What is a Mole? — BrainJoy

🔬 Step 1: Meet Avogadro's Number

One mole contains exactly 6.022 × 10²³ particles. That's called Avogadro's number.

6.022 × 10²³

particles in ONE mole

💡 Think of a mole like a chemistry version of a "dozen."

A dozen = 12 objects.
A mole = 602,200,000,000,000,000,000,000 objects.

🫧 Step 2: Count the Invisible

Use the slider to choose how many moles you have. The simulation represents the enormous number of particles using visible dots.

1.0 mol

6.022 × 10²³ particles

🧠 We obviously can't draw 6.022 × 10²³ dots on your screen. Instead, each visible dot represents an enormous group of particles.

🧮 Step 3: Moles → Particles

To calculate the number of particles, multiply the number of moles by Avogadro's number.

particles = moles × 6.022 × 10²³

1.2044 × 10²⁴

particles

⚖️ Step 4: Equal Moles, Different Masses

Here's something important: one mole is always the same number of particles, but different substances have different masses.

💧

Water

H₂O

18.02 g

1 mole

🧂

Salt

NaCl

58.44 g

1 mole

🫧

Carbon Dioxide

CO₂

44.01 g

1 mole

🎯 All three samples contain approximately 6.022 × 10²³ molecules or formula units.

But their masses are different because their particles have different masses.

🎯 The Big Idea

The mole is simply a counting unit.

1 mole = 6.022 × 10²³ particles

Once you understand that, chemistry becomes much easier. You can move between the microscopic world of atoms and molecules and the macroscopic world of grams.