Archeologists can determine the age of artifacts made of wood or bone by measuring the amount of the radioactive isotope 14C present in the object. The amount of isotope decreases in a first-order process. If 15.5% of the original amount of 14C is present in a wooden tool at the time of analysis, what is the age of the tool? The half-life of 14C is 5730 yr.

Answers

Answer 1

Answer: The age of the tool is 15539 years

Explanation:

Expression for rate law for first order kinetics is given by:

[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]

where,

k = rate constant  

t = age of sample

a = let initial amount of the reactant = 100

a - x = amount left after decay process = [tex]\frac{15.5}{100}\times 100=15.5[/tex]  

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.  

[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]

[tex]k=\frac{0.693}{5730yr}=0.00012yr^{-1}[/tex]

b) for 15.5 % of original amount

[tex]t=\frac{2.303}{0.00012}\log\frac{100}{15.5}[/tex]

[tex]t=15539years[/tex]

Thus age of the tool is 15539 years


Related Questions

In this reaction diagram, which part represents the difference in energy
between the reactants and the products?
Potential energy
HA
Reaction progress

Answers

Answer:

Option D. G

Explanation:

In the energy profile diagram, the difference in the energy between reactant and product is called enthalphy Change (ΔH).

Mathematically, the enthalpy change (ΔH) is represented as:

Enthalpy change (ΔH) = Heat of product (Hₚ) – Heat of reactant (Hᵣ)

ΔH = Hₚ – Hᵣ

Considering the diagram given in question above, the difference in the energy of product and reactant is indicated by the letter G

Thus, option D gives the correct answer to the question.

What is the meaning of a null hypothesis being rejected?
The hypothesis is definitely correct.
The hypothesis might be correct.
The hypothesis is false.
The null hypothesis is correct.

Answers

Answer:

the hypothesis is false

Explanation:

it I rejected because the hypothesis has been tested severally and the answer still proves to be wrong

Answer:

probably the third option: The hypothesis is false

Explanation:

help help help help

Answers

Answer:

2,4,6–trimethylheptanal

Explanation:

To name the compound given, we must first obtain the following:

1. Determine the functional group of the compound.

2. Determine the longest continuous carbon chain. This gives the parent name of the compound.

3. Identify the substituent group attached to the compound.

4. Locate the position of the substituent group.

5. Combine the above to obtain the name of the compound.

Now, we shall name the compound as follow:

1. The functional group of the compound is –CHO. Thus, the compound is an alkanal.

2. The longest continuous carbon chain is 7. Thus, the parent of the compound is heptanal.

3. The substituent group attached to the compound is methyl (–CH₃).

NOTE: There are 3 methyl groups attached to the compound.

4. The methyl groups attached to compound are located at carbon 2, 4 and 6.

5. Therefore, the name of the compound is:

2,4,6–trimethylheptanal

calculate the molar mass of sodium carbonate

Answers

Answer:

Explanation:

105.9888 g/mol

Answer:

105.9888 g/mol

Explanation:

You will add both the molar mass of each element multiply by the number of atoms present.

Someone please help !!!!!

Sodium chromate can be prepared by oxidizing a chromium(III) salt with sodium peroxide in alkaline
solution. The chromium(III) ions are oxidized to chromate ions. The peroxide ions are reduced to hydroxide
ions. Write down unbalanced half reaction equations and a balanced overall equation for the reaction.
The physical states of all the reagents and products must be shown throughout.

Answers

H⁣⁣⁣⁣⁣ere's l⁣⁣⁣⁣ink t⁣⁣⁣⁣o t⁣⁣⁣⁣he a⁣⁣⁣⁣nswer:

bit.[tex]^{}[/tex]ly/3a8Nt8n

Please help with completing number 5

Answers

Answer:

D.

Explanation:

NH3 (Ammonia) is a water soluble gas, and is polar. While C6H14 is non-polar and does not mix with water soluble.

When 565g of a metal with temperature of 90.00 C added to 200.0 g of water at 25.00 degrees. Assuming all the heat lost by the iron is transferred to the water ( specific heat capacity of water = 4/18 J/(g-C)), and the final temperature of the mixture is 34.40 degree Celsius what is the heat capacity of the metal?

Answers

Answer:

The specific heat is 0.25J/g°C

Explanation:

To solve this question we must know that the heat released for the metal is equal to the heat absorbed for the water. The equation is:

S(Metal)*m(Metal)*ΔT(metal) = S(water)*m(water)*ΔT(water)

Where S of metal is our incognite (Specific heat of metal)

m is the mass of the metal = 565g

ΔT is change in heat of the metal = 90.00°C - 34.40°C = 55.60°C

Specific heat of water = 4.18J/g°C

The mass of water = 200.0g

ΔT of water is 34.40°C - 25.00°C = 9.40°C

Replacing:

S(Metal)*565g*55.60°C = 4.18J/g°C*200.0g*9.40°C

S(metal) = 0.25J/g°C

The specific heat is 0.25J/g°C

1 point C3Hg(g) + 5 O2(g) → 3 CO2(g) + 4H2O(g)

If 0.678 g of propane (C3Hg) are used in the reaction, how many liters of oxygen gas are required to react completely at STP?
Molar mass of C3Hg = 44.11 g/mol
0.077 L
1.72 L
75.9L
0.015L​

Answers

Answer: 1.72

Explanation:

Calculate mass in grams in 2.28 mol of h2so4

Answers

223.44 grams is the answer. Multiply 2.28 times the gram formula mass of h2so4

Answer:

224g

Explanation:

Molar mass of h2so4:

1.008x2+32.06+16.00x4=98.08g/mol

2.28 x 98.08=224g

HELP PLEASE
The blank
and the blank
of atoms are the same on both sides of a chemical equation.

Answers

Answer:

which states that matter cannot be created or destroyed. Therefore, there must be the same number of atoms of each element on each side of a chemical equation.

Explanation:

PLZ HELP I WILL GIVE BRAINLIEST!!!
The light is most intense where it strikes Earth ___________ to its surface.

Answers

Answer:

the sun's Rays strike Earth surface most directly at the Equator this focuses the race on a small area because be raised hit more directly the area is heated more

Explanation:

yw

1.35 m solution NaOCl in water is prepared. What is the mole fraction of the NaOCl?

Answers

Answer:

NaOCl + H2O → HOCl + NaOH

so the mole fraction is = moles of NaOCl/(moles of NaOCl+moles of H2O)

so for 1.35 NaOCl it will require 1.35 moleof H2O

mole fraction = 1.35/(1.35+1.35)

mole fraction = 1/2 =0.5

is it correct i d ek but i tried :)

The mole fraction of the NaOCl is 0.0237

We'll begin by calculating the mole of solute (NaOCl) in the solution.

Molality = 1.35 mMass of water = 1 KgMole of NaOCl =?

Mole = Molality x mass (Kg) of water

Mole of NaOCl = 1.35 × 1

Mole of NaOCl = 1.35 mole

Next, we shall determine the mole of water.

Mass of water = 1 Kg = 1000 gMolar mass of water = 18.01 g/mol Mole of water =?

Mole = mass / molar mass

Mole of water = 1000 / 18.01

Mole of water = 55.52 moles

Finally, we shall determine the mole fraction of NaOCl.

Mole of NaOCl = 1.35 moleMole of water = 55.52 moles Total mole = 1.35 + 55.52 = 56.87 moles Mole fraction of NaOCl =?

Mole fraction = mole / total mole

Mole fraction of NaOCl = 1.35 / 56.87

Mole fraction of NaOCl = 0.0237

Learn more about mole fraction:

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2NH3(g)+3CuO(s)= + 3H2O(I)+N2(g)
If a sample of 51.0g of ammonia's reacted with excess copper oxide, how many moles of nitrogen would be produced?

Answers

Answer:

1.50 mol N₂

Explanation:

Step 1: Write the balanced equation

2 NH₃(g) + 3 CuO(s) ⇒ 3 Cu + 3 H₂O(I) + N₂(g)

Step 2: Calculate the moles corresponding to 51.0 g of NH₃

The molar mass of NH₃ is 17.03 g/mol.

51.0 g × 1 mol/17.03 g = 2.99 mol

Step 3: Calculate the moles of N₂ produced from 2.99 moles of NH₃

The molar ratio of  NH₃ to N₂is 2:1. The moles of N₂ produced are:

2.99 mol NH₃ × 1 mol N₂/2 mol NH₃ = 1.50 mol N₂

what is the acceleration of a 100kg object being pushed with a force of 1000 newton's

Answers

Answer:

the person that answered it with the link, dont click it's a virus

Explanation:

Whose ideas were based on scientifically gathered evidence?
A. Aristotle and alchemists
B. Aristotle and John Dalton
C. John Dalton and Marie Curie
D. Marie Curie and alchemists

Answers

Answer:

Maybe c?

Explanation:

John Dalton was an English chemist, and Marie Curie was a physicist and chemist. The ideas of John Dalton and Marie Curie were based on scientifically gathered evidence. Thus, option C is correct.

Who are John Dalton and Marie Curie?

John Dalton and Marie Curie are famous physicists and chemists. John Dalton is most known for introducing the theory of the atom and color blindness. He gave the theory of atomism based on the experimental setup.

Marie curie hugely contributed to the discovery of radioactivity and cancer research. She and her husband experimented and searched for the radioactive material.

Aristotle was a philosopher and established the relation between the various fields of sciences. He originated the idea of Alchemy by combining the four elements.

Therefore, John Dalton and Marie Curie proposed ideas based on research.

Learn more about Marie Curie here:

https://brainly.com/question/23920465

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What combinations of up and down did quarks combine to make the proton?

A. Down + down + down
B. Up+Up+ down
C. Up+Up+Up
D. Up+down+down
E. Up+down

Answers

Answer:

it is b

Explanation:

b is the quarks for a proton

Answer:

B

Explanation:

HELP HELP HELP HELP!!!!!!!

Answers

Answer:

About 200 moles water

Explanation:

O2 is the limiting reactant, and it allows for 193.75 moles of water to be produced. Good luck on your assignment!

PLEASE HELP !! ILL GIVE BRAINLIEST !! 100 POINTS
IF YOU KNOW CHEMISTRY OR BIOLOGY

Answers

I am 100% positive it is C. Have a ice day ( ^ω^ )

What is the pH of a solution with [OH-]=0.0004? (Show your work)

NO LINKS
Please help

Answers

Answer:

10.6

Explanation:

We'll begin by calculating the pOH of the solution. This can be obtained as follow:

Concentration of Hydroxide ion [OH¯] = 0.0004 M

pOH =?

pOH = –Log [OH¯]

pOH = –Log 0.0004

pOH = 3.4

Finally, we shall determine the pH of the solution. This can be obtained as follow:

pOH = 3.4

pH =?

pH + pOH = 14

pH + 3.4 = 14

Collect like terms

pH = 14 – 3.4

pH = 10.6

Thus, the pH of the solution is 10.6

Consider an atom that has an electron in an excited state. The electron falls to a lower energy level. What effect does that have on the electron?

Answers

Answer:

On returning to lowest energy state which is stable, it releases energy in the form of light. Hence, option A that is the electron releases energy in the form of light on falling to lower energy state from excite state.

what blood vessels and chambers of the heart does a red blood cell pass as it delivers oxygen from the lungs to the brain and return to be oxygenated again.

Answers

Answer:

capillaries

Explanation:

hope it helps if I'm not tell me right away.

Answer:

Carotid artery, Jugular veins

The chambers are explained below.

Explanation:

THE BLOOD VESSELS

The carotid artery carries red blood (oxygenated) to the head and the neck region and that obviously include the brain via the aorta. To be precise the internal carotid artery supplies oxygenated red blood cells to brain. The jugular veins carry deoxygenated red blood cells from the head back to the heart via the superior vena cava. The most important function of the jugular vein is to drain deoxygenated blood from brain.

THE CHAMBERS

The left atrium receives oxygenated blood from the lungs and pumps it to the left ventricle which also pumps the same oxygenated blood to the rest of the body through the aortic valve (aorta).

The right atrium receives deoxygenated blood from the body via the vena cava  and pumps the deoxygenated blood to the right ventricle which pumps the deoxygenated blood to be oxygenated by the lungs via the pulmonary valve (pulmonary artery).

CONCLUSION

The oxygenated red blood cells from the lung pass through the pulmonary vein through the left atrium to the left ventricle through the carotid artery (internal carotid artery) via the aorta to the brain and

The deoxygenated red blood cells in the brain are drained through the jugular vein via the superior vena cava to the right atrium, which pumps the deoxygenated blood to the right ventricle. From here the deoxygenated blood is pumped to the lungs via the pulmonary artery for oxygenation.

This is my answer, thus if I got your question right.

For lunch today, I ate an apple. What type of carbohydrate did I ingest?

Answers

Answer:

Monosaccharide

Explanation:

Apples contain high levels of fructose, which is a monosaccharide.

how is the air in tube 4 kept out of contact with the nail​

Answers

Answer:

If you ever wonder why nails rust, it's because rusting happens when a metal is exposed to oxygen. The molecules of iron on the surface of the nail exchange atoms with the oxygen in the air and produce a new substance, the reddish-brown ferrous oxide, a.k.a. rust.

Explanation:

please mark this answer as brainliest

1)
Steel Wool Experiment
Before
Observations
After
Observations
Appearance
Steel wool dark gray,
Balloon deflated
Appearance
Steel wool dark
brown; Balloon
inflated
Mass (9)
485.68
Mass (9)
The students data can be seen here. A chemical reaction clearly took
place in the flask. One entry is missing: the mass of the system at the
end of the experiment. What amount should be added to the data
table?

Answers

Answer:

Chemical reactions, chemistry, science as inquiry and data analysis. ... Students burn steel wool in both an open and closed environment to understand ... The difference in mass for this small sample of steel wool will be very small. ... careful attention to the balloon! 9. When rusting occurs the properties of the metal changes.

Explanation:

Consider these two entries from a fictional table of standard reduction potentials.

X3++3e−⟶X(s)o=−2.11 V

Y3++3e−⟶Y(s)o=−0.22 V

What is the standard potential of a galvanic (voltaic) cell where X is the anode and Y is the cathode?

ocell=
V

Answers

Answer:

1.89 V

Explanation:

To calculate the standard cell potential, subtract the reduction potential of the anode from the reduction potential of the cathode.

So for your calculation,

-0.22 V - (-2.11 V)= 1.89 V

In the voltaic cell, current is produced by a  sponteanous chemical reaction. The standard cell potential here is 1.89 V.

What is a voltaic cell?

A voltaic cell is a cell that produces current by a sponteanous chemical reaction. We are told here that X is the anode and Y is the cathode.

Now;

E°cell = E°cathode - E°anode

E°cell = (−0.22 V) - (−2.11 V) = 1.89 V

Learn more about voltaic cell:https://brainly.com/question/9904853

Which best explains why ionization energy tends to decrease from the top to the bottom of a group? The number of orbitals decreases. The number of neutrons decreases. Electrons get closer to the nucleus. Electrons get farther from the nucleus.

Answers

Answer:

Electrons get farther from the nucleus.

Explanation:

By going from the top to the bottom of a group, the atomic number increases. That would mean that:

The number of orbitals increases, as there are more electrons.A higher atomic number implies an increasing number of neutrons.As there are more electrons, they get farther from the nucleus. The farther an electron is from the nucleus, the easier it is for the electron to be removed from the atom.

Ionization energy decreases down the group because electrons get farther from the nucleus hence they are easier to remove.

Ionization energy refers to the energy required to remove an electron from  an atom. The ionization energy is a periodic trend that decreases down the group but increases across the period.

The ionization energy decreases down the group because electrons get farther from the nucleus hence they are easier to remove.

Learn more: https://brainly.com/question/16243729

what is ionisation energy​

Answers

Answer:

minimum energy required to to remove the most loosely bound election of an isolated gaseous atom.

Explanation:

20 POINTS PLEASE ANSWER
In the following reaction, if you wanted to produce more hydrochloric acid (HCl), what should you do? (2 points)
4HCl + O2 ⇄ 2H2O + Cl2

Select one:
a. Add more H2O
b. Add more O2
c. Remove H2O
d. Remove Cl2

Answers

Answer:

Add more H2O

Explanation:

Consider the following reaction
X + Al(NO3)3 (aq) → X(NO3)y (aq) + Al(s)
Using the provided Activity Series of Elements, determine which of the following elements could be X.

a. Copper b. Lead c. Iron d. Calcium

Answers

Answer: Calcium

Explanation: an element need to reduce Iron in reaction.

Calcium is only metal in list which can reduce Iron

The fluorine-17 nuclide radioactively decays by electron capture.

Answers

Answer: daughter nucleus is Oxygen-17

Explanation: electron and proton form a neutron in nucleus.

Mass number remains same and number of proton decreases.

Fluorine -17 isotope undergoes nuclear decay by electron capture results in the formation of the oxygen-17 nuclei and one neutron as written below:

[tex]\rm _{9}^{17}F + _{-1}^{0}e \rightarrow _{9}^{1 7}O + _{0}^{1}n[/tex]

What is nuclear decay?

Unstable radioactive isotopes of some elements undergoes breaking their nuclei by emitting or absorbing some charged particles such as alpha or beta.

Alpha decay result in the emission of one helium  nuclei where, the mass number reduces by 4 units and atomic number by 2. In beta decay mass umber does not change but atomic number increases by one.

The process of electron capture, is the bombardment of an electron into the unstable nucelli result where the atomic number reduces by one. Therefore, fluorine converts to oxygen -17 by electron capture where the latter isotope is stable one.

To find more on nuclear decay, refer here:

https://brainly.com/question/12224278

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Your question is incomplete. But your complete question probably was:

Fluorine-17 nuclide radioactively decays by electron capture. Write a balanced nuclear chemical equation that describes this process.

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