What is the principle behind material balance?
Analysis & Theory
Material balance is based on the law of conservation of mass.
In a steady-state process with no chemical reaction, what is true?
Analysis & Theory
At steady state and no reaction, input equals output.
Which component is needed in a material balance involving a chemical reaction?
A
Stoichiometric coefficients
D
Reaction temperature only
Analysis & Theory
Stoichiometry helps determine reactant and product relationships.
What is 'generation' in material balance?
A
Addition of fresh reactants
B
Production of species by reaction
D
Mass input from the environment
Analysis & Theory
Generation refers to the creation of mass due to chemical reaction.
What is the general mass balance equation with reaction?
B
Input = Output + Generation - Consumption
D
Input = Output + Heat Loss
Analysis & Theory
With reaction: Input - Output + Generation - Consumption = Accumulation.
In a batch process without chemical reaction, the material balance becomes:
C
Input = Output + Generation
Analysis & Theory
In batch non-reactive systems, mass is stored, hence input = accumulation.
What does 'steady-state' imply in material balances?
B
No accumulation in the system
C
Reactants are fully consumed
Analysis & Theory
Steady-state means accumulation term is zero.
Which of the following processes involves material balances *with* reaction?
Analysis & Theory
Neutralization is a chemical reaction.
Which process is considered non-reactive in terms of material balance?
Analysis & Theory
Leaching is a physical separation process without chemical change.
In the presence of reaction, which terms must be considered in the balance?
B
Input, output, generation, consumption
C
Only generation and consumption
Analysis & Theory
Material balance with reaction includes generation and consumption.
A system has input = 100 kg/hr, output = 80 kg/hr, what is the accumulation?
Analysis & Theory
Accumulation = Input - Output = 100 - 80 = 20 kg/hr.
Which equation is used for a component material balance?
A
Total mass = volume × density
B
Component in - Component out + Generation - Consumption = Accumulation
C
Input = Output + Work done
D
Mass = moles × gas constant × temperature
Analysis & Theory
Component balance accounts for that specific species in the system.
In a reactive system, which term is often zero in steady-state continuous operation?
Analysis & Theory
At steady state, accumulation = 0.
If a component is inert in a process, what does this mean?
C
It does not react at all
D
It accelerates the reaction
Analysis & Theory
An inert component is not involved in the chemical reaction.
Why are mole balances used instead of mass balances in some processes?
A
Moles are easier to measure
B
Reactions are written in moles
C
Mass changes during reactions
D
Moles are constant at high temperatures
Analysis & Theory
Chemical reactions are balanced based on mole quantities, not mass.
What is the 'extent of reaction' used for in material balances?
A
To calculate molar volumes
B
To track how far a reaction has proceeded
D
To change fluid velocity
Analysis & Theory
Extent of reaction quantifies the progress of the reaction in mole terms.
Which component balance is identical to total balance in single-component systems?
Analysis & Theory
For single-component systems, component and total balances are the same.
In a non-reactive separator, the total material balance would be:
B
Input = Output + Accumulation
Analysis & Theory
No reaction or accumulation means mass in = mass out.
Which is NOT a step in performing a material balance with reaction?
A
Draw process flow diagram
B
Label known and unknown variables
C
Write balanced chemical equations
Analysis & Theory
Stoichiometry is essential in a reactive system.
In a distillation column (non-reactive), the key balances include:
B
Component and total material balances
Analysis & Theory
Distillation involves physical separation, needing component and total balances.