Chem Exam #4

Alkaline battery

a dry-cell battery that employs slightly different half-reactions in a basic medium An alkaline battery is a type of primary battery which derives its energy from the reaction between zinc metal and manganese dioxide. Compared with zinc-carbon batteries of the Leclanché cell or zinc chloride types, alkaline batteries have a higher energy density and longer shelf life, yet provide the same voltage.

H2 as a fuel,H2/O2 redox reaction,H2/O2 fuel cell components H2/O2 fuel cell reaction H2/O2 fuel cell automobiles Source for H2

2H2(g) + O2(g) > 2H20(l) There's a 4 electron transfer in this reaction which makes it an oxidation reduction reaction This now becomes 2H2(g) > 4H+(aq) + 4e- This turns into O2(g) +4+(aq)+ 4e- > 2H2O(l) So it has the chemistry to be able to produce electricity (movement of electrons) but under normal conditions the reactants are gases which complicates things Won't work well in a conventional battery However they can produce Fuel Cells which are like batteries but you constantly add redux parts to it-- it's not stored Fuel Cell Diagram Environmentally friendly 2 inlets, 2 gases enter the fuel cell through 2 separate compartments H2 on one side and O2 from the other Anode on the H side and Cathode on the O side Help dissociate the ions from the atoms Hydrogen ions are formed at the anode and electrons are released through the external circuit and passed through the cathode This completes the circuit and as long as you supply hydrogen and oxygen the fuel cell will generate electricity These are being used to recharge automobiles Some cars have been produced that are powered by hydrogen fuel cells 1g of H2(hydrogen) produces 143 kJ

Li ion battery voltage

3.60V/cell.

Uranium as a nuclear fuel

50-85% U 238U 99.27% 235U .72% Uranium 235 is the only uranium that can be used as a fuel Eventually gets converted to pellets You have to get the 235 Uranium to almost 4% to get it to work

Redox reactions

A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction. An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron. Redox reactions are common and vital to some of the basic functions of life, including photosynthesis, respiration, combustion, and corrosion or rusting.

electricity producing reaction

A galvanic (voltaic) cell uses the energy released during a spontaneous redox reaction (ΔG<0) to generate electricity. ... The oxidation half-reaction occurs at one electrode (the anode), and the reduction half-reaction occurs at the other (the cathode).

Uranium enrichment

A process that results in an increase in the amount of the fissionable isotope of uranium in a given mass of uranium. Used mostly for nuclear weapons, naval propulsion, and smaller quantities for research reactors Enriched uranium is a type of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711% of its mass.

Alessandro Volta

Alessandro Volta (1745-1827) Plates of copper and zinc which was a porous material and then soaked in an acidic liquid Showed the effect of electricity One of the first batteries but there were probably more thousands of years prior to this

Alpha decay nuclear reaction

Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.

Oxidation & reduction

Also known as redox; a chemical reaction in which the oxidizing agent is reduced (by losing oxygen) and the reducing agent is oxidized (by gaining oxygen). Oxidation and Reduction reactions occur when electrons are transferred. The molecule that is oxidized loses an electron and the molecule that is reduced gains the electron that was lost by the oxidized molecule. Therefore, oxidation and reduction have to occur together. Oxidation takes place at the anode If electrons flow out of something it's being oxidized (anode) and what it's going towards is the cathode

Beta decay nuclear reaction

Beta decay converts a neutron to a proton and emits a high-energy electron, producing a daughter nucleus with the same mass number as the parent and an atomic number that is higher by 1. Positron emission is the opposite of beta decay and converts a proton to a neutron plus a positron

Cathode material

Cathode materials are comprised of cobalt, nickel and manganese in the crystal structure forming a multi-metal oxide material to which lithium is added.

recharge reaction

Electrodes are made out of lead and lead oxide

Basic components of a nuclear power plant

Fuel. Uranium is the basic fuel Moderator Control rods Coolant Pressure vessel or pressure tubes Steam generator Containment Nuclear power plants in commercial operation or operable

Alkaline Battery Reaction

In an alkaline battery, the anode (negative terminal) is made of zinc powder. This allows for a greater surface area which results in an increased rate of reaction and hence a greater rate of electron flow. The cathode (positive terminal) is composed of manganese dioxide. Alkaline batteries are comparable to zinc-carbon batteries, but the difference is that alkaline batteries use potassium hydroxide (KOH) as an electrolyte rather than ammonium chloride or zinc chloride.

National Carbon Company (NCC)

In the 1890's the National Carbon Company (which become eveready battery co and then energizer) packaged the battery so it became portable Called the columbia dry cell

Nuclear power in VA, the US, the World

Largest uranium ore is in Pittsylvania County, VA Coles Hill Site It's legally blocked from being mined The world's first experience of nuclear energy came during WW2 with the atomic bomb However a controlled reaction can be used as a useful energy source Can nuclear reactions be safely used to produce electricity? Example: Surry Unit 1-1972 Unit 2-1973 PWR 1,598 MW 400,000 homes North Anna Unit 1-1978 Unit 2-1980 PWR 1,806 MW 450,000 homes US, 100 nuclear reactors (about 20% of total electrical output Worldwide, 437 nuclear reactors (about 13% of total electrical output)

Nuclear fission reaction

Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts (lighter nuclei). The fission process often produces free neutrons and photons (in the form of gamma rays), and releases a large amount of energy. Can be spontaneous or initiated Confirmation of E=mc2 1g of coal = about 40 kJ 1 g of 235U= about 90 billion kJ

Nuclear fuel pellets

Nuclear fuel pellets are compounds consisting of center and outside shell where in most world's nuclear reactors, the center contains a brittle uranium blend, and the solid outside shell is made of a metallic alloy containing the element zirconium.

Diesel fuel

Oil is composed of refinery gas with carbon chains 1-4, jet fuel with carbon chains 10-16, diesel and home heating with carbon chains 14-20, and gasoline with carbon chains 7-10 Diesel Fuel and the diesel engine that burns it are unique because the mechanical nature produces a lot more power than a normal internal combustion engine C16H34 = chemical composition of typical diesel Comes from fossil fuels Adds to carbon dioxide in atmosphere

Algae

Photosynthetic components associated with it The lipids in algae are triglycerides Convenient and rapidly growing There are companies making ponds solely to growing algae for biodiesel Hectare is a 100 meters squared Produces a 26,417 gallons

Sieverts and rems

Sieverts (Sv) and Rems 1 sievert (Sv) = 100 rems Sv > rem

Soy beans

Soy beans, canola oil, peanut oil, etc can create these triglycerides

Spent nuclear fuel (nuclear waste)

Spent fuel contains large amounts of uranium, therefore, lots of usable fuel still remains. This makes recycling this fuel possible, and the process of performing separations on the spent fuel to access this uranium and plutonium is known as reprocessing.

Anode material

The anode (or negative electrode) in Lithium-ion battery is typically made up of Graphite, coated on Copper Foil. ... Graphite is commonly used as the active material in negative electrodes mainly because it can reversibly place Lithium-ions between its many layers.

Voltage

The difference in electrical potential energy between two places in a circuit. an electromotive force or potential difference expressed in volts. The high cell voltage of 3.6 volts allows battery pack designs with only one cell

Basic components of a pressurized water nuclear reactor

The reactor coolant system of the pressurized water reactor (PWR) consists of a reactor vessel, steam generators, reactor coolant pumps, a pressurizer, and other elements. These principal components are interconnected by the reactor coolant piping to form a loop configuration.

Triglycerides

an energy-rich compound made up of a single molecule of glycerol and three molecules of fatty acid. Soy beans, canola oil, peanut oil, etc can create these triglycerides Triglycerides are everywhere and plants and animals produce them Triglyceride doesn't burn very well because it's too dense in this form Easy to make and readily available

Chain reaction

chain reaction. In chemistry and physics, a self-sustaining series of reactions. In a chain reaction in a uranium-based nuclear reactor, for example, a single neutron causes the nucleus of a uranium atom to undergo fission. In the process, two or three more neutrons are released.

how a battery works

energy is supplied to the charge to move it from low potential to high potential, then it moves through the circuit and loses energy through each device In a battery, the only place to go is to the cathode. But, the electrolyte keeps the electrons from going straight from the anode to the cathode within the battery. When the circuit is closed (a wire connects the cathode and the anode) the electrons will be able to get to the cathode. In the picture above, the electrons go through the wire, lighting the light bulb along the way. This is one way of describing how electrical potential causes electrons to flow through the circuit

Control rods

neutron-absorbing rods that help control the reaction by limiting the number of free neutrons Control rods are used in nuclear reactors to control the fission rate of uranium and/or plutonium. Their compositions includes chemical elements such as boron, cadmium, silver, and/or indium, that are capable of absorbing many neutrons without themselves fissioning.

Anode & cathode

oxidation happens at the anode reduction happens at the cathode Anode on the H side and Cathode on the O side Help dissociate the ions from the atoms Hydrogen ions are formed at the anode and electrons are released through the external circuit and passed through the cathode A completely charged lithium ion battery the ions go to the anode When you recharge the reaction at the bottom is going backwards and sends the ions back to the cathode on diagram in slides-- anode left, cathode right) Blue balls are lithium ions Cathodes have alternating layers of metal ions (black) and oxygen (green) Oxidation takes place at the anode If electrons flow out of something it's being oxidized (anode) and what it's going towards is the cathode

Biodiesel fuel

type of diesel fuel produced from used cooking oil, vegetable oil, oil squeezed from algae Biodiesel Fuel is fuel based on the fatty acid molecules ** be able to recognize triglyceride in normal and shorthand notation On shorthand the regions in blue represent long carbon chains