NO₃^-(aq) + Cu(s) → NO(g) + Cu²⁺(aq) ?

In a galvanic cell,the half-reaction H₂(g) + 2 OH^-(aq) → 2 H₂O(l) + 2 e^-is

According to the balanced equation shown below,1.00 mole of oxalic acid,H₂C₂O₄,reacts with ________ moles of permanganate ion,MnO₄^-. 5 H₂C₂O₄(aq) + 2 MnO₄^-(aq) + 6 H⁺(aq) → 10 CO₂(g) + 2 Mn²⁺(aq) + 8 H₂O(l)

During an electrochemical reaction,electrons move through the external circuit toward the and positive ions in the cell move toward the .

What is the oxidation half reaction in the following chemical reaction? Cr₂O₇^2-(aq) + 6 Cl^-(aq) + 14 H⁺(aq) → 2 Cr³⁺(aq) + 3 Cl₂(aq) + 7 H₂O(l)

What is true when the following equation is balanced in basic solution? P(s) + PO₄^3-(aq) → HPO₃^2-(aq)

In a galvanic cell,the half-reaction MnO₄^-(aq) + 8 H⁺(aq) + 5 e^- → Mn²⁺(aq) + 4 H₂O(l) is

Based on the balanced chemical equation shown below,what volume of 0.250 M K₂S₂O₃₍_aq₎ is needed to completely react with 12.44 mL of 0.125 M KI₃(aq) ? 2 S₂O₃^2-(aq) + I₃^-(aq) → S₄O₆^2-(aq) + 3 I^-(aq)

According to the balanced chemical equation 5 H₂C₂O₄(aq) + 2 MnO₄^-(aq) + 6 H⁺(aq) → 10 CO₂(g) + 2 Mn²⁺(aq) + 8 H₂O(l) 0.3500 grams of oxalic acid,H₂C₂O₄ will react with ________ mL of 0.100 M potassium permanganate,KMnO₄ solution.