AP CHEM Unit 3 In Class Review

In the reaction of permanganate anion with iodide in acidic solution

2MnO₄⁻ + 16H⁺ + 10 I⁻ → 2 Mn²⁺ + 8H₂O + 5 I₂

what has been reduced and what is its change in oxidation number?

• iodine;

  from −1 to 0

• manganese;

  from +7 to +2

• oxygen;

  from −1 to −2

• hydrogen;

  from +1 to 0

Tags

NGSS.HS-PS1-2

When the equation below is correctly balanced, the coefficients, in order, are:

___Li(s) + ___Mg²⁺(aq) → ___Li⁺(aq) + ___Mg(s)

• 2, 1, 2, 1

• 1, 1, 1, 1

• 1, 1, 2, 1

• 1, 2, 1, 1,

Tags

NGSS.HS-PS1-7

3Sn²⁺(aq) + Cr₂O₇^2-(aq) + 14H⁺(aq) → 3Sn⁴⁺(aq) + 2Cr³⁺(aq) + 7H₂O(l)

The equation shown represents the reaction performed in a REDOX titration. Which of the following is true regarding the stoichiometry and the REDOX process in the equation?

• Three times the number of Sn²⁺ ions are consumed as Cr₂O₇^2- ions consumed.

  Sn²⁺ is oxidized to Sn⁴⁺.

• One-third the number of Sn²⁺ ions are consumed as Cr₂O₇^2- ions consumed.

  Sn²⁺ is oxidized to Sn⁴⁺.

• Three times the number of Sn²⁺ ions are consumed as Cr₂O₇^2- ions consumed.

  Sn²⁺ is reduced to Sn⁴⁺.

• One-third the number of Sn²⁺ ions are consumed as Cr₂O₇^2- ions consumed.

  Sn²⁺ is reduced to Sn⁴⁺.

Tags

NGSS.HS-PS1-2

6I^-(aq) + 4H₂O(l) + 2MnO₄^-(aq) → 3I₂(aq) + 2MnO₂(s) + 8OH^-(aq)

The equation shown represents the reaction performed in a REDOX titration. Which of the following is true regarding the stoichiometry and the REDOX process in the equation?

• Three times the number of MnO₄^- ions are consumed as I^- ions consumed.

  I^- is oxidized to I₂.

• One-third the number of MnO₄^- ions are consumed as I^- ions consumed.

  I^- is oxidized to I₂.

• One-third the number of MnO₄^- ions are consumed as I^- ions consumed.

  I^- is reduced to I₂.

• Three times the number of MnO₄^- ions are consumed as I^- ions consumed.

  I^- is reduced to I₂.

Tags

NGSS.HS-PS1-2

In this electrochemical cell, if the salt bridge is removed what happens to the voltage?

• E_cell = 0.00V

• E_cell = +2.31V

• 0.00V < E_cell < +2.31V

• E_cell > +2.31V

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-5

In this electrochemical cell, if the Cr electrode is replaced with an inert electrode what happens to the voltage?

• E_cell = 0.00V

• E_cell = +2.31V

• 0.00V < E_cell < +2.31V

• E_cell > +2.31V

Tags

NGSS.HS-PS1-2

In this electrochemical cell, if the Li electrode is replaced with an inert electrode what happens to the voltage?

• E_cell = 0.00V

• E_cell = +2.31V

• 0.00V < E_cell < +2.31V

• E_cell > +2.31V

Tags

NGSS.HS-PS1-2

If E° is positive, ∆G° must be _____________ and K must be _____________ than 1.

• negative, less

• negative, greater

• positive, less

• positive, greater

Tags

NGSS.HS-PS1-4

A reaction

3 A²⁺ + 2 B → 3 A + 2 B³⁺

is used to make a battery. The standard Gibbs free energy change for the given reaction is −972 kJ. What is the standard potential (E⁰_cell) for the battery?

HINT: Watch your units!

• 
• 
• 
• 

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Cu²⁺(aq) + Zn(s) → Cu(s) + Zn²⁺(aq)

E⁰_cell= +1.10V

Which of the following is true for the reaction shown? Select ALL that apply.

• Cu²⁺ is oxidized.

• Zn is oxidized at the cathode.

• The equilibrium constant, K_eq, is greater than 1.

• The Gibbs Free Energy, ΔG, is negative.

Tags

NGSS.HS-PS1-2