All categories

3 years ago

The half life of radon-222 is 3.8 days. How much of a 100 gram sample is left after 15.2 days ?

Chemistry

2 answers:

Natali5045456 [20]3 years ago

5 0

Answer:

6.2 g

Explanation:

1. Calculate the number of half-lives.

2. Calculate the final mass of the substance.

nasty-shy [4]3 years ago

4 0

Answer:

6.3g of the 100g sample will be left after 15.2years

Explanation:

Half life is defined as the time taken by a radioactive substance to decay or reduce to half if its original value.

Mathematically, t1/2 = 0.693/¶ where ¶ is the decay constant.

Firstly, we need to get the decay constant using the formula for half life.

Given half life of radon (t1/2) = 3.8days

3.8 = 0.693/¶

¶ = 0.693/3.8

¶ = 0.182

If the initial value (No) if the substance is 100, the final sample (N) after 15.2years of decay can be gotten using the formula

N= Noe^-¶t where

N is the final sample after decay

No is the initial value of the sample

¶ is the decay constant

t is the time taken NY the object to decay

Given No = 100

¶ = 0.182

t = 15.2years

Substituting in the formula to get N we have;

N = 100e^-0.182(15.2)

N = 100e^-2.7664

N = 100×0.063

N = 6.3g

This shows that the initial value of radon would have decay upto 6.3g after 15.3years

You might be interested in

For the reaction: 2 A (g) + B (s)= 2 C(s) + D (g)

jolli1 [7]

Answer:

The value of the equilibrium constant = 5.213

Explanation:

Here $K_p$ (equilibrium constant) is referred to as the partial pressure of product divided by the partial pressure of reactant with each pressure term raised to power that is equal to its stoichiometric coefficient in balanced equation .

As such only gas appear in $K_p$ expression as solids takes a value of 1;

SO ; in the given equation from the question:

2 A (g) + B (s) ----> 2 C(s) + D (g)

$K_p = \dfrac{[D]}{[A]^2}$

$K_p = \dfrac{2.71}{0.721^2}$

$K_p = 5.213$

The value of the equilibrium constant = 5.213

8 0

3 years ago

Which statement best describes a weak acid?

morpeh [17]

C. Weak acids partially ionize

3 0

3 years ago

Which granulated leukocyte is most likely to be active during a bacterial infection?

77julia77 [94]

It seems that you have missed the necessary options for us to answer this question, so I had to look for it. Anyway, here is the answer. The granulated leukocyte that <span> is most likely to be active during a bacterial infection is the NEUTROPHIL. Hope this answers your question.</span>

7 0

3 years ago

Os the following reaction an SN1 or SN2 reaction ?

Keith_Richards [23]

Answer:

it's SN1 reaction,

it's takin double step to complete,first formation of carbocation and then attack of reagents,so it's SN1!

8 0

3 years ago

Assuming an ionization efficiency of 13.0%, how many such photons are needed to ionize 1.00×1016 atoms?

sammy [17]

Answer:

7.69x $10^{16}$

Explanation:

The ionization is the energy necessary to transform an atom in an anion. So, it's the energy it requires to gain an electron.

This ionization occurs for the photoelectric effect - the emission of electrons by metal using photons. So, if the efficiency is 100%, 1 photon can ionize 1 atom, but for an effficiency of 13.0%:

N = $\frac{1.00x10^{16}}{0.13}$

N = 7.69x $10^{16}$

Where N is the number of photons.

6 0

3 years ago