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March 5, 2021

Why does crystal violet lose its color upon exposure to base?

Why does crystal violet lose its color upon exposure to base?

The color is due to continuous movement of electrons between single and double bonds. When crystal violet reacts with a base (OH), the conjugation is disrupted and the color is lost.

What is the rate law for crystal violet and NaOH?

Introduction. The rate law for this reaction is in the form: rate = k[CV+]m[OH]n, where k is the rate constant for the reaction, m is the order with respect to crystal violet (CV+), and n is the order with respect to the hydroxide ion.

Does the rate of fading depend on the concentration of the dye?

The rate of fading is dependent on ionic strength or ion concentration of the reaction solutions. Since the reaction requires that two negatively charged ions approach each other, their repulsion is decreased if the overall ionic strength of the reaction solutions remains constant.

What is the order with respect to CV+?

Upon reaction with NaOH the conjugation gets disrupted and the color is lost. The rate law for reaction (1) is of the form: rate = k [CV+]m[OH]n, where k is the rate constant for the reaction m is the order with respect to crystal violet (CV+) n is the order with respect to the hydroxide ion.

What is the order of reaction with respect to crystal violet?

Thus, the order of reaction (m) with respect to crystal violet is first.

Is Crystal Violet a first order reaction?

Discoloration ofcrystal violet is first order with respect to the concentration of crystal violet and hydroxyl ion concentration.

Is Crystal Violet toxic?

It acts as a mitotic poison, potent carcinogen and a potent clastogene promoting tumor growth in some species of fish. Thus, CV is regarded as a biohazard substance.

How do you determine the order of a reaction?

The overall order of the reaction is found by adding up the individual orders. For example, if the reaction is first order with respect to both A and B (a = 1 and b = 1), the overall order is 2. We call this an overall second order reaction.

What is half life of first order reaction?

The half-life of a chemical reaction, regardless of its order, is simply the time needed for half of an initial concentration of a reactant to be consumed by the reaction. Now, a first-order reaction is characterized by the fact that the rate of the reaction depends linearly on the concentration of one reactant.

What is 2nd order reaction?

Definition of second-order reaction : a chemical reaction in which the rate of reaction is proportional to the concentration of each of two reacting molecules — compare order of a reaction.

Is half life dependent on concentration?

Since the half-life equation of a first-order reaction does not include a reactant concentration term, it does not rely on the concentration of reactant present. In other words, a half-life is independent of concentration and remains constant throughout the duration of the reaction.

How do you calculate half life?

18:02Suggested clip 113 secondsHalf Life Chemistry Problems – Nuclear Radioactive Decay …YouTubeStart of suggested clipEnd of suggested clip

What is the formula for radioactive half life?

However, the half-life can be calculated from the decay constant as follows: half-life = ln (2) / (decay constant). To measure the decay constant, we take a sample of known mass and measure the number of radioactive decays per second as a function of time.

What is the symbol of Half Life?

Half-life (symbol t1⁄2) is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo, or how long stable atoms survive, radioactive decay.

How do you calculate age from half lives?

3:30Suggested clip 115 secondsFind Age of Substance From Given Half Life Exponential Decay …YouTubeStart of suggested clipEnd of suggested clip

How can you tell how old a radioactive sample is?

Radiometric dating, often called radioactive dating, is a technique used to determine the age of materials such as rocks. It is based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.

What is the half life of a radioactive isotope?

The rate at which a radioactive isotope decays is measured in half-life. The term half-life is defined as the time it takes for one-half of the atoms of a radioactive material to disintegrate. Half-lives for various radioisotopes can range from a few microseconds to billions of years.

What is K in Half Life?

Now that we know our half-life, we can plug that in and get K, so it’s 0.693 divided by 2.16 times ten to the four seconds. If we plug this into our calculator, we get that K is equal to 3.21 times ten to the minus five, and our units are one over seconds.

What is K in radioactive decay?

Since the rate of radioactive decay is first order we can say: r = k[N]1, where r is a measurement of the rate of decay, k is the first order rate constant for the isotope, and N is the amount of radioisotope at the moment when the rate is measured.

Is Half Life negative?

It has a negative sign because the number of nuclei of the isotope will decrease over time. The rate of decay is equal to the number of the nuclei multiplied by a proportionality constant that depends on the exact isotope. Bauer shows the decay of radioactive nuclei as a function of the half-life.