Mass and Energy Balance
What is a process
Operations that involve a physical or chemical change.
What is an input
Materials that enter the process (feed)
What is an output
Materials that leave the process (product)
Types of process variables
Mass and Volume
What is density
Mass per unit volume
What are the units of density
grams cubic centimeter, kilogram cubic centimeter, pound mass cubic feet
What is specific volume
volume per unit mass
Units of specific gravity
cubic centimeter grams, cubic centimeter kilogram, cubic feet pound mass
How density and specific gravity relates
Are conversion factors that relate mass and volume
Densities of pure solids or liquid change in T or P
They do not change very much.
Densities of gases change in T or P
They do change often
Definition of specific gravity
Ratio of the density (P) of the material to the density of a reference material (water)
What is mass and volumetric rate
Rate at which a material is transported through a process line.
Unit of mass flow rate
kilograms per second
Unit of volumetric flow rate
cubic meters per second
How mass and volumetric flow rate are related
By the density of fluid.
What is chemical composition
Refers to mixtures. Physical properties depend strongly on the content of each component (composition).