Presentation on theme: "Unit 4: Industry Debate: Chemical Plant in Riverwood?"— Presentation transcript:
1Unit 4: Industry Debate: Chemical Plant in Riverwood? - EKS Nitrogen Products CompanyOR- WYE Battery Technology Corporation
2Figure 5.11 – Page 515Legumes have nitrogen fixing bacteria on their roots increase amt of usuable nitrogen for plants in the soil
3Figure 5.3 – Page 507EKS fact: 3 million tons of ammonia, NH3, and 1.5 million tons of nitric acid are produced annually mainly for manufacturing fertilizers.
4Background on EKS Nitrogen Products PotassiumPhosphorousNitrogenAmmonium, potassium and Iron cationsNitrate, phosphate, and sulfate anionsKey components in Fertilizer
5Figure 5.8 – Page 513Ammonia get used directly to synthesize amino acids. Nitrate ions are also used to synthesize amino acidsPlants with nitrogen-fixing bacteria take N2 from air and convert it to a “plant usable form” NH3 or NH4
7Commercial Production of Ammonia “world production of commercial fertilizer has increased dramatically over the past 65 years” (US annual ~ 20 BILLION pounds of ammonia)Haber-Bosch process current method for production of ammonia ( Germany)N2 + 3 H2 ⇌ 2 NH3 (ΔH = −92.22 kJ·mol−1)Future techniques could include genetic engineering - plants would contain genes that will direct the production of nitrogen fixing enzymes.“Scientists are exploring biological methods for making atmospheric nitro-gen more available to plants. These methods include engineering some microorganisms and plants to contain genes that will direct the production of nitrogen fixing enzymes – thus producing their own nitrogen-based fertilizers” –pg.514
92 main reasons rxns occur: (the driving forces) WHAT DETERMINES THE SPEED OF THE RXN??1. Energy Spread2. Matter spreadthis can occur in opposition - ex: table salt dissolving in water.RXN RATES: COLLISION THEORY1. COLLISION FREQUENCY2. ORIENTATION3. ACTIVATION ENERGYChemical Kinetics – study of how fast chemical reactions occur
10Collision Theory: Why does a tomato take 3 weeks to ripen versus Atoms, ions, and molecules can react to form products when they collide, provided the particles have enough Kinetic energy.Why does a tomato take 3 weeks to ripen versusforming fossil fuels such as oil takes millions of years?
11Collision frequency (concentration & temp): The effect of TEMPERATURE on rxn rates:As temp , the rate of rxn(typically the rate of rxn doubles for every 10 C rise in temp)WHY?1. Heating will cause the particles to move faster –> this increases the frequency in which particles will collide2. it increases the KE of the particles so that more are in the activation energy level.
122. orientation: refers to the position of the particles relative to each other (the geometry) at the time of collision
13Activation Energy, Ea - the minimum KE that reacting molecules must have in order to react High or low?What is the Ea when the reaction is instantaneously spontaneous?What is the Ea when the reaction is slow to start?
14Summary: factors influencing rxn rates: Collision frequencyOrientation of the moleculesActivation Energy
15effect of catalyst on rxn rates Catalyst: speeds up the rate of the rxn without being consumed by the reaction.Ex: HCl (not always)-zinc iodide lab –acidified water,Enzymes (catalysts in living systems)****They work by lowering the activation energy****
18Practice:A lump of sugar can be held in your hand (at body temp) without it reacting with oxygen. Holding a match under the lump of sugar does not ignite it. If the sugar is swallowed and metabolized by your body, carbon dioxide and water are produced, and energy is released.A. What does the info tell us about the activation energy for the oxidation of sucrose?B. How could it be possible for the oxidation of sugar to occur in the body at 37C but not when held in the hand at same temp or heated with a flame?C. Is this an exothermic or endothermic rxn?
19What is chemical equilibrium? Type of reaction:Macroscopic level definition:Molecular level definition:Chemical equilibrium – when rates of the forward and reverse reaction are equal.Dynamic equilibrium – both forward and reverse reactions continue to proceed but because their rates are equal, no net change occurs in the concentration of the reaction components.Equilibrium position – lies to the left or lies to right
20Let’s clarify equilibrium If a reaction is at equilibrium, does that mean there are equal amounts of products and reactants?
23Applying kinetics/equilibrium to Haber-Bocsh Process N2 + 3 H2 ⇌ 2 NH3 (ΔH = −92.22 kJ·mol−1)Reversible Reaction with a high activation energyHow do chemical engineers at EKS overcome these obstacles to produce ammonia?Fast and produce more product!Re-write equation with Energy as a product. Look at PE diagram for this reaction (fairly large activation energy required)
24Le Chatelier’s Principle LeChatlier’s principle – when a system in equilibrium is disturbed the system will shift in composition until equilibrium has been re-established.Examples of “disturbances” that can cause a shift:Temperature changePressure changeConcentration: Reactants or products added or removed
25Le Chatelier’s Principle, con’t. Therefore, there are 4 ways to increase the yield of a product in a gaseous equilibrium reaction:remove product(s)add more reactant(s)change the volume of the container in order to change gas pressurechange the temperature
26Using Le Chatelier’s principle: How could you increase yield of these reactions?CO2(g) + H2(g) CO(g) + H2O(g), endothermic4CuO(s) Cu2O(s) + O2(g)2SO2(g) + O2(g) SO3(g), -DH
27From raw materials to products Waste – is anything that is not the desired productGreen Chemistryples.htm
28How do batteries work?What is the chemistry involved in a battery?
29Voltaic CellsVoltaic cell - an electrochemical cell that uses a spontaneous chemical rxn to generate an electric current.Components of a voltaic cell:2 half-cells connected by a wireSalt bridgecathode and anodeAlessandro Volta - inventedthe first voltaic cell (1800)
30Electrical Potential – Voltaic Cell –Electrode –Electric Current -Salt Bridge -Electrical Potential (Volts) – the tendency for electrical charge to move thorough an electrochemical cellVoltaic Cell –Electrode – a strip of metal or other conductor serving as a contact between an ionic solution and the external circuit in an electrochemical cell.Electric Current – the flow of electrons
33How does a voltaic cell work spontaneously? When you connect 2 metals from different positions on the activity series - it creates a electrical potential energy difference b/w the metals.The greater the activity b/w the two metals, the greater the electrical potentialThe differing tendency of metals to lose electrons allows an oxidation -reduction to generate electricity!
34A battery consists of a number of voltaic cells. Here’s an example of a single “wet” cell.SulfateCopper is reduced.Zinc is oxidized.
35Cathode(half-cell)Copper will be reduced.Consonants.
38Zn Zn2+ + 2e- (3.63 V) Cu2+ Cu + 2e- (-2.53 V) Use oxidation potential series to determine electric potential (“voltage”) of this cell.Zn Zn2+ + 2e- (3.63 V) Cu2+ Cu + 2e- (-2.53 V)Difference in electric potential is 1.10 V.SulfateCopper is reduced.Zinc is oxidized.
39Batteries - dry voltaic cell Converting Chemical energy --> electrical energy.anode = zinccathode = graphite rodsalt bridge is replaced by the MnO2 paste - it keeps the contents of the cell from freely mixing.Voltaic Pile
40How Batteries Work Common battery chemistries include: Zinc-carbon battery: common in many inexpensive AAA, AA, C and D dry cell batteries. The anode is zinc, the cathode is manganese dioxide, and the electrolyte is ammonium chloride or zinc chloride.Alkaline battery: common in AA, C and D dry cell batteries. The cathode is composed of a manganese dioxide mixture, while the anode is a zinc powder.Lithium-ion battery (rechargeable):, such as cell phones, digital cameras and even electric cars. A variety of substances are used in lithium batteries, such as lithium cobalt oxide cathode and a carbon anode.Lead-acid battery (rechargeable): This is the chemistry used in a typical car battery. The electrodes are usually made of lead dioxide and metallic lead, while the electrolyte is a sulfuric acid solution.
42A 9 V battery consists of six 1 A 9 V battery consists of six 1.5 V batteries (like AAA batteries) wired in series.Capacity refers to how many electrons the series redox reactions will releasebefore no more reactants remain. We will measure this quantity in MOLES of electrons. It is related to the lifetime of the battery.Voltage is proportional to the amount of potential energy each electron gains in the reaction. It is related to the power the battery can provide.
43Lead and lead-oxide strips are placed in sulfuric acid Lead and lead-oxide strips are placed in sulfuric acid. What is oxidized? Which is reduced?Car Battery
44Lead and lead-oxide strips are placed in sulfuric acid Lead and lead-oxide strips are placed in sulfuric acid. What voltage is generated?Lead is oxidized.Lead oxide is reduced.Car Battery
45Lead and lead-oxide strips are placed in sulfuric acid Lead and lead-oxide strips are placed in sulfuric acid. What voltage is generated? V V = 2.04 VLead is oxidized.Lead oxide is reduced.Car Battery
46Lithium Ion BatteriesAnode – carbonCathode - lithium compoundex: LiCoO2LiNiMnCoO2 (NMC) LiFePO4Electrolyte – organic solvent and a Lithium saltHow it works: lithium ions move from the carbon anode through the electrolyte to the cathode where they attach.
47Life Cycle of Batteries Recycling Car BatteriesLithium Ion Rechargable