Electrochemistry: common misconceptions

If your child says… “The salt bridge carries electrons.”

Ask together

Which route connects the metal electrodes directly?

What’s true

The wire carries electrons, while ions move through the salt bridge.

If your child says… “Every hydrogen electrode has zero potential.”

Ask together

Would changing hydrogen pressure still meet those standard conditions?

What’s true

Only the hydrogen electrode under specified standard conditions is assigned zero volts.

If your child says… “The voltage always equals the standard voltage.”

Ask together

Why did the calculation subtract something from 1.10 V?

What’s true

Changing ion concentrations can change voltage even when the electrode materials stay unchanged.

If your child says… “Both conductivity and molar conductivity fall when we add water.”

Ask together

Does fewer ions per volume mean each mole must contribute less?

What’s true

For these dilute salt solutions, dilution lowers conductivity but raises molar conductivity.

If your child says… “We count each kind of ion only once.”

Ask together

How many chloride ions does one calcium chloride formula unit supply?

What’s true

Each ion’s contribution must include how many of that ion the formula supplies.

If your child says… “One faraday makes one mole of any product.”

Ask together

Will the same electron amount form equal numbers of sodium atoms and chlorine molecules?

What’s true

One faraday supplies one mole of electrons, so product amounts depend on their electron requirements.

If your child says… “Every battery can be recharged.”

Ask together

Which system has a charging arrow that reverses its discharge arrow?

What’s true

Primary cells are not designed for safe recharging.

If your child says… “Dry iron simply joins with oxygen to make rust.”

Ask together

What does the coating keep from reaching the iron easily?

What’s true

Rusting needs water, with electrons moving through iron and ions through the surface water.