Chapter 13 - Redox Reactions

Question 1

What is the basis of an electrochemical reaction?

Answer 1

Electron transfer.

Question 2

What type of reactions are the most common in both living and nonliving systems?

Answer 2

Electrochemical reactions.

Question 3

Some examples of electrochemical processes are:

Answer 3

Photosynthesis, cellular respiration, and metabolism.

Question 4

Do gold and silver naturally exist as a pure element?

Answer 4

Yes.

Question 5

What are ores?

Answer 5

Rocks in which most elements exist mixed with other elements.

Question 6

What is metallurgy?

Answer 6

extracting metals from their naturally occurring compounds.

Question 7

What is reduction (historical)?

Answer 7

Producing metals from their compounds.

Question 8

What is oxidation (historical)?

Answer 8

The process of a substance reacting with oxygen (like corrosion or combustion).

Question 9

What does a reducing agent do?

Answer 9

Causes or promotes reduction.

Question 10

What does an oxidizing agent do?

Answer 10

Causes or promotes oxidation.

Question 11

What are the most common reducing agents used in metallurgical processes?

Answer 11

Carbon monoxide, carbon, and hydrogen.

Question 12

what is the main difference between corrosion and combustion?

Answer 12

Corrosion occurs more slowly.

Question 13

Corrosion could be considered the opposite of…

Answer 13

Metallurgy.

Question 14

What is a half reaction?

Answer 14

A balanced chemical equation that shows either the loss or gain of electrons of a substance.

Question 15

The gain of electrons is:

Answer 15

reduction.

Question 16

The loss of electrons is:

Answer 16

oxidation.

Question 17

The total number of electrons lost must be equal to

Answer 17

the total number of electrons gained.

Question 18

Are oxidation and reduction separate processes?

Answer 18

Yes.

Question 19

Do oxidation and reduction occur simultaneously?

Answer 19

Yes.

Question 20

Oxidation-reduction reactions are regularly called:

Answer 20

Redox reactions.

Question 21

Steps for creating a half reaction in an acidic solution:

Answer 21

1. Write the reactants and products.
2. Balance everything other than water and hydrogen.
3. Add water to balance the oxygen atoms.
4. Because its acidic, you have hydrogen atoms available to balance the hydrogen.
5. Add electrons.

Question 22

Tug-of-war analogy and spontaneity:

Answer 22

Each entity pulls on the same electrons and tries to win by pulling the hardest. If one entity wins, a spontaneous reaction occurs.

Question 23

A reducing agent will undergo

Answer 23

oxidation.

Question 24

An oxidizing agent will undergo

Answer 24

reduction.

Question 25

When did the OA and RA terms originate?

Answer 25

During early metallurgy.

Question 26

What was known as the only oxidizing agent early on>

Answer 26

Oxygen.

Question 27

Oxidation and reduction are ______ while OA's and RA's are ______.

Answer 27

Processes; substances.

Question 28

Where is the strongest oxidizing agent on a redox table?

Answer 28

Top left.

Question 29

Where is the strongest reducing agent in a redox table?

Answer 29

Bottom right.

Question 30

What does the redox spontaneity rule state?

Answer 30

A spontaneous reaction only occurs if the OA is above the RA in a redox table.

Question 31

If its an aqueous solution add

Answer 31

water.

Question 32

If its an acidic solution you can add

Answer 32

hydrogen ions.

Question 33

How to predict redox reactions in solution (five step method):

Answer 33

1. List all entities present and classify them as possible OA's or RA's. Don't label spectator ions. 2. Choose the SOA and write its equation (reduction). 3. Choose the SRA and write its equation (oxidation). 4. Balance the electrons then put the equations together to get your net ionic equation. 5. See if its spontaneous using the spontaneity rule.

Question 34

If the table does not have the half-reaction equation, what should you do?

Answer 34

Create one yourself (by doing the thing where you add water, etc.)

Question 35

What is an oxidation state?

Answer 35

The apparent net electric charge that an atom would have if electron pairs in covalent bonds belonged entirely to the more electronegative atom.

Question 36

What is an oxidation number?

Answer 36

A positive or negative number corresponding to the oxidation state assigned to an atom in a covalently bonded entity. Just shows the electrons that can be gained/ given up.

Question 37

All atoms in elements oxidation numbers are:

Answer 37

Zero.

Question 38

Hydrogen in all compounds except hydrides oxidation number:

Answer 38

Positive one.

Question 39

Disproportionation.

Answer 39

Where a substance is both oxidized and reduced at the same time.

Question 40

Oxidation number of oxygen in compounds except peroxides:

Answer 40

Negative two.

Question 41

In H2O2, oxygen's oxidation number is:

Answer 41

Negative one.

Question 42

What is hydrogen's oxidation number when it acts as an anion?

Answer 42

Negative one.

Question 43

Halogen's oxidation number is usually:

Answer 43

Negative one.

Question 44

An increase in oxidation number indicates:

Answer 44

Oxidation.

Question 45

A decrease in oxidation number indicates:

Answer 45

Reduction.

Question 46

Balancing using oxidation numbers steps:

Answer 46

1. Assign oxidation numbers to all of the atoms and ions and note the ones that change. 2. See how many electrons have been travelled. For example, a change from -2 to +4 is 6 e-. 3. Multiply by the subscript. For example, in O2, you would multiply the electrons by two. Within an atom, just look at the thing that changed. For example, in H2S and the sulfur changed, keep the electrons as is. 4. Multiply the electrons of each of the things that changed so that they are equal. This is because the electrons gained and lost should be the same. 5. The numbers you multiplied become the coefficients. for the reactants. 6. Balance everything else based on these numbers. 7. At the end you may need to add water molecules and hydrogen ions if its in an acidic solution.

Question 47

When is the equivalence point reached during titration?

Answer 47

When the exact number of moles of reactants have been used up.

Question 48

When is endpoint reached during titration?

Answer 48

When the next drop of excess reactant is added noted by a colour change.

Question 49

Redox stoichiometry:

Answer 49

Find the SOA and SRA and write those reactions out. Then, convert your solution from mol/L to mols. Then do the mol to mol ratio.