Principles of Chemical Engineering: Module 1 - Units, Dimensions, & Gases

Vocabulary practice flashcards covering systems of units, concentration terms, pressure definitions, gas laws, and equations of state from Module 1: Units, Dimensions, & Gases.

Mass Fraction

The dimensionless ratio of the mass of a specific component to the total mass of the mixture, with numerical values ranging from $0$ to $1$.

Mass Percentage (% w/w)

A mass-based concentration measure calculated as $\frac{\text{mass of component}}{\text{total mass of mixture}} \times 100$, commonly utilized in the food and chemical industries.

Mass-Volume Percent (% w/v)

A concentration measure calculated as $\frac{\text{mass of solute (g)}}{\text{volume of solution (mL)}} \times 100$, used when a solid solute is dissolved in a liquid solvent.

Mass Ratio

In a two-component mixture composed of components $A$ and $B$, the ratio of the mass of component $A$ to the mass of component $B$.

Constancy of Mass (Biotech Formulation)

The principle stating that mass percentages are reliable because mass is immune to temperature changes, whereas liquid volumes expand with increasing temperature and skew volumetric concentration readings.

Mole (mol)

The SI base unit for the amount of substance containing exactly $6.023 \times 10^{23}$ elementary entities (Avogadro's number).

Gram-Atom

A stoichiometric quantity defined as the number of grams of an element divided by the atomic weight of that element.

Gram-Mole

A quantity abbreviated simply as mole ($\text{mol}$ in SI units), defined as the mass of a compound in grams divided by its molecular weight ($\frac{\text{mass in grams}}{\text{molecular weight}}$).

Molarity (M)

The molar concentration expressing the number of moles of solute dissolved per liter of solution ($M = \frac{n}{V}$), having the unit $mol\,dm^{-3}$ or $mol/L$.

Molality (m)

The concentration measurement expressing the number of moles of solute present per $1\,\text{kg}$ of solvent ($m = \frac{n}{W}$), with the unit $mol/kg$.

Normality (N)

A concentration unit expressing the number of gram equivalent weights of solute per liter of solution ($N = \frac{\text{g. equivalent of solute}}{\text{Volume of solution (L)}}$).

Equivalent Weight

The calculated reactive mass of a compound obtained by dividing its molecular weight by its $n$-factor ($\text{Equivalent Weight} = \frac{\text{Molecular Weight}}{n\text{-factor}}$).

n-factor (Acid)

The basicity of an acid, represented by the number of $H^+$ ions that a single molecule of the acid can donate.

n-factor (Base)

The acidity of a base, represented by the number of $OH^-$ ions that a single molecule of the base can donate.

n-factor (Salt)

The magnitude of the total positive or total negative charge represented within the chemical formula of a salt.

n-factor (Redox Reagent)

The total number of electrons gained or lost per molecule of the reagent during an oxidation-reduction reaction.

Mole Fraction

The dimensionless ratio of the number of moles of a single component ($n_i$) to the total number of moles of all components ($n_{\text{total}}$) in a mixture ($x_i = \frac{n_i}{n_{\text{total}}}$).

Mole Percent (Mol%)

The number of moles of a specific component present in $100\,\text{moles}$ of total mixture, equal to its mole fraction multiplied by $100$ ($\text{Mol\%} = x_i \times 100$).

Molar Volume at STP

The constant volume occupied by $1\,\text{mole}$ of an ideal gas at standard temperature ($273.15\,K$) and standard pressure ($1\,\text{atm}$ or $101.325\,\text{kPa}$), equal to $22.414\,L/mol$.

Parts Per Million (ppm)

A unit used for very dilute concentrations denoting $1\,\text{part}$ of solute per $1\,000\,000\,\text{parts}$ of solution ($\frac{1\,\text{g}}{10^6\,\text{g solution}}$, which equals $1\,\text{mg/L}$ in dilute aqueous solutions).

Density (\rho)

The mass per unit volume of a substance ($\rho = \frac{m}{V}$), having the SI unit $kg/m^3$ and common units of $g/cm^3$ or $g/mL$.

Specific Gravity (SG)

The dimensionless ratio of the density of a substance to the density of a reference substance (typically water at $4\,^\circ C$ for liquids).

Baumé Hydrometer

A calibrated glass hydrometer instrument developed by Antoine Baumé used to measure the specific gravity of liquids on the Baumé scale ($^\circ Bé$).

Baumé Scale (°Bé) for Heavy Liquids

The hydrometer scale relation for liquids heavier than water ($SG > 1$), defined by the formula $SG = \frac{145}{145 - ^\circ Bé}$.

Baumé Scale (°Bé) for Light Liquids

The hydrometer scale relation for liquids lighter than water ($SG < 1$), defined by the formula $SG = \frac{140}{130 + ^\circ Bé}$.

API Gravity

A petroleum industry hydrometer scale expressing the relative lightness of petroleum liquids, calculated as $\text{API gravity} = \frac{141.5}{\text{SG at } 60\,^\circ F} - 131.5$, where higher values denote lighter oils.

Gauge Pressure

The pressure value measured frequently by a gauge device relative to the local atmospheric pressure.

Vacuum Pressure

A pressure measurement representing the magnitude by which a system's pressure falls below ambient atmospheric pressure ($\text{Absolute Pressure} = \text{Atmospheric Pressure} - \text{Vacuum Pressure}$).

Absolute Pressure

The total pressure relative to absolute zero pressure (a complete vacuum), calculated as $\text{Atmospheric Pressure} + \text{Gauge Pressure}$.

Ideal Gas Model

A theoretical construct simplifying gas behavior that assumes gas particles possess negligible volume, experience no intermolecular forces, and undergo perfectly elastic collisions.

Boyle's Law

An ideal gas relationship stating that at constant mole quantity ($n$) and temperature ($T$), pressure is inversely proportional to volume ($P \propto \frac{1}{V}$).

Charles's Law

An ideal gas relationship stating that at constant mole quantity ($n$) and pressure ($P$), volume is directly proportional to absolute temperature ($V \propto T$).

Gay-Lussac's Law

An ideal gas relationship stating that at constant mole quantity ($n$) and volume ($V$), pressure is directly proportional to absolute temperature ($P \propto T$).

Avogadro's Law

An ideal gas relationship stating that at constant pressure ($P$) and temperature ($T$), gas volume is directly proportional to the number of moles ($\frac{V_1}{n_1} = \frac{V_2}{n_2}$).

Van der Waals Equation

An equation of state modifying the ideal gas law for real gases, formulated as $\left(P + \frac{an^2}{V^2}\right)(V - nb) = nRT$, where $a$ accounts for intermolecular attraction and $b$ accounts for finite molecular volume.

Compressibility Factor (Z)

A thermodynamic correction factor defined as $Z = \frac{PV}{nRT}$, where $Z = 1$ indicates ideal gas behavior, $Z > 1$ indicates repulsive forces dominate, and $Z < 1$ indicates attractive forces dominate.

Dalton's Law of Partial Pressures

A gas law stating that the total pressure exerted by a mixture of non-reacting gases equals the sum of the partial pressures that each individual gas would exert if it alone occupied the total volume at the same temperature ($P_{\text{total}} = \sum_{i=1}^n p_i$).

Partial Pressure (p_i)

The individual pressure exerted by a single gas in a mixture if it alone occupied the entire container volume at the mixture's temperature, calculated as $p_i = x_i P_{\text{total}}$.

Amagat's Law of Partial Volumes

A law of additive volumes stating that the total volume of an ideal gas mixture equals the sum of the volumes that each constituent gas would occupy individually at the same temperature and pressure ($V_{\text{total}} = \sum v_i$).

Henry's Law

A gas-liquid equilibrium relationship stating that the partial pressure of a dissolved gas in the vapor phase is directly proportional to its mole fraction in the liquid phase ($P_i = H x_i$).

Ideal Gas Density (\rho)

The density of an ideal gas calculated from pressure, molecular weight, temperature, and the universal gas constant using the formula $\rho = \frac{PM}{RT}$.

Average Molecular Weight (M_avg)

The effective molecular weight of a gas mixture determined as the mole-fraction-weighted sum of the molecular weights of its constituents: $M_{\text{avg}} = \sum_{i=1}^n x_i M_i$.