Redox Pretest

What changes occur in the oxidation states in the reaction: 2K(s) + Cl₂(g) → 2KCl(s)

• K: 0 to +1, Cl: 0 to -1

• K: 0 to -1, Cl: 0 to +1

• K: +1 to 0, Cl: -1 to 0

• K: 0 to 0, Cl: 0 to 0

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

In the reaction: 3FeCl₃ + 2Al → 3Fe + 2AlCl₃ What is the oxidation number of iron before and after the reaction?

• +3 to 0

• 0 to +3

• +2 to 0

• +3 to +2

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which value changes when a neutral Zn atom becomes a Zn²⁺ ion?

• Proton number

• Neutron number

• Oxidation number

• Mass number

Which of the following is a valid reduction half-reaction?

• Fe → Fe³⁺ + 3e⁻

• Cl₂ + 2e⁻ → 2Cl⁻

• Mg → Mg²⁺ + 2e⁻

• Cu⁺ → Cu²⁺ + e⁻

Which metal is most likely to be oxidized based on its activity?

• Au

• Mg

• Ag

• Pt

In the reaction: Zn + Cu²⁺ → Zn²⁺ + Cu Which is the oxidation half-reaction?

• Zn²⁺ + 2e⁻ → Zn

• Cu²⁺ + 2e⁻ → Cu

• Zn → Zn²⁺ + 2e⁻

• Cu → Cu²⁺ + 2e⁻

Which of the following represents a reduction half-reaction?

• Na → Na⁺ + e⁻

• Br₂ + 2e⁻ → 2Br⁻

Which process involves using electrical energy to drive a chemical change?

• Combustion

• Electrolysis

• Melting

• Evaporation

Tags

NGSS.HS-PS3-5

In any redox reaction, how do electrons gained compare to electrons lost?

• More electrons are gained

• Equal number are gained and lost

• More electrons are lost

• No electrons are transferred

What happens when Fe³⁺ is reduced to Fe²⁺?

• Oxidation number increases by 1

• One electron is lost

• One electron is gained

• Two electrons are gained

Tags

NGSS.HS-PS1-2