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Introduction to Process Technology Unit 5 Applied Chemistry Agenda • • • • • • • • • Organic and Inorganic Chemical and Physical Properties Terminology Reactions Chemical Formulas, Calculating Mass Acid, Base, pH Hydrocarbons Other chemical families Review Chemistry in Process Industry • How Chemistry Applies to Process Tech – Turning raw materials into products – Proper management of waste – Understand chemistry concepts that occur during manufacturing process – Understand terminology – Understand concepts to troubleshoot problems and improve quality, efficiency Structure of Matter • Atoms – smallest particle of an element that retains the properties of that element – Protons – positively charged subatomic particle found in the nucleus of an atom – Neutrons – subatomic particle found in the nucleus of an atom that has no charge – Electrons – negatively charged subatomic particle found in orbiting the nucleus of an atom -- Valence Electrons – outermost electrons which provide links for bonding • Ions – charged particles – Anion – atom or group of atoms with negative charge – Cation - atom or group of atoms with positive charge • Molecule – neutral chemically bonded • groups of atoms that act as a unit Isotope – element that has same number of protons but different number of neutrons Structure of Matter (Continued) • Atomic Number – the number of protons in the nucleus of an atom of an element • Atomic Mass (Molecular Weight) – weighted average of the masses of the isotopes of an element predominantly from masses of protons & neutrons • Determining Molecular Weight – – Add all masses of each element. Remember to multiply if more than 1 present. Organic and Inorganic • Chemistry – science that deals with the composition, behavior, and transformation of matter • Organic – carbon based – Hydrocarbon – contains only hydrogen and carbon • Inorganic – no carbons – Such as salts, acids, bases, metals – Many agricultural products Physical Properties • Density – mass (weight) per unit volume • Specific Gravity – comparison of density to that of water for solids and liquids and to air for gases • Hardness – ability of one substance to scratch/mark another • Odor – smell of substance • Color – optical sensation produced by effect of light waves stiking surface Reactivity of a Chemical • The ability of a substance to form new substances under given conditions • A listing of all chemical reactions of a substance and the conditions under which the reactions can occur Types of Bonds • Ionic – metal and non-metal. Electrons are transferred • Covalent – non-metals. Electrons are shared • Metallic – metal to metal. Electrons free flow Terminology • Matter – anything occupying space that has mass • Element – simplest form of matter • Compound – pure substance made up of elements that are chemically combined • Mixture - mixed together, but no chemical reaction • Solution - a homogenous mixture of 2 or more substances in a single phase (usually liquid). Solute and solvent. Terminology (Continued) • Solvent – substance that dissolves • Solute – substance that is dissolved – Solubility : how well solvent dissolves the solute – Insoluable: solute will not dissolve in the solvent • Freezing Point – temp. to change liquid to solid • Melting Point – temp. to change solid to liquid Terminology (Continued) • Boiling Point – When vapor pressure of liquid equals system pressure – As vapor pressure increases, boiling point decreases – As system pressure increases, so does boiling point – The higher the vapor pressure the more easily a material evaporates Terminology (Continued) • Homogenous – Same throughout – Can’t tell one part of mixture from another • Heterogeneous – Different • Equilibrium – Rate of reactants forming products = rate of products forming reactants Chemical Reactions • Chemical Reactions – – – – Endothermic – needs/absorbs heat Exothermic – gives off heat Neutralization – acid + base salt + water Combustion – • fuel + oxygen combustion products + energy + light – Replacement – removes minerals from water Chemical Reactions are Affected By • Heat --- increases molecular activity and reaction rate (rates double with each 10°) • Pressure – slows molecular movement and changes boiling point • Surface Area – solids • Concentration of liquid and gas components • Flow Rates of reactants and products Chemical Reactions • Catalyst – Helps a reaction start, go at a lower temp, or increases rate of reaction – Is not consumed in the reaction Types of Catalysts • Adsorption – solid that attracts and holds reactant molecules so more collisions can occur. Also stretches bonds of reactants making them easier to break, which requires less energy. Types of Catalysts • Intermediate – attaches to reactant molecules and slows it down so collisions can occur • Inhibitor – decreases reaction rate • Poisoned / Spent – no longer functions due to contamination or has been used up – Some can be regenerated Chemical Equations • Like a recipe • Must be balanced (same number of atoms of each element in reactants as products 2H2 + O2 2H2O reactants products Mass Relationships • Allows us to take a balanced equation and use it to determine the actual mass/weight needed for reactants and how much product can be produced Mass Relationships - Steps • Find molecular weight of each element on periodic table (AMUs, but represent grams, pounds, etc.) – Example H = 1.008 O = 16.00 • Multiply by number of atoms (if > 1) – Example H x 2 = 2.016 • Total these up to determine actual weight of entire molecule – Example H2O = 2.016 + 16.00 = 18.016 • Note how reactant mass = product mass Mass Relationships - Steps • Determine how many moles (amounts) of a reactant are needed to produce a set amount of product – Example N2 + 2O2 2NO2 – So you need 1 mole of N2 and 2 moles of O2 to make 2 moles of NO2 Mass Relationships - Steps • Determine the relative volume of reactant or product you have – Example if you only have 16 pounds of O, you only have 0.25 volume (16/64) • Multiply the relative volume by the amount of product you can make – Example – 0.25 x 2NO2 = 0.5 volume of NO2 Mass Relationships - Steps • Multiple the volume you can make by the molecular weight of material – Example – 0.5 volume x 46 * = 23 kg, lbs, tons N= 14.00 kg, lbs, tons O = 16.00 x 2 = 32.00 kg, lbs, tons * 46.00 kg, lbs, tons Material Balances • Method used to determine the exact amount of reactants needed to produce the specified products in the quantity desired • Steps – Determine the weight of each molecule – Ensure reactant total weight equals product total weight – Determine relative number of reactant atoms or ions Percent by Weight Solutions • Weight of solute (material that is dissolved) is taken in relationship to entire solution • 650 pound barrel has 10% catalyst solution – 650 lb x 0.10 (percent as decimal) = 65 lbs Acid, Base and pH • pH – measurement of hydrogen ions in solution • Acid (pH > 0 and < 7) – Sour taste – Vinegar, Hydrocholoric Acid, Hydrofluoric Acid • Base (pH > 7 and < 14) – Bitter taste, slippery • Alkaline • Caustic –pungent odors – Lye, sodium hydroxide, caustic soda • Neutral – pH = 7 • The stronger the acid or base the more hazardous to body tissue and metal Hydrocarbons • Compound that contains both hydrogen and carbon • Fossil fuels – oil & natural gas, and their refined products (gasoline, ethylene) Hydrocarbons • Major groups – Alkanes – single covalent bond (methane, propane, ethane, etc) – Olefins – not naturally occurring. Produced by cracking oil. At least one double bond (hence the high energy when used) • • • • Alkenes – double bonds (ethylene, propylene) Alkyne – triple bonds (acetylene – only one used widely) Cycloalkane – contains a ring or cycle of carbons Aromatic – contains at least one highly unsaturated sixcarbon ring Aromatic Hydrocarbons • Include both hydrocarbons and compounds that cannot be classified as hydrocarbons • Most common - benzene Alcohols • Compounds that contain OH goups connected to an alkyl carbon. – Ethanol – commonly referred to as grain alcohol since often produced from corn, rye, wheat, molasses (from sugar cane), grapes and potatoes. • Becoming popular as gasoline additive or main fuel. Alcohols • Methanol – referred to as wood alcohol, because it was originally derived from wood. – Now produced by subjecting H to CO3 at high temp. in presence of catalyst. – Used as solvent in paints, varnishes, production of formaldehyde, cleaners. Alcohols • Isopropyl Alcohol – most common is rubbing alcohol used externally for cooling skin, disinfect cuts, cosmetic solvent Phenols • Similar to alcohols, but have an OH group connected directly to an aromatic ring. • Used in antiseptics, dyes, aspirin, and at one time throat lozenges Ethylene Glycol • Highly reactive ethylene oxide is reacted with water • Commonly used as antifreeze in vehicle radiators because of unique abiltiy to lower freezing point of water. • Also has higher boiling point than water so better suited to high and low temp. variations due weather extremes. • Because of toxicity when ingested there is a move to switch to less toxic propylene glycol – which many countries in Europe have already done Applied Concepts • Distillation – separation of various fractions in a mixture by individual boiling points • Reactors – designed to break or make chemical bonds which changes reactants into products Applied Concepts • Catalytic Cracking – splits side stream of fractionating column into smaller, more useful molecules – for example, kerosene into hexane and hexene • Hydrocracking – process used to boost gasoline yield • Alkylation – uses a reactor to make one large molecule out of smaller ones. For example isobutane and olefins into high octane alkylates Review • List importance of applied chemistry to process technicians • Re-write all vocabulary words and their definitions • Understand difference between the following: – Organic and inorganic – Endothermic and exothermic – Acids and bases • Define the 4 basic chemical reactions most common to process industry Work • Read CAPT Chapter 11 (pages 158 – 169) – Do questions 1 – 13 on pages 170 & 171) • Read Thomas Chapter 13 (pages 281 – 302 – Do questions 1 – 21 on page 303 • Module 5, Exercise 1 – Chemistry Supplement • Major Grade • In class example worked by group Independent Project • Internet or literature search • Write a paper on the importance of chemistry to 2 different process industries • List raw materials, products • List what chemical reactions, terms apply • Identify associated safety and environmental measures and/or concerns