How to calculate half life of a first order reaction

Asked by admin @ 07/11/2021 in Chemistry viewed by 319 People

What is the half-life of a first-order reaction if it takes 4.4 x 102 seconds for the concentration to decrease from 0.50 M to 0.20 M? 2.5 x 102 s 3.3 x 102s 1.6s 21 s 27 s

Answered by admin @ 07/11/2021

Answer: The half-life of a first-order reaction is, $3.3\times 10^2s$

Explanation:

All the radioactive reactions follows first order kinetics.

Rate law expression for first order kinetics is given by the equation:

$k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}$

where,

k = rate constant = ?

t = time taken = 440 s

$[A_o]$ = initial amount of the reactant = 0.50 M

[A] = left amount = 0.20 M

Putting values in above equation, we get:

$k=\frac{2.303}{440s}\log\frac{0.50}{0.20}$

$k=2.083\times 10^{-3}s^{-1}$

The equation used to calculate half life for first order kinetics:

$t_{1/2}=\frac{0.693}{k}$

Putting values in this equation, we get:

$t_{1/2}=\frac{0.693}{2.083\times 10^{-3}s^{-1}}=332.69s=3.3\times 10^2s$

Therefore, the half-life of a first-order reaction is, $3.3\times 10^2s$

The rate of first order reaction is 0.04

Asked by admin @ 25/08/2021 in Chemistry viewed by 311 persons

The rate of first order reaction is 0.04 mol per litre sec at 10 min and 0.03 mol per litre sec at 20 min after initiation find half life of …

For a first order reaction it takes 5 minutes

Asked by admin @ 23/08/2021 in Chemistry viewed by 305 persons

For first order reaction it take 5 minutes to initial conc. Of 0.6 m to become 0.4 m how long will it take to become 0.3 m.

The rate of a first order reaction is 1.5

Asked by admin @ 17/08/2021 in Chemistry viewed by 316 persons

The rate of first order reaction is 1.5*10^-2 molL-1/min-1 at 0.5 m .concentration of the reactant .the half life of the reaction is

A first order reaction has a rate constant 1.15

Asked by admin @ 11/08/2021 in Chemistry viewed by 283 persons

A first order reaction has a rate constant 1.15*10^-3.how long will 5g of this reactant take to reduce to 3g ?. PLEASE VERY URGENT

The rate of a first order reaction is 0.04

Asked by admin @ 11/08/2021 in Chemistry viewed by 284 persons

The rate of first order reaction is 0.04 mol per litre sec at 10 min and 0.03 mol per litre sec at 20 min after initiation find half life of …

Decomposition of h2o2 follows a first order reaction

Asked by admin @ 29/08/2021 in Chemistry viewed by 349 persons

Decomposition of h2o2 follows a first order reaction. In fifty minutes the concentration of h2o2 decreases from 0.5 to 0.125 m in one such decomposition. When the concentration of h2o2 …

The reaction a to b follows first order kinetics

Asked by admin @ 17/08/2021 in Chemistry viewed by 296 persons

the reaction A->B follows a first order kinetics. the time taken for 0.8 mole of A to produce 0.6 mole of B is 1 hour . what is the time …

Write a balanced overall reaction from these unbalanced half-reactions.

Asked by maham237 @ 18/12/2020 in Chemistry viewed by 281 persons

Sn->Sn2+ Ag+->Ag Balanced overall equation I got Sn+2Ag+->Sn+2Ag, but its wrong.

The first stage in the life cycle of a star

Asked by admin @ 22/11/2021 in Biology viewed by 355 persons

Place the stages of a high-mass star's life cycle in the correct order, from a star's birth to its death. supernova protostar nebula neutron star Supergiant

How did the creature feel when he first felt life

Asked by admin @ 05/11/2021 in English viewed by 277 persons

Why does Frankenstein’s creature feel lonely? How has mankind contributed to the creature’s feelings of loneliness? Have you ever felt lonely like the creature? Cite examples from the text, your …

How do you find the half life of carbon 14

Asked by admin @ 05/11/2021 in Mathematics viewed by 388 persons

The half-life of carbon-14 is 5730 years. How long will it take for 7/8 of a sample of carbon-14 to decay? 11,460 years 17,190 years 22,920 years 28,650 years

What is the life cycle of a star in order

Asked by admin @ 29/10/2021 in Biology viewed by 286 persons

Place the stages of a high-mass star's life cycle in the correct order, from a star's birth to its death. supernova protostar nebula neutron star Supergiant