Redox Reactions

A redox reaction is NOT:

• all reactions

• a single replacement reaction

• a reduction-oxidation reaction

• a reaction in which electrons are transferred from one atom to another

Answer explanation

A redox reaction specifically involves the transfer of electrons between atoms. Therefore, not all reactions qualify as redox reactions, making 'all reactions' the correct choice for what a redox reaction is NOT.

Tags

NGSS.HS-PS1-2

Single-replacement reactions are __________ redox reactions.

• always

• never

• sometimes

• mostly

Answer explanation

Single-replacement reactions involve the transfer of electrons, making them redox reactions. Since they always involve oxidation and reduction processes, the correct answer is 'always'.

Tags

NGSS.HS-PS1-2

_____________ synthesis and decomposition reactions involve the transfer of electrons.

• All

• Most

• No

• Some

Answer explanation

Most synthesis and decomposition reactions involve electron transfer, as they typically include oxidation and reduction processes. Therefore, the correct choice is 'Most'.

Tags

NGSS.HS-PS1-2

Defined as the loss of electrons.

• oxidation

• reduction

• redox

• OIL RIG

Answer explanation

Oxidation is defined as the loss of electrons. In contrast, reduction refers to the gain of electrons. The term 'redox' encompasses both processes, while 'OIL RIG' is a mnemonic for remembering that Oxidation Is Loss.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Defined as the gain of electrons.

• oxidation

• redox

• reduction

• LEO GER

Answer explanation

Reduction is defined as the gain of electrons, which is the opposite of oxidation. In redox reactions, reduction and oxidation occur simultaneously, but here, the focus is on the process of gaining electrons.

Tags

NGSS.HS-PS1-2

What is being oxidized in the following equation?

2 K + l₂ --> 2 KCl

• K

• I

Answer explanation

In the reaction, potassium (K) is oxidized as it loses electrons to form KCl. The iodine (I) is reduced, gaining electrons. Therefore, K is the species being oxidized.

Tags

NGSS.HS-PS1-2

These keep track of the movement of electrons.

• (+) and (-) signs

• oxidation numbers

• coefficients

• subscripts

Answer explanation

Oxidation numbers indicate the charge of an atom in a compound, reflecting the movement of electrons during chemical reactions. They help track electron transfer, making them the correct choice for this question.

Tags

NGSS.HS-PS2-5

An increase in oxidation number.

• more acidic

• reduction

• less basic

• oxidation

Answer explanation

An increase in oxidation number indicates the loss of electrons, which is defined as oxidation. Therefore, the correct answer is oxidation.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

A decrease in oxidation number.

• concentrated

• reduction

• oxidation

• dilute

Answer explanation

A decrease in oxidation number indicates that a substance is gaining electrons, which is defined as reduction. Therefore, the correct answer is reduction.

What is the oxidation number of Mn in MnCO₃?

• -4

• +2

• -1

• +4

Answer explanation

In MnCO3, the carbonate ion (CO3) has an oxidation number of -2. To balance this, Mn must have an oxidation number of +2, making the correct answer +2.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2