Presentation on theme: "Unit 4: Industry Debate: Chemical Plant in Riverwood? - EKS Nitrogen Products Company OR - WYE Battery Technology Corporation."— Presentation transcript:
Unit 4: Industry Debate: Chemical Plant in Riverwood? - EKS Nitrogen Products Company OR - WYE Battery Technology Corporation
EKS fact: 3 million tons of ammonia, NH 3, and 1.5 million tons of nitric acid are produced annually mainly for manufacturing fertilizers.
Background on EKS Nitrogen Products PotassiumPhosphorousNitrogen Key components in Fertilizer
Commercial 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) N H 2 ⇌ 2 NH 3 (ΔH = −92.22 kJ·mol −1 )mol Future techniques could include genetic engineering - plants would contain genes that will direct the production of nitrogen fixing enzymes.
2 main reasons rxns occur: (the driving forces ) 1. Energy Spread 2. Matter spread this can occur in opposition - ex: table salt dissolving in water. RXN RATES: COLLISION THEORY 1. COLLISION FREQUENCY 2. ORIENTATION 3. ACTIVATION ENERGY WHAT DETERMINES THE SPEED OF THE RXN?? Chemical Kinetics – study of how fast chemical reactions occur
ATOMS, IONS, AND MOLECULES CAN REACT TO FORM PRODUCTS WHEN THEY COLLIDE, PROVIDED THE PARTICLES HAVE ENOUGH KINETIC ENERGY. Collision Theory: Why does a tomato take 3 weeks to ripen versus forming fossil fuels such as oil takes millions of years?
Collision 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 collide 2. it increases the KE of the particles so that more are in the activation energy level.
2. orientation: refers to the position of the particles relative to each other (the geometry) at the time of collision
Activation Energy, E a - the minimum KE that reacting molecules must have in order to react What is the E a when the reaction is instantaneously spontaneous? What is the E a when the reaction is slow to start? High or low?
Summary: factors influencing rxn rates: 1.Collision frequency 2.Orientation of the molecules 3.Activation Energy
effect 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****
Practice: 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?
What is chemical equilibrium?chemical equilibrium Type of reaction: Macroscopic level definition: Molecular level definition:
Let’s clarify equilibrium If a reaction is at equilibrium, does that mean there are equal amounts of products and reactants?
SHIFTING THE EQUILIBRIUM
Rate versus Amount
Applying kinetics/equilibrium to Haber-Bocsh Process N H 2 ⇌ 2 NH 3 (ΔH = −92.22 kJ·mol −1 )mol Reversible Reaction with a high activation energy How do chemical engineers at EKS overcome these obstacles to produce ammonia? Fast and produce more product!
Le 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 change Pressure change Concentration: Reactants or products added or removed
Le 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 pressure change the temperature
Using Le Chatelier’s principle: How could you increase yield of these reactions? CO 2 (g) + H 2 (g) CO(g) + H 2 O(g), endothermic 4CuO(s) 2Cu 2 O(s) + O 2 (g) 2SO 2 (g) + O 2 (g) 2SO 3 (g), - H
From raw materials to products Waste – is anything that is not the desired product Green Chemistry ples.htm
How do batteries work? What is the chemistry involved in a battery?
Voltaic Cells Voltaic 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 wire Salt bridge cathode and anode Alessandro Volta - invented the first voltaic cell (1800)
Electrical Potential – Voltaic Cell – Electrode – Electric Current - Salt Bridge -
How 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 potential The differing tendency of metals to lose electrons allows an oxidation -reduction to generate electricity!
A battery consists of a number of voltaic cells. Here’s an example of a single “wet” cell. Zinc is oxidized. Copper is reduced. Sulfate
Cathode (half-cell) Copper will be reduced. Consonants.
Anode (half-cell) Zinc will oxidize Vowels.
Use oxidation potential series to determine electric potential (“voltage”) of this cell. Zn Zn e - (3.63 V)Cu 2+ Cu + 2e - (-2.53 V) Difference in electric potential is 1.10 V. Zinc is oxidized. Copper is reduced. Sulfate
Batteries - dry voltaic cell Converting Chemical energy --> electrical energy. anode = zinc cathode = graphite rod salt bridge is replaced by the MnO 2 paste - it keeps the contents of the cell from freely mixing. Voltaic Pile
How 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.
How do car batteries work? How they work!
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 release before 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.
Lead and lead-oxide strips are placed in sulfuric acid. What is oxidized? Which is reduced? Car Battery
Lead and lead-oxide strips are placed in sulfuric acid. What voltage is generated? Lead is oxidized. Lead oxide is reduced. Car Battery
Lead and lead-oxide strips are placed in sulfuric acid. What voltage is generated? 3.22 V V = 2.04 V Lead is oxidized. Lead oxide is reduced. Car Battery
Lithium Ion Batteries Anode – carbon Cathode - lithium compound ex: LiCoO 2 LiNiMnCoO 2 (NMC) LiFePO 4 Electrolyte – organic solvent and a Lithium salt How it works: lithium ions move from the carbon anode through the electrolyte to the cathode where they attach.
Life Cycle of Batteries Recycling Car Batteries Lithium Ion Rechargable