Processes and Process Variables

Chapter 3

Mass and VolumeDensity

mass/unit volume g/cm3

Specific Volume volume/ unit mass cm3/g

Specific Gravity Dimensionless

Specific GravityRatio of the density of a substance to a

reference substance at a specific condition

SG=ref

The reference is often the density of water at 4 C 1.000 g/cm3

What Does this mean?

0

0

4

206.0SG

The density of the substance, measured at 20 C, is only 60% of the density of water, measured at 4 C

Flow RateMass flow rate

Mass/timeVolumetric flow rate

Volume/time

V

m

V

m

Flow Rate MeasurementFlowmeter

Rotameter Orifice Meter

Moles and Molecular WeightAtomic WeightMolecular Weightgram-mole lb-mole

Mass and Mole FractionMass fraction

Mole fraction

mass total

A of massAx

moles total

A of molesAy

ConcentrationMass concentration

Mass/volumeMolar concentration

Moles/unit volume of the mixtureMolarity

Molar concentration in gram moles per liter of solution

ppm and ppb

PressureMeasured in psi, pascals, barsHead

Height of a column of water or mercury 1 atm = a head of 33.9 ft of water 1 atm = a head of 760 mm of Hg

Atmospheric PressureAbsolute pressureGauge pressure

Pabsolute = Pgauge + Patmospheric

Pressure MeasurementBourdon GaugeManometerBarometer

We’ve covered all of this in thermodynamics

TemperatureWe’ve been here tooBe sure you can use your calculator to

make conversions between English and SI units

Next time - Homework 3.23 3.30 3.31 3.45 3.50

3.3 3.6 3.7 3.13 3.14 3.16 3.17

Test on Tuesday