Select the correct answer from the drop-down menu. a scientist digs up sample of arctic ice that is 458,000 years old. he takes it to his lab and finds that it contains 1.675 grams of krypton-81. if the half-life of krypton-81 is 229,000 years, how much krypton-81 was present when the ice first formed? use the formula n = n0 . the ice originally contained grams of krypton 81.

Answers

Answer 1

The original mass of krypton 81 that is present in the ice is 6.70 grams.

How do we calculate original mass?

Original mass of any substance will be calculated as below for the decomposition reaction is:

N = N₀(1/2)ⁿ, where

N = remaining mass of krypton-81 = 1.675g

N₀ = original mass of krypton-81 = ?

n will be calculated as:
n = T/t, where

T = total time period = 458,000 years

t = half life time = 229,000 years

n = 458,000/229,000 = 2

Now putting all these values on the above equation, we get

N₀ = 1.675 / (1/2)²

N₀ = 6.70 g

Hence required mass is 6.70 g.

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Related Questions

a
Scientists have observed that the average surface temperature of the Earth has been increasing. This increase has
affected the oceans. Glaciers and ice sheets melt, and water from this melting process becomes part of the oceans.
The increasing temperature of the Earth's surface also warms ocean waters. As a result, the volume of the oceans
expands. These two events affect sea level.
What would happen to sea level if the average surface temperature trend that was observed since the 1960s
continues?
A) Sea level will rise, then will suddenly fall.
B) Sea level will remain the same.
C) Sea level will continue to fall.
D) Sea level will continue to rise.
Please select the best answer from the choices provided
O A
OB
Save and Exit
Next
Submit
Mark this and return

Answers

Answer:

D) Sea level will continue to rise

which of the following changes different colours in alkalis,acids,and neutral substances?

A red litmus paper
B Blue litmus paper
C universal indicator
D all of the above​

Answers

B I think if not it’s for sure a
A and B I think we did some experiments in chemistry but I don’t remember.

Which two organisms are most likely to be competitors?

chipmunk, cow
snake, hawk
snake, badger
chipmunk, badger

Answers

Chipmunk, badger I believe

what are the products for the following equation?

ZnBr2 + F2 -> ​

Answers

Answer:

The products to ZnBr2 + F2 -> Znf + Br2

When we balance this equation we get the following:

2ZnBr2 + F2 -> 2Znf + 2Br2

Hope this helps !!!

Pots A and B both have plain soil, bean seeds, and the same amount of light. Pot B receives more water (see table). After 50 days the plants are measured. Based on the data, which of the following conclusions can NOT be drawn from the data table?




A plant that receives more water will have more mass

The amount of water a plant receives affects its growth

The taller a plant is, the more mass it has

A plant that receives more water will grow t

Answers

A. water per day: 20 m/ height: 24cm/ mass: 3.1g B. Water per day: 60 ml/ height: 24cm/ mass: 9.6g

I think that the answer to this question is the third option. These two plants are of the same height but plant B has more mass. So therefore the statement is not true.

If this is a multiple-choice, then I would also select the fourth option along with the third. Plant B received more water, but it is the same height as plant A.

I hope my answer is satisfactory, and that I was of help to you.

-Toremi

What are 3 types of insects that belong to Phylum ?

Answers

Answer:

3 examples are beetles, a fly, and bees. Others include ants lady bugs and butterflies

Explanation:

Please, I need this now.
Drag each label to the correct location on the image.
Match each situation to the circuit diagram that represents it.

Answers

Answer: if anyone needs it <3

Explanation:

PLEASE HELPPPPP I WILL GIVE BRAINLIEST!!!!!
How many grams of ammonium sulfate can be produced if 2500.0 g of H2SO4 react with excess NH3 according to the equation 2NH3(aq) + H2SO4(aq) → (NH4)2SO4(aq)? Calculate the percent yield if 3100 g (NH4)2SO4 were actually produced.
-Calculate the theoretical yield of ammonium sulfate.
-Calculate the percent yield for the associated question
-Write the unit for the theoretical yield (see related question)

Answers

If 2500 grams of H2SO4 react with excess NH3 according to the illustration, the amount of ammonium sulfate that can be produced would be 3,370.92 grams. If only 3100 grams of ammonium sulfate were produced, the percentage yield would be 91.96%.

Stoichiometric calculations

From the equation of the reaction:

2NH3(aq) + H2SO4(aq) → (NH4)2SO4(aq)

The mole ratio of H2SO4 and (NH4)2SO4 is 1:1

Mole of 2500 grams H2SO4 = 2500/98 = 25.51 moles

Equivalent mole of (NH4)2SO4 = 25.51 moles

Mass of 25.51 moles (NH4)2SO4 = 25.51 x 132.14 = 3,370.92 grams

If 3100 g of (NH4)2SO4 were actually produced, the percentage yield would be:

Percent yield = 3100/3370.92 x 100 = 91.96%

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A(n) reaction is a self-sustaining series of chemical reactions in which the products of one reaction are the reactants in the next reaction.

Answers

The reaction which is a self-sustaining series of chemical reactions in which the products of one reaction are the reactants in the next reaction is chain reactions.

What are reactants and products?

Reactants are those species which are present at the initial state of the reaction and at the end of the reaction we obtain products.

If in any chemical reactions, reactants are combined for the formation of products and for the further process obtained product will act as reactant and that chemical reactions are known as chain reactions. Because this process continues for long time.

Hence correct option is chain reactions.

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Answer:

chain

Explanation:

edge 2023

sodium oxide can react with water to produce sodium hydroxide. in the reaction, how many moles of sodium hydroxide will be produced.

Answers

Answer: 2 mol of NaOH

Explanation:

The balanced chemical equation for the reaction is:

Na2O + H2O --> 2NaOH

Looking at this, we can see that 1 mol of Na2O will react with 1 mol of H2O to produce 2 mol of NaOH

please help I'm stuck on this!
What effect does sunlight have on CO2 molecules?

Answers

The Sun! The energy from light causes a chemical reaction that breaks down the molecules of carbon dioxide and water and reorganizes them to make the sugar (glucose) and oxygen gas.

Answer:

Carbon Dioxide is not affected by sunlight. But the radiation changes direction when it hits a carbon dioxide molecule

Explanation:

Which list of phases of H2O is arranged in order of increasing entropy

Answers

Answer: Solid, liquid, and gas are the three phases of H2O that are listed in order of increasing entropy.

The haphazard motion of water molecules in molecular water gives it the maximum flexibility.

state 3 commercial uses of oxygen​

Answers

Answer:

Brainliest Please !!!!!

Is god real I don’t really no but say yes

Answers

Answer:

Yes

Explanation:

We have been created by him therefore we would not have been created if there was no God.

Using the notation just described, represent a cell based on the following reaction:

ClO3−(aq)+3Cu(s)+6H+(aq)→Cl−(aq)+3Cu2+(aq)+3H2O(l)

Pt is used as an inert electrode in contact with the ClO3− and Cl− .

Drag the appropriate labels to their respective targets. For neutral species, leave the pink target blank.

Answers

The cell notation of the redox reaction between Cu and ClO₃⁻ is:

Cu/Cu²⁺//ClO₃⁻//Cl⁻/Pt

What is a voltaic cell?

A voltaic cell or electrochemical cell is a device which produces electricity from chemical reactions occuring within the cell.

The reactions occuring in a voltaic cell are redox reactions.

Oxidation occurs at the anode while reduction occurs at the cathode.

In the given reaction between Cu and ClO₃⁻ as shown below:

ClO₃⁻ (aq) + 3 Cu (s) + 6H⁺ (aq) → Cl⁻ (aq) + 3 Cu²⁺ (aq) + 3 H₂O (l)

Cu is oxidized as follows: 3 Cu (s) → 3 Cu²⁺
ClO₃⁻ is reduced as follows: ClO₃⁻ (aq) → Cl⁻ (aq)

The voltaic cell notation is as follows where Pt is used as an inert electrode in contact with the ClO₃⁻ and Cl⁻:

Cu/Cu²⁺//ClO₃⁻//Cl⁻/Pt

Therefore, the cell notation of the redox reaction between Cu and ClO₃⁻ shows that Cu is oxidized while ClO₃⁻ is reduced.

Leran more about voltaic cells at: https://brainly.com/question/3930479

4. What is the movement of blood through your blood vessels called?
circulation
digestion
nervous

Answers

Answer:

circulation

Explanation:

The movement of the blood through the heart and around the body through the narrow vessels is called circulation which makes up the cardiovascular system.

Answer:

Circulation

Explanation

digestion is the process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body and its the only one that makes sence

A 6.39L balloon filled with gas is warmed from 239.3K to 305.9K. What is the volume of the gas after it is heated?

Answers

Answer:

69.271837183727718371

1. In sheep, a gene with two alleles decides wool color. The allele for white wool is

dominant to the allele for black wool. If two heterozygous sheep mate, what

percentage of the sheep will have white wool? Record your answer as a

percent.

White wool

Black wool

HINT: Create a Punnett square on scratch paper to determine the answer.

Answers

The percentage of the sheep which will have white wool is 75 percent.The percentage of the sheep which will have black wool is 25 percent.

What is an Allele?

This is defined as a variant form of a gene. We were told that allele for  white wool is dominant to the allele for black wool and two heterozygous sheep mated.

When we cross Ww and Ww we get WW, Ww, Ww, ww. Since white is dominant then the percentage is 3/4 = 75 percent.

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Anyone know this? Cuz I don’t this one is

Answers

Answer:

its legislative.

help me with this pleaseeeeeee

Answers

Magnesium oxide is an ionic compound with a very high melting point and which requires a large amount of energy for melting.

What are ionic compounds?

Ionic compounds are compounds which are formed between oppositely charged ions which are held together by electrostatic forces of attraction between the oppositely charged ions.

Ionic compounds are formed when metal atoms donate electrons to non-metals atoms to form ions.

Magnesium oxide is an ionic compound.

The nature of bonding is ionic bonding.

It has a crystalline lattice structure.

The forces of attraction is electrostatic forces of attraction.

It has a high melting point of 2,852 °C, and thus requires a large amount of energy go melting to occur.

Therefore, magnesium oxide is an ionic compound which requires a large amount of energy for melting.

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two protons are placed 1 mm apart. separately two electrons are placed 1 cm apart. which pair will have greater force between them​

Answers

Answer:

The protons

Explanation:

The force of attraction/repulsion is indirectly proportional to the square of the distance between...the protons are much closer together and will have a stronger force.

F = k q1q2 / r^2

Which of the following helps explain why experiments involving speed and velocity are important? (1 point)
Experiments involving speed and velocity are important because they have not been investigated much and scientists still do not fully understand how speed and velocity are related
Experiments involving speed and velocity are not important because they have already been thoroughly investigated by scientists and there is nothing more to learn.
Repeated experiments with airplanes and how their velocity changes as a result of environmental conditions like wind can help scientists develop a model for flight paths and launch times to
minimize fuel usage
O Repeated experiments that change motivational foods for tortoises on tracks can help scientists determine preferred eating habits

Answers

The statement that explain the important of experiment with speed and time is

Repeated experiments with airplanes and how their velocity changes as a result of environmental conditions like wind can help scientists develop a model for flight paths and launch times to minimize fuel usage.

What is an experiment?

An experiment is a scientific procedure or technique carried out in a place to discover or test the validity of something.

Velocity refer to the rate of change of body's position and direction in respect to time.

Speed is the distance travel by an object in respect to time.

Therefore, The statement that explain the important of experiment with speed and time is

Repeated experiments with airplanes and how their velocity changes as a result of environmental conditions like wind can help scientists develop a model for flight paths and launch times to minimize fuel usage.

Learn more about experiment below.

https://brainly.com/question/25303029

What is the name of an isotope with 23 protons and 25 neutrons?
Select one:

Cadmium

Vanadium

Chromium

Manganese

Answers

Answer: Vanadium

Explanation:

Based on the Law of Conservation of Mass, what's the minimum amount of Magnesium that will react with 32g of Oxygen to produce 80.6g of Magnesium Oxide?​

Answers

mass before reaction = mass after reaction

Mg + O = MgO

Mg + 32 = 80.6

Mg = 80.6 - 32 = 48.6 (a)

How many moles of lead chloride pbCl2, will be produced if 10.0 moles of Orion chloride FeCl33 reacted

Answers

Answer:

0.72 moles of hydrochloric acid are needed to completely react with 0.36 mol of lead.

Explanation:

I hope this helps you! :)

In 1-2 sentences, describe what happens to atoms of a compound when a chemical reaction occurs​

Answers

In a chemical reaction, bonds between atoms in the reactants are broken and the atoms rearrange and form new bonds to make the products.

The atoms get rearranged into new substances.

What’s the answer for this?

Answers

Answer:

it will fall then rise and return to ×

complete and balance the following equation b. Br2 + Nacl​

Answers

Br2 + 2NaCl —> 2NaBr + Cl2

How many moles of water (H20) are produced when 2 moles of KMnO, react with plenty of HCI? Show work if can will give most points :) !!

Answers

I hope this helps, you can ask any questions for clarification

Question 6 of 10
What does it mean when a reaction is spontaneous?
O
A. The reaction requires added energy.
B. The reaction goes to completion.
C. The reaction occurs rapidly.
O O
D. The reaction happens by itself.
SUBMIT

Answers

Answer:

D

Explanation:

Does not require energy ...may be slow or fast....

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