chemistry engineering

8/4/2019 Chemistry Engineering

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JESSICA TRINIDAD GARCIA


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Absorbance

Defined as -log(1-) = log(1/), where isthe absorptance and the transmittance of amedium through which a light beam passes.


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Acid

A substance that yields an H+ ion whenit dissociates in solution, resulting in apH


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Adiabatic process

A thermodynamic process in which noheat enters or leaves the system.


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Alcohols

Compounds in which a hydroxy group, -OH, is attached to a saturated carbonatom.


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Base

A substance that yields an OH ionwhen it dissociates in solution, resultingin a pH>7.


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Buffer

A solution designed to maintain aconstant pH when small amounts of astrong acid or base are added.


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Calorie

A non-SI unit of energy, originallydefined as the heat required to raise thetemperature of 1 g of water by 1C.

Several calories of slightly differentvalues have been used.


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Cation

A positively charged atomic or molecularparticle.


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Catalyst

A substance that participates in a particularchemical reaction and thereby increases itsrate but without a net change in the amount

of that substance in the system.


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Colloid

Molecules or polymolecular particlesdispersed in a medium that have, atleast in one direction, a dimension

roughly between 1 nm and 1 m.


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Diamagnetism

A type of magnetism characterized by anegative magnetic susceptibility, so thatthe material, when placed in an external

magnetic field, becomes weaklymagnetized in the direction opposite tothe field.


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Electronegativity

A parameter originally introduced byPauling which describes, on a relativebasis, the power of an atom or group of

atoms to attract electrons from the samemolecular entity.


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Isomers

In chemistry, compounds that haveidentical molecular formulas but differ inthe nature or sequence of bonding of

their atoms or in the arrangement oftheir atoms in space.


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Isotopes

Two or more nuclides with the sameatomic number Z but different massnumber A.


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Molar mass

The mass of one mole of a substance. Itis normally expressed in units of g/mol,in which case its numerical value is

identical with the molecular weight


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Nucleon

A collective term for the proton andneutron.


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Semiconductor

A material in which the highest occupiedenergy band (valence band) is completelyfilled with electrons at T =0 K, and the

energy gap to the next highest band(conduction band) ranges from 0 to 4 or 5eV.


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Salt

An ionic compound formed by thereaction of an acid and a base.


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Silicones

Polymeric or oligomeric siloxanes,usually considered unbranched.


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Viscosity

The proportionality factor between sheerrate and sheer stress.


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Plant

A group of processing units. Within thiscontext, it is the entire processing facility,typically too large to be the focus of a single

plant-performance analysis.


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Model

Qualitative or quantitative relationshipbetween operating specifications andproducts.


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Equipment boundary

Limit in equipment operation. This could refer todesign limits such as operating pressure andtemperature. More often, the concern of theplant-performance analyst is the upper and

lower operating limits for the equipment. Theseboundaries typically describe an operatingrange beyond which the equipmentperformance deteriorates markedly.


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Accuracy

Proximity of the measurements to actualvalues. Data frequently contain bias, adeviation between the measurement

and the actual value. The smaller thedeviation, the greater the accuracy.


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Fault detection

Process of identifying deteriorating unitoperating performance. Examples areinstrument failure, increased energy

consumption, and increased catalystusage.


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Equipment constraints

Limits beyond which the equipmentcannot be operated, either due to designor operating boundaries.


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Measurements

Plant information. These provide a windowinto the operation. They may consist ofroutinely acquired information such as that

recorded by automatic control systems orrecorded on shift logs, or they may consist ofnonroutine information acquired as part of aplant test.


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Identification

Procedure for developing hypotheses anddetermining critical measurements.Identification requires an understanding of

the intent of the process and intent of theplant-performance analysis to be conducted


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Gross error

Extreme systematic error in a measurement.The bias or systematic error is sufficientlylarge to distort the reconciliation and model

development conclusions. Gross errors arefrequently identified during rectification.Validation steps also are used to identifygross errors in measurements.


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Interpretation

Procedure for using the plant measurementsor adjustments thereof to troubleshoot,detect faults, develop a plant model, or

estimate parameters.

chemistry engineering

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