Mostly Electrochemistry and Redox

Given the unbalanced equation Cr⁰ + Sn²⁺ → Cr³⁺ + Sn⁰ What is the coefficient in front of the Cr³⁺ when the equation is balanced using smallest whole-number coefficients?

• 1

• 2

• 3

• 6

Tags

NGSS.HS-PS1-7

What is the total number of moles of electrons needed to completely reduce 6.0 moles of Ni²⁺(aq) ions?

• 6.0 moles

• 3.0 moles

• 12.0 moles

• 1.0 mole

Given the balanced ionic equation: 2Al(s) + 3Cu²⁺(aq) → 2Al³⁺(aq) + 3Cu(s) Compared to the total charge of the reactants, the total charge of the products is

• less

• greater

• the same

Which half-reaction shows conservation of charge?

• Cu + e⁻ → Cu⁺

• Cu²⁺ + 2e⁻ → Cu

• Cu⁺ → Cu + e⁻

• Cu²⁺ → Cu + 2e⁻

Base your answer(s) to the following question(s) on the diagram below. The diagram shows a voltaic cell with copper and aluminum electrodes immediately after the external circuit is completed. Balance the redox equation using the smallest whole-number coefficients. ____ Cu²⁺(aq) + ____ Al(s) → ____ Cu(s) + ____ Al³⁺(aq) Fill in the blank for the coefficient of Cu²⁺(aq).

• 3

• 1

• 2

• 6

Base your answer(s) to the following question(s) on the diagram below. The diagram shows a voltaic cell with copper and aluminum electrodes immediately after the external circuit is completed. Balance the redox equation using the smallest whole-number coefficients. __Cu²⁺(aq) + ____ Al(s) → 3 Cu(s) + ____ Al³⁺(aq) What is the coefficient of Al(s)?

• 2

• 1

• 3

• 6

In a redox reaction, the total number of electrons lost is

• less than the total number of electrons gained

• greater than the total number of electrons gained

• equal to the total number of electrons gained

• equal to the total number of protons gained

Tags

NGSS.HS-PS1-7

Balance the equation below for the redox reaction that occurs in this cell, using the smallest whole-number coefficients. ______ Zn(s) + ______ Fe³⁺(aq) → ______ Zn²⁺ + ______ Fe(s)

• 3 Zn(s) + 2 Fe³⁺(aq) → 3 Zn²⁺ + 2 Fe(s)

• 2 Zn(s) + 3 Fe³⁺(aq) → 2 Zn²⁺ + 3 Fe(s)

• 2 Zn(s) + 3 Fe³⁺(aq) → 2 Zn²⁺ + 3 Fe(s)

• 2 Zn(s) + Fe³⁺(aq) → 2 Zn²⁺ + Fe(s)

Which equation represents conservation of charge?

• I⁻ + 2e⁻ → I₂

• 2I⁻ → I₂ + 2e⁻

• Br₂ → 2Br⁻ + 2e⁻

• Br + 2e⁻ → Br⁻

The balanced, half-reaction equation for the reduction of the copper ions is:

• Cu²⁺ + 2e⁻ → Cu(s)

• Cu(s) → Cu²⁺ + 2e⁻

• Cu⁺ + e⁻ → Cu(s)

• Cu²⁺ → Cu(s) + 2e⁻

Tags

NGSS.HS-PS1-2