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deff fn [24]
3 years ago
7

The carbon-14 content of a wooden harpoon handle found in an Inuit archaeological site was found to be 61.9% of the carbon-14 co

ntent in a normal living piece of wood. If the half-life of carbon-14 is 5,730 years, how old is the harpoon handle?
Chemistry
1 answer:
astraxan [27]3 years ago
7 0

Answer:

3,964 years.

Explanation:

  • It is known that the decay of a radioactive isotope isotope obeys first order kinetics.
  • Half-life time is the time needed for the reactants to be in its half concentration.
  • If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).
  • Also, it is clear that in first order decay the half-life time is independent of the initial concentration.

  • The half-life of the element is 5,730 years.

  • For, first order reactions:

<em>k = ln(2)/(t1/2) = 0.693/(t1/2).</em>

Where, k is the rate constant of the reaction.

t1/2 is the half-life of the reaction.

∴ k =0.693/(t1/2) = 0.693/(5,730 years) = 1.21 x 10⁻⁴ year⁻¹.

  • Also, we have the integral law of first order reaction:

<em>kt = ln([A₀]/[A]),</em>

where, k is the rate constant of the reaction (k = 1.21 x 10⁻⁴ year⁻¹).

t is the time of the reaction (t = ??? year).

[A₀] is the initial concentration of the sample ([A₀] = 100%).

[A] is the remaining concentration of the sample ([A] = 61.9%).

∴ t = (1/k) ln([A₀]/[A]) = (1/1.21 x 10⁻⁴ year⁻¹) ln(100%/61.9%) = 3,964 years.

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valentina_108 [34]

Answer:

The molarity of the solution is 0,31 M

Explanation:

We calculate the weight of 1 mol of NaCl from the atomic weights of each element of the periodic table. Then, we calculate the molarity, which is a concentration measure that indicates the moles of solute (in this case NaCl) in 1000ml of solution (1 liter)

Weight 1 mol NaCl= Weight Na + Weight Cl= 23 g + 35, 5 g= 58, 5 g

58, 5 g-----1 mol NaCl

13,1 g ---------x= (13,1 g x 1 mol NaCl)/58, 5 g= 0, 224 mol NaCl

727 ml solution------ 0, 224 mol NaCl

1000ml solution------x= (1000ml solutionx0, 224 mol NaCl)/727 ml solution

x=0,308 mol NaCl---> <em>The solution is 0,31 molar (0,31 M)</em>

5 0
3 years ago
Hello there
Mumz [18]
The answer is the third one because density is mass divided by volume so 80 divided by 10 is 8
6 0
2 years ago
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10 points. Please help.
ratelena [41]

Answer:

-191.7°C

Explanation:

P . V = n . R . T

That's the Ideal Gases Law. It can be useful to solve the question.

We replace data:

2.5 atm . 8 L = 3 mol . 0.082 L.atm/mol.K . T°

(2.5 atm . 8 L) / (3 mol . 0.082 L.atm/mol.K) = T°

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We convert T° from K to C°

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Romashka-Z-Leto [24]

Answer:

Nucleotides

Explanation:

Nucleotides are the organic molecules which serve as monomer units for the formation of nucleic acid polymers which are the deoxyribonucleic acid and the ribonucleic acid (RNA) and both are the essential biomolecules within the life on the Earth.

Nucleotides are building blocks of the nucleic acids. They are the molecules which are composed of three sub units which are:  

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Which chemical formula corresponds to this structural formula? h6c6h6h2 c14h6 c6h6 c2h6o
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C₂H₆O is referred to the chemical formula corresponds to this structural formula and is denoted as option D.

<h3>What is Chemical formula?</h3>

This contains information about the chemical proportion of atoms present in a molecule.

In this scenario, there are two carbon atoms, six hydrogen atoms and one oxygen atom which can be written as C₂H₆O. This is therefore the most appropriate choice in this scenario.

Read more about Chemical formula here brainly.com/question/26388921

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