chapter 8 oxidation and reduction

redox reaction

Oxidation-reduction reaction, in which one molecule accepts electrons (it becomes reduced) from another molecule (which becomes oxidized). Also called electron transfer.

oxidation and reduction always occur

together

oxidation oxygen atoms

Oxidation electrons

oxidation in terms of hydrogen

oxidation oxidation number

gain of oxygen atoms

loss of electrons

loss of hydrogen

increase oxidation number

reduction oxygen atoms

reduction electrons

reduction in terms of hydrogen

reduction oxidation number

loss of oxygen atoms

gain of electrons

gain of hydrogen

decrease oxidation number

OIL RIG

oxidation is loss,

reduction is gain

whenever oxidation occurs what also happens

reduction must also occur in exactly the same amount

in monoatomic ions the oxidation number is

the number of unit charges on the atom

an atom in elemental form has an oxidation number of

0

oxidation and reduction reactions can produce electricity true or false

true

an atom in a monoatomic ion has an oxidation number equal to

equal to the charge of the ion

hydrogen has oxidation number of

oxygen?

+1

-2

the sum of the oxidation numbers of the atoms in a poly atomic ion equals

the charge of the ion

patina

surface discoloration caused by age and oxidation

the oxidation number for an element is equal to

8 -its group number

oxidizing agent

The electron acceptor in a redox reaction.

reducing agent

electron donor

electrochemical cell

gives an electric current with a steady voltage as a result of an electron transfer reaction

the porous barrier in an electrochemical cell is usally

a salt bridge

electrodes

the two pieces of metal where elctrons are transferred

Anode

Positive electrode, where oxidation occurs.

Cathode

Negative electrode , where reduction occurs.

two half reactions

electrochemical reaction are often split into two

Do metals gain or lose electrons?

to lose

Which quantities are conserved in all redox reactions?

mass onlyboth

charge and mass

charge only

charge and mass

how does an electric eel creat electricity

uses thousands of stacked cells and a difference between potassium and sodium

photochromic glass

glass that changes its optical properties in response to light intensity...

result of oxidation redcution reactions

use silver chloride and copper the silver is susceptible to oxidation and reduction by light

dry cells

an electrochemical cell in which the electrolyte is a paste (graphite powerder)

Battery

dry cell

most important feature of lead storage battery

it can be recharged

In the following reaction that takes place in batteries, which element is being reduced?

Manganese

nickel-cadmium battery

A type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes.

litium ion battery

anode?

cathode?

electrolyte?

graphite

lithium manganese dioxide

mixture of lithium salts

protection of aluminum

Aluminum is more reactive than iron. However, corrosion of aluminum is not a serious problem. Aluminum oxide is very tough and prevents further corrosion.

The black tarnish on silver is

ag2s

Silver tarnishing

oxide on the silver surface

In a reaction, the substance undergoing reduction serves as the A) electron donor. B) proton donor. C) oxidizing agent. D) reducing agent.

oxidizing agent

why does a battery go dead

when one or more of the reactants zinc and MnO2 are used up

Why are TNT explosions so powerful?

TNT decomposes rapidly into several gaseous products.

whya re some batteries rechargeable

they use a reversible redox reaction the starting materials are reformed

How does silver tarnish?

How can the tarnish be removed without the loss of silver?

It is oxidized to silver sulfide.

Use aluminum to reduce the silver sulfide to metallic silver.

rhubarb

used in flow batteries

Which is true about the 12-volt (V) lead storage batteries used in automobiles?

They contain six 2-V cells.

They are filled with hydrochloric acid.

They cannot be recharged.

They contain lead and copper electrodes.

They contain six 2-V cells.

fuel cell

An electrical-chemical device that converts fuel, such as hydrogen, into an electrical current.

the oxidizing agent and reducing agen are supplied continuously to the cell

What is the main active ingredient in common household bleach, also known as chlorine bleach?

NaOCl

Electrolysis

the process in which an electric current is used to produce a chemical reaction, such as the decomposition of water

used to make metals from oxides

The processes of corrosion and explosion undergo oxidation-reduction reactions. Why do explosions tend to be so much more dangerous?

Explosions are often rapid, with huge increases in volume.

In an electrochemical cell, electrons flow from the

anode to cathode

how is a zinc block used to prevent ship rusting

used as a sacrificial anode and gets oxidized instead of iron

what 3 things must be present for corrosion of a metal to happen

water

oxygen

electrolyte

a chemical explosion is what type of reaction

rapid redox reaction

ANFO

ammonium nitrate soaked in fuel oil

exposive mixture

oxygen reacts with nonmetals or metals

both

anaerobic exercise

oxygen is insufficient and leads to weakness

An oxidizing agent that was used in older versions of the Breathalyzer test is

Ozone

powerful oxidizing agent

Which substance is a common reducing agent used in the production of metals from ores?

c (coke)

Metallurgy Reducing Agents

Coke (C) is produced by heating coal to drive off volatile compounds. It is used as a reducing agent in smelting of metals such as tin:

Bleach

oxidizing agents

work by oxidizing carbon

in order to free most metals from compounds we must

the compounds must be reduced

Antioxidants

neutralize free radicals

reducing agents

hydrogen is _____- reducing agent for ____

hydrogen is an excellent reducing agent for both metal and non mental reagents

Reduction in Photography

The silver ions that are exposed to light react with the developer (hydroquinone, C6H4 (OH)2 ) to form metallic silver

A green catalyst is one that

contains earth-abundant elementsmakes reagents react more efficientlydecreases the cost of producing a chemical

hydrogenated

Combined with, treated with, or exposed to hydrogen

catalyst

substance that speeds up the rate of a chemical reaction with out itself being sued up

cellular respiration

important oxidation reduction process where we obtain energy from out food

Photosynthesis

plants synthesize carbohydrates

how can we make hydrogen gas

it can be made by reacting zinc with hydrochloric acid

why are catalysis the key to green and sustainable redox chem

it allows us to avoid using toxic or hazardous reagents like chromium

classify the substances as oxidizing or reducing agents

antioxidants

pure metals

disinfectants

bleaches

antispectices

reducing agents

reducing agents

oxidizing agents

oxidizing agents

oxidizing agents

In addition to carbohydrates, which other substance is a product of photosynthesis?

oxygen