What is meant by steady state approximation?
The steady state approximation is a method used to estimate the overall reaction rate of a multi-step reaction. It assumes that the rate of change of intermediate concentration in a multi-step reaction are constant.
What is the pre equilibrium approximation?
The pre-equilibrium approximation is used to find the rate law for a reaction with a fast and reversible initial step. In this method, we first write the rate law based on the slow (rate-determining) step.
What is pseudo steady state approximation?
Pseudo-steady state and the approximation technique
This approximation of the flow problem is obtained from Darcy’s law, the equation of continuity for fluid of small, constant compressibility and constant viscosity as in Collins. Consistent units are assumed in all equations.
How do you use steady state approximation?
Make appropriate assumptions so that the derived rate law agrees with the observed rate law. Give expressions for the producing rate of an intermediate. Give expressions for the consuming rate of an intermediate. Express concentration of intermediate in terms of concentration of reactants.
What is an example of steady state?
A simple example of such a system is the case of a bathtub with the tap running but with the drain unplugged: after a certain time, the water flows in and out at the same rate, so the water level (the state variable Volume) stabilizes and the system is in a steady state.
What is another word for steady state?
In this page you can discover 13 synonyms, antonyms, idiomatic expressions, and related words for steady-state, like: quasi-static, , adiabatic, oscillatory, non-ideal, temperature-dependent, equilibrium, equilibration, , maximal and diffusive.
What is equilibrium assumption?
In order to derive this expression, one assumes that the rate of the forward reaction is equal to the rate of the reverse reaction for the initial step in the mechanism.
What is partial equilibrium approximation?
The assumption of partial equilibrium removes short time scales from the problem and leads to a reduction in the number of independent thermodynamic variables. Making use of a fundamental property of equilibrium reactions, a general formulation for partial chemical equilibrium in complex reaction systems is obtained.
What is pseudo steady state hypothesis?
The assumption that the net rate of reaction is zero is called the Pseudo Steady State Hypothesis (PSSH) The active intermediates reside in the trough of the reaction coordinate as shown below for in the reaction studied by Zewoil.
What do you mean by quasi steady state?
A situation that is changing slowly enough that it can be considered to be constant. For example, atmospheric turbulence has a fast response time, while the atmospheric boundary layer depth that controls the turbulence grows with a slower timescale.
Why is steady state approximation useful?
If the steady state approximation is applied, then the derivative of the concentration of the intermediate is set to zero. This reduces the second differential equation to an algebraic equation which is much easier to solve.
Why is steady state important?
Understanding steady state is also important for choosing the right dose and dosing interval to achieve a desired steady-state concentration—and for determining how long it will take for therapeutic exposures to be achieved during repeat or continuous dosing, since it might take several doses for a drug to achieve …
What is the opposite of steady state?
Noun. Opposite of unvarying condition. nonequilibrium. unstable state.
What is meant by stable state?
Thus, the state of relatively stable or metastable equilibrium is defined as the state in which a system remains for a long period of time, and any slight disturbance causing the system to deviate from the metastable state does not result in the system passing into another state.
What is a quasi equilibrium approximation?
The quasi-equilibrium assumption is often used to simplify the analysis of reaction diffusion problems, including those that arise in drug dissolution and ionization processes. This approximation often makes the governing equations tractable, and analytical solutions may then be obtained.
What is difference between partial equilibrium and general equilibrium?
Partial equilibrium means an equilibrium derived by considering the effect of only two variables at a time. All other variables are considered to be constant. General equilibrium means an equilibrium which is derived by considering the effect of many variables at a time.
What is quasi steady state assumption?
The quasi-steady-state assumption (QSSA) of biochemistry is studied as an approximation that is important in itself and also that exemplifies an approach to ODE systems with an initial fast transient. Simple estimates of the two relevant time scales of the underlying problem are made.
What is the long chain approximation?
A long chain approximation is presented for the analysis of free radical mechanisms. This permits the calculation of relative concentrations on the basis of the chain propagation reactions alone and is valid for large chain lengths.
What do you mean by quasi steady state Mcq?
Explanation: The total biomass in the culture (X) increases with time, cell concentration (x) remains virtually constant, that is dx/dt ≅ 0 and therefore μ ≅ D. This situation is termed as a quasi steady state.
Is fed batch steady state?
A fed batch culture may reach a “quasi-steady state” in which the specific growth rate (μh−1) virtually = the dilution rate, that is, the ratio of medium flow rate to culture volume. In a quasi-steady state the specific growth rate gradually decreases.
How does steady state approximation differ from equilibrium approximation?
The steady state method can only be used if the first step of a reaction is much slower than the second step, whereas the pre-equilibrium approximation requires the first step to be faster. These opposing conditions prevent the two methods from being interchangeable.
What is another name for steady state?
In fiber optics, “steady state” is a synonym for equilibrium mode distribution.
What’s another word for steady state?
What is the difference between stable and metastable?
The distinction between stable and metastable equilibrium is generally that the stable equilibrium state is “truly unchanging”, or unchanging given in- definite time, whereas the metastable state may be changing, but too slowly to be observed (see Quota- tions).
What are the 3 types of equilibrium?
There are three types of equilibrium: stable, unstable, and neutral. Figures throughout this module illustrate various examples.