Fundamentals of Engineering Chemistry

Comprehensive practice flashcards defining foundational terms, processes, classifications, equations, and visual diagrams from Fundamentals of Engineering Chemistry, covering water technology, fuels, spectroscopy, polymers, and corrosion.

Global Water Distribution

The estimated breakdown of total Earth water resources: oceans ($97.5\%$), polar ice and glaciers ($1.74\%$), groundwater ($1.7\%$), saline groundwater ($0.94\%$), lakes ($0.013\%$), soil moisture ($0.0012\%$), and rivers ($0.0002\%$).

Hydrogen Bonding in Water

Extensive intermolecular dipole attractions between water molecules that account for water's unusually high viscosity, surface tension, heat of vaporization, and entropy of vaporization.

Open Structure of Ice

A cage-like crystalline framework stabilized by maximum hydrogen bonding that causes solid water to have a lower density than liquid water.

Surface Water

Natural water found on the surface of the earth, including oceans, rivers, lakes, ponds, and streams, fed primarily by precipitation and snowmelt.

Underground Water

Water that seeps through soil down to non-porous rock strata, accessible through springs, dug wells, and sunken tube wells.

Dissolved Impurities

Soluble impurities present in water, including dissolved gases ($O_2$, $CO_2$, $H_2S$) and dissolved mineral salts of calcium, magnesium, iron, sodium, and potassium.

Suspended Impurities

Insoluble matter dispersed in water, categorized as inorganic (clay, silica, oxides of iron and manganese) or organic (oil globules, vegetable matter, and animal matter).

Colloidal Impurities

Finely divided particles in water ranging from finely divided clay and silica to hydrated oxides ($Al(OH)_3$, $Fe(OH)_3$), amino acids, and coloring matter.

Degree of Hardness Scale

Classification of water hardness measured in $mg/L$: Soft ($0-17\,mg/L$), Slightly hard ($17-60\,mg/L$), Moderately hard ($60-120\,mg/L$), Hard ($120-180\,mg/L$), and Very hard ($>180\,mg/L$).

$CaCO_3$ Equivalent

The standard universal unit used to express the concentration of hardness-causing salts, calculated as: $\text{Equivalents of } CaCO_3 = \frac{\text{Weight of salt}}{\text{Equivalent weight of salt}} \times 50$.

Multiplication Factor ($M$)

The stoichiometric factor used to convert the weight of a hardness-producing substance into $CaCO_3$ equivalents, defined as $M = \frac{100}{\text{Molecular weight}} = \frac{50}{\text{Equivalent weight}}$.

Non-Hardness Producing Substances

Soluble salts and compounds present in water—specifically $NaCl$, $KCl$, and urea—that do not react with soap to form insoluble scum and thus do not cause water hardness.

Scum

A white, sticky, insoluble curd formed when soap reacts with dissolved calcium and magnesium ions in hard water, causing significant soap wastage.

Boiler Sludge

A loose, slimy, non-adherent precipitate that remains suspended in boiler water and settles in cooler regions of the boiler system.

Boiler Scale

A hard, dense, adherent coating formed on the inner heating surfaces of boilers that severely reduces thermal conductivity and can cause tube failure.

Caustic Embrittlement

A form of boiler corrosion that occurs when alkaline boiler water concentrates in hairline cracks and rivets, causing caustic cracking of stressed metal.

Priming and Foaming

Boiler operational troubles where priming is the mechanical carryover of liquid water droplets with steam, and foaming is the persistence of stable bubbles on the water surface.

Eriochrome Black T (EBT)

A complexometric azo dye indicator used in EDTA titrations that forms an unstable wine-red complex with $Ca^{2+}$ and $Mg^{2+}$ ions, releasing free blue indicator at the titration endpoint.

Potentiometric Alkalinity Titration Curve

A titration curve of water alkalinity showing distinct inflection points at $pH \approx 8.3$ (phenolphthalein endpoint, neutralizing $OH^-$ and converting $CO_3^{2-}$ to $HCO_3^-$) and $pH \approx 4.5$ (methyl orange endpoint, neutralizing all $HCO_3^-$).

Reverse Osmosis (RO)

A membrane-based desalination process where a hydrostatic pressure greater than osmotic pressure is applied to force water through a semipermeable membrane ($0.0005-0.0000002\,\mu m$ pore size), rejecting dissolved salts.

Electrodialysis (ED)

A water desalination technique that uses an applied direct current electric field to transport cations and anions through alternating cation-exchange membranes (CEM) and anion-exchange membranes (AEM).

Zeolite (Permutit) Process

An ion-exchange water-softening method that passes hard water through a bed of hydrated sodium aluminosilicate ($Na_2O \cdot Al_2O_3 \cdot xSiO_2 \cdot yH_2O$), exchanging $Ca^{2+}$ and $Mg^{2+}$ for $Na^+$.

Calgon Conditioning

An internal boiler water treatment method that uses sodium hexametaphosphate ($(NaPO_3)_6$) to sequester $Ca^{2+}$ ions into a highly soluble complex ($Na_2[Ca_2(PO_3)_6]$), preventing scale precipitation.

Colloidal Conditioning

The addition of organic colloidal substances (such as tannin, kerosene, or agar-agar) to boiler feed water to coat scale-forming crystals and keep them dispersed as non-adherent sludge.

Phosphate Conditioning

The internal treatment of high-pressure boiler feed water with sodium orthophosphates to convert calcium hardness into soft, easily blowdown-removable calcium phosphate precipitate.

Mechanical Deaerator

A thermal conditioning tower equipped with heaters, perforated plates, and a vacuum pump designed to strip dissolved corrosive oxygen and carbon dioxide gases out of boiler feed water.

Break-Point Chlorination

The point of chlorine addition to water where all reducing compounds, chloramines, and chloro-organics are completely destroyed, beyond which further added chlorine remains as free available residual chlorine.

Bomb Calorimeter

A constant-volume laboratory apparatus used to experimentally measure the higher (gross) calorific value of solid and non-volatile liquid fuels by combustion under high oxygen pressure.

Boy's Gas Calorimeter

A steady-flow gas calorimeter apparatus used to determine the gross and net calorific values of gaseous and highly volatile liquid fuels by burning gas at a constant rate while heating flowing water.

Kjeldahl's Method

An analytical digestion and distillation technique used to determine the percentage of nitrogen in coal and organic fuels by converting nitrogen into $(NH_4)_2SO_4$, releasing $NH_3$ with $NaOH$, and titrating into standard acid.

Otto Hoffmann By-Product Oven

A high-temperature regenerative coke oven designed to convert coal into metallurgical coke while capturing by-products such as coal gas, coal tar, ammonia liquor, and benzol.

Cracking

The thermal or catalytic chemical decomposition process that converts high-boiling, high-molecular-weight heavier petroleum fractions into low-boiling, motor-fuel range gasoline hydrocarbons.

Octane Number

A standard rating scale indicating the antiknock quality of gasoline, defined as the volume percentage of isooctane in a blend with $n$-heptane that matches the knock characteristics of the test fuel.

Cetane Number

A measure of the ignition delay and combustion quality of a diesel fuel, defined as the percentage by volume of cetane ($n$-hexadecane) in a mixture with $\alpha$-methylnaphthalene.

Beer-Lambert Law

The governing equation of absorption spectroscopy stating that optical absorbance ($A$) is directly proportional to molar absorptivity ($\varepsilon$), concentration ($c$), and path length ($l$): $A = \varepsilon \cdot c \cdot l$.

Chromophore

An isolated, covalently unsaturated functional group (such as $C=C$, $C=O$, or $-NO_2$) capable of absorbing characteristic ultraviolet or visible electromagnetic radiation.

Auxochrome

A saturated substituent containing non-bonding electrons (such as $-OH$, $-NH_2$, or $-Cl$) that does not absorb UV radiation alone but shifts the absorption of a chromophore to longer wavelengths and increases absorption intensity.

UV-Visible Spectral Shifts

The four characteristic wavelength and intensity shifts: bathochromic (longer $\lambda$), hypsochromic (shorter $\lambda$), hyperchromic (increased $\varepsilon$), and hypochromic (decreased $\varepsilon$).

Bathochromic Shift (Red Shift)

A shift of an absorption band maximum ($\lambda_{\max}$) toward longer wavelengths (lower energy), typically caused by extended conjugation or solvent polarity changes.

Hypsochromic Shift (Blue Shift)

A shift of an absorption band maximum ($\lambda_{\max}$) toward shorter wavelengths (higher energy), often occurring when conjugation is removed or an auxochrome is protonated.

Woodward-Fieser Rules

An empirical calculation method used to predict the absorption wavelength maximum ($\lambda_{\max}$) of conjugated dienes and enones using parent base values ($214\,nm$ for heteroannular, $253\,nm$ for homoannular dienes) plus substituent increments.

Molecular Vibration Modes (IR)

Fundamental vibrational movements observed in infrared spectroscopy, divided into stretching (symmetric and asymmetric) and bending (scissoring, rocking, wagging, and twisting).

Linear Polymer

A polymer architecture composed of long, continuous, straight carbon chains with high packing efficiency, high density, and elevated melting temperatures (e.g., HDPE).

Branched Polymer

A polymer structure characterized by side chains attached to the polymer backbone that inhibit tight packing, resulting in lower density and tensile strength (e.g., LDPE).

Cross-Linked Polymer

A thermosetting polymer structure where individual linear chains are joined across one another by covalent bonds forming a rigid 3D network (e.g., Bakelite).

Ziegler-Natta Catalyst

A coordination polymerization catalyst system consisting of triethylaluminum ($Al(C_2H_5)_3$) and titanium tetrachloride ($TiCl_4$) used to synthesize stereoregular, linear high-density polymers under mild conditions ($6-7\,atm$, $333-343\,K$).

Nylon 6,6

A linear synthetic polyamide formed by the condensation polymerization of adipic acid and hexamethylenediamine under high pressure with the elimination of water.

Bakelite

A rigid, thermosetting phenol-formaldehyde cross-linked network resin formed by step-growth condensation polymerization of phenol and formaldehyde in the presence of an acid or base catalyst.

Biodegradable Polymer

A polymer designed to degrade via microbial enzymatic cleavage into carbon residue, biomass, water, and gases ($CO_2$ under aerobic conditions; $CO_2$ and $CH_4$ under anaerobic conditions).

Electrochemical Corrosion

Wet corrosion that occurs when a metal is exposed to a conducting liquid electrolyte, operating via distinct anodic metal dissolution ($Fe \rightarrow Fe^{2+} + 2e^-$) and cathodic reduction reactions.

Differential Aeration Corrosion

Electrochemical corrosion caused by uneven oxygen exposure on a metal surface, where the poorly oxygenated area becomes anodic and undergoes accelerated corrosion.

Waterline Corrosion

A specific manifestation of differential aeration corrosion where metal located immediately below the water meniscus corrodes anodically due to poor access to atmospheric oxygen relative to the air-exposed cathode.

Pitting Corrosion

A localized form of corrosion characterized by deep cavity or pit formation on a metal surface beneath electrolyte droplets or deposits, driven by small anodic areas surrounded by large cathodic areas.

Galvanic Corrosion

Bimetallic corrosion that occurs when two dissimilar metals in physical or electrical contact are exposed to a common electrolyte, causing preferential accelerated corrosion of the more anodic metal.

Galvanic Series

An experimental electrochemical ranking of metals and alloys based on their measured corrosion potentials in an active electrolyte (such as seawater), predicting anodic versus cathodic behavior upon coupling.

Sacrificial Anodic Protection

A cathodic protection method where a more electrochemically active metal (such as zinc or magnesium) is coupled to a base metal structure (like steel), corroding sacrificially to preserve the structure.

Impressed Current Cathodic Protection

A corrosion mitigation technique that uses an external direct current power source to force electric current from an inert auxiliary anode (graphite or platinum) onto the metal structure to make it entirely cathodic.

Pilling-Bedworth Rule

A criterion predicting whether an oxide film on a metal is protective or non-protective based on the volume ratio of oxide formed to metal consumed ($V_{\text{oxide}} / V_{\text{metal}} \ge 1$ indicates a non-porous, protective film).