Electrochem (day 1 Part A)

What are oxidation numbers?

Oxidation numbers represent the charges of atoms in a compound, indicating their valence or charge state.

How do you determine the oxidation number of arsenic in SO4^3-?

Arsenic has an oxidation number of +5, since the total charge must add up to -3 and the four oxygens contribute -8.

What does it mean for an element to be reduced?

An element is reduced when it gains electrons.

What does LEO stand for in the context of electrochemistry?

LEO stands for 'Loss of Electrons is Oxidation'.

If a compound's charge goes from +2 to 0, what happens to the electrons?

Electrons are gained, indicating that the element has been reduced.

How do you balance the charge in a redox reaction?

Add electrons to one side of the equation to make the charges equal on both sides.

What happens to the oxidation state of chlorine in Cl^-1 turning into Cl2?

Chlorine is oxidized as it loses electrons and its oxidation state increases.

What indicates that a substance has been oxidized?

An increase in oxidation state or a loss of electrons indicates oxidation.

What do you look for to determine which reactant is oxidized or reduced?

Always choose one of the reactants; the one losing electrons is oxidized, and the one gaining electrons is reduced.

If electrons appear on the left side of a half-reaction, what does that indicate?

It indicates that the substance is being reduced.

What is a common source of confusion when answering questions about oxidation and reduction?

Students often mistakenly choose products, whereas the correct choice is always a reactant.

How is oxidation represented in a reaction involving aluminum?

In the reaction Al^3+ turns into Al, it requires 3 electrons to reduce the aluminum, indicating reduction.

What is a common way to remember the concepts of oxidation and reduction?

Use the mnemonic 'LEO says GER,' meaning 'Loss of Electrons is Oxidation' and 'Gain of Electrons is Reduction.'