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3 years ago

What is a stable and radioactive isotopes

1 answer:

4 0

All elements with atomic numbers greater than 83 areradioisotopes meaning that these elements haveunstable nuclei and are radioactive. Elements with atomic numbers of 83 and less, have isotopes (stablenucleus) and most have at least one radioisotope (unstable nucleus).

A Radioisotope is also an isotope by nature. The difference is that radioisotopes are very unstable and contain high levels of nuclear energy and emit this energy in the form of nuclear radiation. Main difference: Isotopes can be stable or unstable, but Radioisotopes are always unstable.

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Uranium, an important component of both nuclear weapons and nuclearreactors, has two major isotopes, U-238, which has a half-lif

elixir [45]

Answer:

Hello your question is poorly written below is the well written question

Uranium, an important component of both nuclear weapons and nuclear reactors, has two major isotopes, U-238, which has a half-life of approximately 4.5 billion years, and U-235, which has a half-life of approximately 700 million years. Both were present in equal amounts at the time of the creation of the Earth, 4.5 billion years ago. How many years after the creation of the Earth had the amount of radiation from uranium decayed to half the amount present at the time of the creation of the Earth

Answer : 140 billion years

Explanation:

Given that :

U-238 h1/2 = 4.5 billion years

U-235 h1/2 = 700 million years

At the beginning both Isotopes where present in equal amount

Determine the T years before the amount of Uranium decays to Half

T = ? N'2 = N1 / 2

we know that N = No ( 1/2 )^h where h = time / half-life time

attached below is the detailed solution of the given problem

6 0

2 years ago

An electrochemical cell at 25°C is composed of pure copper and pure lead solutions immersed in their respective ionis. For a 0.6

ExtremeBDS [4]

Answer :

(a) The concentration of $Pb^{2+}$ is, 0.0337 M

(b) The concentration of $Pb^{2+}$ is, $6.093\times 10^{32}M$

Solution :

(a) As per question, lead is oxidized and copper is reduced.

The oxidation-reduction half cell reaction will be,

Oxidation half reaction: $Pb\rightarrow Pb^{2+}+2e^-$

Reduction half reaction: $Cu^{2+}+2e^-\rightarrow Cu$

The balanced cell reaction will be,

$Pb(s)+Cu^{2+}(aq)\rightarrow Pb^{2+}(aq)+Cu(s)$

Here lead (Pb) undergoes oxidation by loss of electrons, thus act as anode. Copper (Cu) undergoes reduction by gain of electrons and thus act as cathode.

First we have to calculate the standard electrode potential of the cell.

$E^o_{[Pb^{2+}/Pb]}=-0.13V$

$E^o_{[Cu^{2+}/Cu]}=+0.34V$

$E^o=E^o_{[Cu^{2+}/Cu]}-E^o_{[Pb^{2+}/Pb]}$

$E^o=0.34V-(-0.13V)=0.47V$

Now we have to calculate the concentration of $Pb^{2+}$ .

Using Nernest equation :

$E_{cell}=E^o_{cell}-\frac{0.0592}{n}\log \frac{[Pb^{2+}]}{[Cu^{2+}]}$

where,

n = number of electrons in oxidation-reduction reaction = 2

$E_{cell}$ = 0.507 V

Now put all the given values in the above equation, we get:

$0.507=0.47-\frac{0.0592}{2}\log \frac{[Pb^{2+}]}{(0.6)}$

$[Pb^{2+}]=0.0337M$

Therefore, the concentration of $Pb^{2+}$ is, 0.0337 M

(b) As per question, lead is reduced and copper is oxidized.

The oxidation-reduction half cell reaction will be,

Oxidation half reaction: $Cu\rightarrow Cu^{2+}+2e^-$

Reduction half reaction: $Pb^{2+}+2e^-\rightarrow Pb$

The balanced cell reaction will be,

$Cu(s)+Pb^{2+}(aq)\rightarrow Cu^{2+}(aq)+Pb(s)$

Here Copper (Cu) undergoes oxidation by loss of electrons, thus act as anode. Lead (Pb) undergoes reduction by gain of electrons and thus act as cathode.

First we have to calculate the standard electrode potential of the cell.

$E^o_{[Pb^{2+}/Pb]}=-0.13V$

$E^o_{[Cu^{2+}/Cu]}=+0.34V$

$E^o=E^o_{[Pb^{2+}/Pb]}-E^o_{[Cu^{2+}/Cu]}$

$E^o=-0.13V-(0.34V)=-0.47V$

Now we have to calculate the concentration of $Pb^{2+}$ .

Using Nernest equation :

$E_{cell}=E^o_{cell}-\frac{0.0592}{n}\log \frac{[Cu^{2+}]}{[Pb^{2+}]}$

where,

n = number of electrons in oxidation-reduction reaction = 2

$E_{cell}$ = 0.507 V

Now put all the given values in the above equation, we get:

$0.507=-0.47-\frac{0.0592}{2}\log \frac{(0.6)}{[Pb^{2+}]}$

$[Pb^{2+}]=6.093\times 10^{32}M$

Therefore, the concentration of $Pb^{2+}$ is, $6.093\times 10^{32}M$

6 0

3 years ago

What makes slime, slime?

Naya [18.7K]

Slime flows like a liquid, but unlike familiar liquids (e.g., oil, water), its ability to flow, or viscosity, is not constant. So it's a fluid, but not a regular liquid. Scientists call a material that changes viscosity a non-Newtonian fluid. The technical explanation is that slime is a fluid that changes its ability to resist deformation according to shear or tensile stress.

What this means is, when you pour slime or let it ooze through your fingers, it has a low viscosity and flows like a thick liquid. When you squeeze a non-Newtonian slime, like oobleck, or pound it with your fist, it feels hard, like a wet solid. This is because applying stress squeezes the particles in the slime together, making it hard for them to slide against each other.

Most types of slime are also examples of polymers. Polymers are molecules made by linking together chains of subunits.

The specifics of how a type of slime works depends on its chemical composition, but the basic explanation is that chemicals are mixed to form polymers. The polymers act as a net, with molecules sliding against each other.

Two solutions are combined to make classic slime. One is diluted school glue, or polyvinyl alcohol in water. The other solution is borax (Na2B4O7.10H2O) in water.
Borax dissolves in water into sodium ions, Na+, and tetraborate ions.
The tetraborate ions react with water to produce the OH- ion and boric acid:
B4O72-(aq) + 7 H2O <—> 4 H3BO3(aq) + 2 OH-(aq)
Boric acid reacts with water to form borate ions:
H3BO3(aq) + 2 H2O <— > B(OH)4-(aq) + H3O+(aq)
Hydrogen bonds form between the borate ion and the OH groups of the polyvinyl alcohol molecules from the glue, linking them together to form a new polymer: slime.

6 0

3 years ago

Read 2 more answers

A glass blower can bend and shape a piece of glass that has been heated. Is glass a crystalline or an amorphous solid?

zavuch27 [327]

it would be a crystalline solid, because it could be extended in multiple directions.

5 0

3 years ago

Compound element ratio of 1:2:6 Ba(NO3)2+Na2SO4

Karo-lina-s [1.5K]

1:2:6? Ba(NO3)2 +Na2SO4 -----> BaSO4 + 2NaNO3

Ba(NO3)2