What is the formula for rate constant k?

The rate law for a zero-order reaction is rate = k, where k is the rate constant. In the case of a zero-order reaction, the rate constant k will have units of concentration/time, such as M/s.

How do you calculate the rate of decay?

Suppose N is the size of a population of radioactive atoms at a given time t, and dN is the amount by which the population decreases in time dt; then the rate of change is given by the equation dN/dt = −λN, where λ is the decay constant.

What is rate constant k?

The specific rate constant (k) is the proportionality constant relating the rate of the reaction to the concentrations of reactants. The rate law and the specific rate constant for any chemical reaction must be determined experimentally. The value of the rate constant is temperature dependent.

How do you find half-life decay rate?

The time required for half of the original population of radioactive atoms to decay is called the half-life. The relationship between the half-life, T1/2, and the decay constant is given by T1/2 = 0.693/λ.

How do you find the rate constant using the Arrhenius equation?


  1. Use the Arrhenius Equation: k=Ae−Ea/RT. k is the rate constant, A is the pre-exponential factor, T is temperature and R is gas constant (8.314 J/molK)
  2. Use the equation: ln(k1k2)=−EaR(1T1−1T2)
  3. Use the equation ΔG=ΔH−TΔS.
  4. Use the equation lnk=lnA−EaRT to calculate the activation energy of the forward reaction.
  5. No.

How do you find the rate law equation?

A rate law shows how the rate of a chemical reaction depends on reactant concentration. For a reaction such as aA → products, the rate law generally has the form rate = k[A]ⁿ, where k is a proportionality constant called the rate constant and n is the order of the reaction with respect to A.

What is the formula for calculating half life?

For a zero-order reaction,the mathematical expression that can be employed to determine the half-life is: t1/2 =[R]/2k

  • For a first-order reaction,the half-life is given by: t1/2 = 0.693/k
  • For a second-order reaction,the formula for the half-life of the reaction is: 1/k[R]
  • How do you calculate the number of half lives?

    If a user doesn’t enter in an initial amount, the formula which calculates the half life is, N(t)= e -t ln(2)/t 1/2. Basically it’s the same as the last formula with the exception that the initial amount of the substance, N 0, is removed from the formula.

    What is the equation for half lives?

    Mathematically, the half life can be written in terms of the decay rate: Half-life = – ln(2) / k. The natural logarithm (ln) is a mathematical function that is the inverse to the exponential (e) function. You can find the natural logarithm on a scientific calculator where it will be labelled “ln.”.

    What is the equation for effective half life?

    With the decay constant it is possible to calculate the effective half-life using the formula: t 1 / 2 = ln ⁡ ( 2 ) λ e {\\displaystyle t_{1/2}={\\frac {\\ln(2)}{\\lambda _{e}}}}. The biological decay constant is often approximated as it is more difficult to accurately determine than the physical decay constant.