Redox Reaction Calculator

This Redox Reaction calculator uses the Nernst Equation to find the voltage of your redox reaction. Don’t worry, you don’t need to memorize the formula! Just enter your values and we’ll do the math.

The Formula We Use

E = E° – (RT/nF) × log₁₀(Q)

What each letter means:

• E = Cell potential (what we’re finding)
• E° = Standard potential (from reference tables)
• R = Gas constant (8.314)
• T = Temperature in Kelvin
• n = Number of electrons moved
• F = Faraday constant (96485)
• Q = Reaction quotient (concentration ratio)

How to use this Calculator

Step 1: Find Your Standard Potential (E°)

This comes from chemistry reference tables. Common values include:

• Zn²⁺ + 2e⁻ → Zn: -0.76 V
• Cu²⁺ + 2e⁻ → Cu: +0.34 V
• Ag⁺ + e⁻ → Ag: +0.80 V

Tip: Your textbook or lab manual usually has these values!

Step 2: Count Electrons Transferred (n)

Look at your balanced equation and count how many electrons move from one atom to another.

Examples:

• Zn → Zn²⁺ + 2e⁻: n = 2
• Cu²⁺ + 2e⁻ → Cu: n = 2
• Fe³⁺ + e⁻ → Fe²⁺: n = 1

Step 3: Calculate the Reaction Quotient (Q)

This shows the ratio of products to reactants in your reaction.

Formula: Q = [Products]/[Reactants]

Example: For Zn + Cu²⁺ → Zn²⁺ + Cu Q = [Zn²⁺]/[Cu²⁺]

Step 4: Convert Temperature to Kelvin

If temperature is in Celsius, add 273.15

Examples:

• 25°C = 298.15 K (room temperature)
• 0°C = 273.15 K
• 100°C = 373.15 K

Step 5: Enter Values and Calculate!

Put all your numbers into our calculator and hit “Calculate” for instant results!

Real Example Copper-Zinc Cell

Let’s calculate the voltage of a simple battery:

Reaction: Zn + Cu²⁺ → Zn²⁺ + Cu

Given Information:

• E° = +1.10 V (from reference table)
• n = 2 electrons
• [Zn²⁺] = 0.1 M, [Cu²⁺] = 1.0 M
• T = 25°C = 298.15 K

Using Our Calculator:

1. Standard Potential: 1.10 V
2. Electrons: 2
3. Q: 0.1/1.0 = 0.1
4. Temperature: 298.15 K

Result: E = 1.13 V

Frequently Asked Questions