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makvit [3.9K]
3 years ago
12

Scientists found a fern fossil in some rock layers of the Grand Canyon. They estimated that a sample of one of the fossils origi

nally contained 1000 carbon-14 atoms when it became 'fossilized', and at the time it was tested, it only contained 250 carbon-14 atoms. Look at the chart below. How old is the fossil?
Chemistry
1 answer:
icang [17]3 years ago
3 0
This question is dealing with the half-life of carbon-14 which can be used to determine the age of a substance according to the following equation:

t = [ln(N/No)/(-ln2)] · t1/2

N = # of carbon-14 atoms presently = 250 atoms
No = # of carbon-14 atoms initially = 1000 atoms
t1/2 = half-life = 5730 years for carbon-14

We can now input all of the information into the formula to find the age of the fossil:

t = [ln (250/1000)/-ln2] x 5730 years

t = 11460 years

The fossil should be found to be roughly 11,460 years old.
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The lightest particle among the following is :
Triss [41]

The question is incomplete, the complete question is;

The lightest particle among the following is:

• Electron •Proton • Neutron • Alpha​

Answer:

Electron

Explanation:

There three basic subatomic particles are electrons, protons and neutrons. Both protons and neutrons are found in the nuclear and both contribute towards the mass of the atom. The alpha particle has the same mass as the helium nucleus.

However, the electrons are found in orbiit and have a negligible mass compared to the mass of the protons and neutrons. The mass of the electron is about 9.11 × 10^-31 Kg. This makes it the lightest of all the particles listed among the options.

3 0
3 years ago
Which isotope will spontaneously decay and emit particles with a charge of +2?
VikaD [51]

Answer: The correct option is 4.

Explanation: All the options will undergo some type of radioactive decay processes. There are 3 decay processes:

1) Alpha decay: It is a decay process in which alpha particle is released which has has a mass number of 4 and a charge of +2.

_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha

2) Beta-minus decay: It is a decay in which a beta particle is released. The  beta particle released has a mass number of 0 and a charge of (-1).

_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta

3) Beta-plus decay: It is a decay process in which a positron is released. The positron released has a mass number of 0 and has a charge of +1.

_Z^A\textrm{X}\rightarrow _{Z-1}^A\textrm{Y}+_{+1}^0\beta

For the given options:

Option 1: This nuclei will undergo beta-plus decay process to form _{25}^{53}\textrm{Mn}

_{26}^{53}\textrm{Fe}\rightarrow _{25}^{53}\textrm{Mn}+_{+1}^0\beta

Option 2: This nuclei will undergo beta-minus decay process to form _{80}^{198}\textrm{Hg}

_{79}^{198}\textrm{Au}\rightarrow _{80}^{198}\textrm{Hg}+_{-1}^0\beta

Option 3: This nuclei will undergo a beta minus decay process to form _{56}^{137}\textrm{Ba}

_{55}^{137}\textrm{Cs}\rightarrow _{56}^{137}\textrm{Ba}+_{-1}^0\beta

Option 4: This nuclei will undergo an alpha decay process to form _{85}^{216}\textrm{At}

_{87}^{220}\textrm{Fr}\rightarrow _{85}^{216}\textrm{At}+_2^4\alpha

Hence, the correct option is 4.

7 0
4 years ago
Read 2 more answers
Why does photosynthesis require 6 molecules of carbon dioxide and 6 molecules of water to make 1 molecule of glucose
Scilla [17]

For each molecule of glucose produced: 6 water water molecules are oxidized, and come to be the supply of electrons for carbon dioxide reduction. 6 molecules of carbon dioxide are required, one for every carbon atom in glucose. 6 molecules of oxygen are produced as a with the aid of made from water oxidation.

6 0
3 years ago
during which of the following processes does the entropy of the system decrease? salt crystals dissolve in water air escapes fro
Nat2105 [25]
<h2>Entropy of the system decreases when methane gas and oxygen gas  combust to form carbon dioxide and water.</h2>

Explanation:

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Hence, the option (a), (b), (c), and (d) are not suitable to the statement                       that  "the entropy of the system decreases".

  • During combustion of methane gas there is release of carbon dioxide gas and water .Here, entropy decreases due to the formation of water which is due to overall decrease in the  kinetic energy of the system.
4 0
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When you open a bottle of soda,bubbles of carbon dioxide start appearing. Is this a chemical or physical change and why?
miss Akunina [59]
If bubbles aren't a for sure way of knowing a chemical reaction I don't know what is. But being for real, it is a chemical change because the bubbles are releasing carbon dioxide meaning it turned into a product from a reaction with outside forces.
6 0
3 years ago
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