Radioactive isotope X has a half-life of 500,000 years. This isotope may be found in some types of volcanic rocks. A particular sample of volcanic rock taken from a layer that covered up some of the earliest known human-like footprints contains 0.125 mg of isotope X. The volcanic rock sample originally contained 8.00 mg of isotope X. How long ago were these footprints made. I need the equation. Thanks. please I am stuck on this question. PLEASE

Answers

Answer 1

Answer: The footprints were made [tex]2.99\times 10^6years[/tex] years long ago.

Explanation:

Radioactive decay follows first order kinetics.

Half-life of isotope X= 500,000 years

[tex]\lambda =\frac{0.693}{t_{\frac{1}{2}}}=\frac{0.693}{500000}=0.00000139year^{-1}[/tex]

The equation for first order kinetics is :

[tex]N=N_o\times e^{-\lambda t}[/tex]

N = amount left after time t  = 0.125 mg

[tex]N_0[/tex] = initial amount  = 8.00 mg

[tex]\lambda[/tex] = rate constant

t= time  

Putting the values we get:

[tex]0.125=8.00\times e^{- 0.00000139years^{-1}\times t}[/tex]

[tex]0.0156=e^{- 0.00000139years^{-1}\times t}[/tex]

[tex]t=2.99\times 10^6years[/tex]

The footprints were made [tex]2.99\times 10^6years[/tex] years long ago.


Related Questions

Which tools can be used to measure the volume of a substance? Select the two correct answers.
a. tape measure
b. digital balance
c. measuring cup
d. graduated cylinder

Answers

Perhaps the volumetric flask and the graduated cylinder

Answer:

graduated cylinder and a scale can be used to measure the volume of a substance. hope this is helpful

Explanation:

Summary about helium

Answers

Answer: Helium is an type of air that can be used to inflate balloons, balls,  and other things that require air. The carbon dioxide we breath out is similar to this helium.

Hope this helps!

A substance with a pH of 3 has more ____________ions than ____________ions

Answers

Answer:

Hydrogen... Hydroxide

Explanation:

The number in pH is a logarithm, so when something has a higher pH by 1, it is 100 times more powerful.

Besides, the H in pH is Hydrogen.

A cart has a mass of 35kg and a speed of 1.2m/s. What is its kinetic energy

Answers

Answer:

The answer is 25.2 J

Explanation:

The kinetic energy of an object can be found by using the formula

[tex]KE = \frac{1}{2} m {v}^{2} \\ [/tex]

where

m is the mass

v is the velocity

From the question we have

[tex]KE = \frac{1}{2} \times 35 \times {1.2}^{2} \\ = 17.5 \times 1.44 [/tex]

We have the final answer as

25.2 J

Hope this helps you

Answer:

25.2 J

Explanation:

Using the kinetic energy formula:

KE = [tex]\frac{1}{2}[/tex]m v²

Plug in the given values:

KE = [tex]\frac{1}{2}[/tex] (35 kg) · (1.2 m/s)²

KE = [tex]\frac{1}{2}[/tex] (35) · 1.44

KE = 17.5 · 1.44

KE = 25.2 J

There is a kinetic energy of 25.2 Joules.

How many elements are in this chemical formula?

HCl

Group of answer choices

Answers

2 elements!
first element is H and the second element is Cl

What is the underlying, fundamental force for the formation of all chemical bonds?
A detailed explanation would be best, please.

Answers

Answer:

[tex]it \: is : \\nuleic\: force\: of\: ( attraction \: and \: repulsion).[/tex]

Explanation:

[tex]this \: is \: because, \: for \: any \: type \: of \: chemical \\\: combination \: (bonding) \: to \: be \: possible, \\ there \: must \: exist\: an \: equilibrium \: between \: \\ the \: force \: of \: attraction \: and \: repulsion.[/tex]

Answer:

bonds are formed by joining atoms whether same or different elements to form molecules by uses of forces of attractions

Which of the models best represents CaCO3?

Answers

Answer: B

Explanation:

To solve this we must be knowing each and every concept related to CaCO[tex]_3[/tex]. Therefore,  the correct option is option B among all the given options.

What is CaCO[tex]_3[/tex]?

Carbonate of calcium One of the best-known compounds is CaCO[tex]_3[/tex]. Calcium carbonate is indeed a non-toxic, odorless substance. CaCO[tex]_3[/tex] is a white mineral found naturally in chalks, limestones, and marbles. It is a common material found in rocks as calcite and aragonite.

CaCO[tex]_3[/tex] is most commonly found in limestone. It is a sedimentary rock composed primarily of calcite and is the primary component of eggshells, snail shells, seashells, and pearls. Calcium carbonate is also used in medicine as a source of calcium or as an antacid. Although excessive calcium carbonate ingestion is dangerous and causes poor digestion.

Therefore,  the correct option is option B.

To know more about  CaCO[tex]_3[/tex], here:

https://brainly.com/question/28455207

#SPJ2

Where are hormones produced in animals, and how are they transported throughout the body?
A. Animal hormones are produced in endocrine glands and travel through the blood.
B. Animal hormones are produced in lymph nodes and travel through the lymphatic system.
C. Animal hormones are produced inside the bones and travel through the nervous system.
D. Animal hormones are produced in sweat glands and travel through the skin.

Answers

Answer:

Vertebrate Endocrine Glands and Hormones

Unlike plant hormones, animal hormones are often (though not always) produced in specialized hormone-synthesizing glands (shown below). The hormones are then secreted from the glands into the blood stream, where they are transported throughout the body.

which of the following units of measurement would you use to describe the length of your pencil?

Answers

centimeter. cm.
you can also use it for a book

Answer:

cm

Explanation:

cm is the most appropriate unit - metres is too big and mm is too small

Please help I’ll give brainiest!

Answers

Answer:

Im sorry if u get it worng but is it the 3rd one?

Explanation:

How has cooperation played a role in life's major evolutionary transitions?

Answers

Answer:

The cooperation of a species is shown throughout history. Including in our history. Where it be physical evolution or technological. We have helped each other with building, advice, locations, Reproduction, etc.

put 34,100,000 in scientific notation

Answers

Answer:

3.41 x 10^7

Explanation:

It is a mixture that consists of a liquid solvent and dissolved solute.

Answers

Answer:

A solution is a homogeneous mixture consisting of a solute dissolved into a solvent . ... The solute is the substance that is being dissolved, while the solvent is the dissolving medium. Solutions can be formed with many different types and forms of solutes and solvents.

Answer:

A solution is a homogeneous mixture consisting of a solute dissolved into a solvent .

Explanation:

3. magnesium oxide + ?______________________ magnesium nitrate + water
word equation:
________________________________________________________________
full equation:
________________________________________________________________
Ionic equation:
________________________________________________________________

Answers

Answer:MgO reacts with nitric acid

1. In part 1, you collected data about how the amount of sugar affects the amount of gas produced. Analyze those data and draw a conclusion. (16 points) a. What gas inflated the balloons? (2 points)​

Answers

Answer:

carbohydrate is an essential biomolecule so the affect of suger fluctuates when enzyme consumes the substrates of glucose molecules

Who was martin Luther king and how is he celebrite

Answers

Answer: martin luther king jr

Explanation: He led peaceful protests against the discrimination that the people of the United State did against African American men, women, and children. He was a celebrity due to his have "I a dream speech" that he said in front of the lincoln memorial.  Plus he didn't approve of violence when trying to protest African American rights.

Answer:

Who is Martin Luther King and why is he famous?

Exsplanation

A Baptist pastor and civil rights activist, King worked to end legal segregation of blacks in the United States. He gave his famous “I Have a Dream” speech at the August 1963 March on Washington, and won the Nobel Peace Prize in 1964 at age 35 – the youngest man to have received the award.Apr 4, 2018

what is action force?

Answers

Answer:

is force acting in one direction

Answer:

hope this helps!

as described by the third of Newton's law of motion of classical mechanics, offices occurs in pairs such that is one object exerts a force on another object, then the second object exerts an equal and opposite reaction Force on the first.

Johnny wanted to paint the ceiling of his room to show the stars of the Milky Way galaxy. What color(s) should he use?

Answers

Answer:

He should use black a light purple brown, tan, blue, and just a tiny bit of pink!

Hope this helps!!

Explanation:

If Johnny wanted to show the brightness of the stars, he should use blue, light blue, yellow, orange, red, and white.

What is Milky way??

The Milky Way is a huge collection of stars, dust and gas .

The Milky Way is seen as a mostly flat, irregularly-shaped feature that stretches from side to side The Milky way is the mixture of the colors as blue , yellow , orange  and white so that it express the appearance of brightness of stars , dust and gas

Hence , Johnny should use blue, light blue, yellow, orange, red, and white.

Learn more about milky way below

https://brainly.com/question/13956361

#SPJ2

   

which substance is a mixture? A. table salt B. gasoline C. aluminium D. carbon dioxide​

Answers

B.) Gasoline. Gasoline is a complex blend of compounds made from petroleum. There are various grades of gasoline. Thus it is a mixture

[Ne] 3s^ 2 3p^ 4 can someone tell me the element

Answers

Answer:

Sulpher

Explanation:

For this type of questions; calculate the total number of electrons so that you can identify the element from the periodic table.

Neon has 10 electrons. and from 3s^2 and 3p^4 there are 6 electrons.

So the total number of electrons is 16.

The element is Sulpher from group 6 of the periodic table

I WILL GIVE YOU BRAINLIEST HELP ME!!!

Answers

Answer:

It is the first one

Explanation:

Due to the fact that political discretion would be so only a few or a group of indviduals could control or know certain things

Answer: yeah is the first one

Explanation:


Which statement offers an explanation for why some parts of John Dalton's atomic theory were proven to be false?

Scientists today are more diverse and have more educational training

Mistakes were made in key calculations during experimenting

Extensive repeated testing was not completed to verify the results

Technology available at that time was limited.

Answers

Answer:d

Explanation:

Answer:

The answer is D

Explanation:

I took the test!

2. What type of bonding would be expected between the following atoms?
a. Li and F
c. I and Br
b. Cu and S
d. S and O

Answers

a.) covalent
c.) covalent
b.) ionic
d.) covalent

Considering the definition of covalent and ionic bond, the type of bonding that would be expected between the following atoms is:

Li and F: Ionic Bond I and Br: Covalent Bond Cu and S: Ionic Bond S and O: Covalent Bond

The covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas.  

An ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions. Usually, the metal gives up its electrons forming a cation to the nonmetal element, which forms an anion.

Taking into account the previous definitions, it is first necessary to know if the elements are metallic or non-metallic:

Lithium Li: Metallic atoms Flour F: Non-metallic atoms Iodine I: Non-metallic atomsBromine Br: Non-metallic atomsCopper Cu: Metallic atoms Sulfur S: Non-metallic atoms Oxygen O: Non-metallic atoms

Now you can determine the type of bond of the following pairs of elements:

Li and F: Metallic atoms - Non-metallic atoms: Ionic Bond I and Br: Non-metallic atoms - Non-metallic atoms: Covalent Bond Cu and S: Metallic atoms - Non-metallic atoms: Ionic Bond S and O: Non-metallic atoms - Non-metallic atoms: Covalent Bond

Learn more:

https://brainly.com/question/7869439?referrer=searchResultshttps://brainly.com/question/14526070?referrer=searchResultshttps://brainly.com/question/2468807?referrer=searchResultshttps://brainly.com/question/2468807?referrer=searchResults

I WILL GIVE U BRAINLIEST!!!!!!!

Answers

Answer:

I think its b. if not sorry but its the one that makes most sense

Explanation:

Answer:

B

Explanation:

Hope this helps you have a nice day!

What subatomic particle identifies any type of
atom?

Answers

Answer:

hope it helps..

Explanation:

Number of protons

More information: The atomic number is used to identify an element, and the atomic number is the number of protons in the nuclei of an element. Every element has its own unique number of protons, and therefore, atomic number.

Is the solution a heterogeneous mixture?

Answers

Answer:

nope homogeneous

Explanation:

hope this helps :)

Answer:

SOLUTIONS are homogeneous mixtures. A solution is a mixture of two or more substances in a single phase.

Now look closely at the patterns in the table. Compare the elements in each column and row. What can we say about
elements in the same group and elements in the same period of the periodic table?
Select all the correct answers.
The number of electrons in the second energy level increases by one down each column.
Elements in the same row have the same number of occupied energy levels.
For each column, the last occupied energy level has the same number of electrons.
The number of electrons in the first energy level increases by one from Li to Ne.

Answers

Answer: Elements in the same row have the same number of occupied energy levels. For each column, the last occupied energy level has the same number of electrons.

Explanation: Straight from PLATO.

On comparing the elements we can say that:

B. Elements in the same row have the same number of occupied energy levels.

Elements in periodic table:

In the periodic table, elements are arranged in an order of increasing atomic number. It comprises of seven periods and eighteen groups.

The elements present in the same row or in the same period will have equal number of energy levels or shells.

Thus, option B is correct.

Find more information about periodic table here:

brainly.com/question/15987580

How much energy is needed to turn 450 g of zinc into liquid metal at its melting point? (Round your answer to the nearest tenth) *

Answers

Answer:

Explanation:

Latent heat of fusion of zinc = 7.322 kJ / mol

molecular weight of zinc = 65 g

450 gram = 450 / 65 = 6.92 mole

Heat required to melt 450 g of zinc = 6.92 x 7.322 kJ

= 50.67 kJ .

= 50.7 kJ .

List harmful effects of global warming? PLZZ HELP WHOEVER IS FIRST ILL MARK BRAINLEIST

Answers

Answer:

first theres the poliution  one of the biggest things thats starts global warming then theres recycle and non recycle because people mix there trash up when their not suppossed to.

Explanation:

a student is using colored beads to make a model of aluminum sulfate, Al2(SO4)3.
Aluminum atoms are represented by green beads, sulfur atoms by blue beads, and
oxygen atoms by yellow beads. What combination of beads should the student use for
the model?

Answers

The combination of beads should the student use for  the model :2 green, 3 blue and 12 yellow

the modelFurther explanation

In the chemical formula of a compound there are numbers:

1. The number indicates the number of atoms written after the element symbol

2. The number after the parentheses represents the number multiplied by the number of atoms in parentheses.

3. The number before the chemical formula shows the number of molecules behind it, which is usually used in equations

To calculate the beads needed to make a model, we must count the number of atoms of the Al₂(SO₄)₃ molecule

In the Al₂ (SO₄) ₃ molecule there are 3 atoms : Al, S, and O

1. Number of Al atoms: 2 2. The number of atoms S = 3 x 1 = 3 3. The number of atoms O = 4 x 3 = 12

So the combination of beads

2 green(for Al), 3 blue(for S) and 12 yellow(for O)

Answer:

2 blue, 3 yellow, and 12 green

Explanation:

Other Questions
Solve for x and y in the diagrams below. Which energy transformations occur when a candle burns?Thermal energy transforms into mechanical energy and radiant energy.Chemical energy transforms into thermal energy and electrical energy.Thermal energy transforms into radiant energy and chemical energyChemical energy transforms into thermal energy and radiant energy. Fill in the sentence with the correct form of the underlined word.We took a vote to elect our class president.We had an _________ 28. Simplitya) 4x + 2x pls help :D Use two colors to type your answers PART 1: Read the article Differences Between Modern and Ango-Saxon Values by Fred C. Robinson and determine the comparisons he is making between the two sets of values for each of the subheadings. Type the information that you get directly from Robinsons article in blueComparisonPointDetails about Anglo-Saxon ValuesModern ValuesLove andFriendshipShameCultureThe GivingOf GiftsThe Concept of FatePART 2: After you finish reading and filling in the details that come directly from Robinsons article, go back to the chart and look for any gaps or anything that the author left out. Based on your own knowledge, fill in the gaps, what was left unstated, or information that the author assumes readers will complete themselves. Fill in the information that you supply yourself in RED.What assumptions is the writer making about the audience for this article? (Answer here.) Luis and Raul are riding their bicycles to the beach from their respective homes. Luis proposes that they leave their respective homes at the same time and plan to arrive at the beach at the same time. The diagram shows Luis's position at two points during his ride to the beach. Write an equation in slope-intercept form to represent Luis's ride from his house to the beach. If Raul lives 5 miles closer to the beach than Luis, at what speed must Raul ride for the plan to work?If x represents the time in hours since the ride began and y represents the remaining distance from the beach, then the equation _____represents Luis's ride from his house to the beach. What is an indicator? What does it tell you about solutions? What was the first elective governing body in aBritish colony? still need help on this :/ ill just give extra points every time i post these.. what is the expression -3(4k-8) simplified Which of the following is an example of aset of like terms?a. {197, 19,y}b. {18x, -X, 21x}c. {15, 20, 25y}d. {-2x, -2y, -2xy) some children were paid as little as _________ per day to work.A. $1.00 one dollarB . $2.50 two dollars and fifty centsC. $.40 forty centsorD. $.75 seventy five cents Take these points but pls answer my other question:https://brainly.com/question/18304671 or go to my acc and my questions. YALLL PLZZZZ HELPPPP ANYBODYYYYY I DONT GET THIS We discussed the debt situation in the US and referred to the 'US mysteries' . Write an essay explaining these mysteries and why, the US is in a unique position relative to the rest of world. Make sure your answer includes a discussion of exorbitant privilege and 'dark matter.' Complete your essay with a discussion of why some are worried about the sustainability of this unique position and what the consequences would be on the US economy if we lost this 'unique position.' LESSON 5: Rational Numbers LEARNING TASK # 2 Score__________ Name:Joseph Sebastian Usi Section:7-Callalily Direction: Perform the indicated operations. 1.34+914=____221_____________ 2. 16+34=______45___________ 3. 46+418=_________220________ 4. 45-615=2 ________________ 5. 25-36=_________________ 6. 37 x 45=_________________ 7. 58x (-53)=_________________ 8. 3425=_________________ 9. 910(-45)=_________________ 10. 367 x 225=_________________ what are the intercepts of 3x -4y=-24 how are electrons arranged in elements with atomic numbers 1 through 10? How did the Northwest Ordinance of 1787 provide for the orderly expansion of the United States? what does the old woman's advice suggest about the theme,central idea, or myth