2.1.5 Redox Flashcards

1
Q

What is an oxidation number?

A

The number of electrons an atom uses to bond with any other atom

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2
Q

What sit he oxidation number of an uncombined element such as C, H, O2

A

0

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3
Q

What is the oxidation number of combined oxygen such as in H2O?

A

-2

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4
Q

What is the oxidation number of oxygen in peroxides?

A

-1

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5
Q

What is the oxidation number of combined hydrogen such as in NH3, H2S?

A

+1

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6
Q

What is the oxidation number of combined hydrogen in metal hydrides such as LiH?

A

-1

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7
Q

What is the oxidation number of a simple ion?

A

Charge on the ion

e.g. Na+ = +1

Cl- = -1

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8
Q

What is the oxidation number of combined fluorine such as in NaF, CaF2?

A

-1

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9
Q

When an element has more than one stable oxidation number, how is it indicated

A

Written as a Roman numeral

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10
Q

What is the oxidation number of Fe in Iron (lll) chloride?

A

+3

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11
Q

What are oxyanions?

A

Negative ions that have an element along with oxygen

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12
Q

What is the oxidation number of S in SO4 ^2-

A

+6

Because, combined oxygen has an oxidation number of -2

4 x -2 = -8

The chrage on the compound is -2. Sum of oxidation numbers must equal -2

-2 -(-8) = +6

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13
Q

Define oxidation in terms of electron transfer and oxidation number

A

Oxidation is
loss of electrons
an increase in oxidation number

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14
Q

Define reduction in terms of electron transfer and oxidation number

A

Reduction is
Gain of electrons
A decrease in oxidation number

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15
Q

What is a redox reaction?

A

A reaction in which both oxidation and reduction takes place

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16
Q

What is the oxidation number of a metal?

A

0

because it is an uncombined element