How much of a 0.74mg sample of uranium-235 will remain after 2.8x10^9

Answers

Answer 1
of Uranium-235 remains after 2.8 x 10^9 years, what was the original mass of the sample of Uranium-235? The half-life of Uranium-235 is 7.0 x 10^8 years. Uranium-232 has a half life of 68.8 years.

Related Questions

2.(05.05 LC)
A chef is serving a lunch special with 1 sandwich and 2 corn cobs per plate. If there are 5 sandwiches and 14 com cobs, what is the theoretical yield? (3 point
O 2 plates
4 plates
5 plates
O 7 plates

Answers

Answer:  5 plates

Explanation:

Because you have 5 sandwiches total

5 plates are the theoretical yield. Hence, option C is correct.

What is a theoretical yield?

The theoretical yield is the maximum possible mass of a product that can be made in a chemical reaction.

The actual yield is the result obtained from the experiment while the theoretical yield is the result obtained from our calculations.

The actual yield of a chemical reaction rarely equals the theoretical yield because some of the amounts are lost during the process.

5 plates are the theoretical yield.

Hence, option C is correct.

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Which of the following is NOT a good way to manage stress?

eat a healthful diet.


get enough sleep.


get plenty of exercise.


spend most of the time alone.

2. Which systems receive a benefit from the nervous system?



Digestive


Respiratory


Skeletal


Muscular


Cardiovascular (circulatory)

Answers

Answer:

spending most of the time aloneSkeleton

what is love?
A)don't hurt me
B)don't hurt me
C)No more

Answers

Answer:

C

Explanation:

I think it is a ever lasting process of pain and happiness cause the ones that are closest to you can make it hurt most but they can also make your day So probably

What would a chemist most likely study about a car?

Answers

Answer:

I believe it's the chemical composition of the fuel and different fluids such as the coolant of the radiator

Explanation:

Chemists may discover more sustainable compounds that produce less waste material or that release more energy for the least amount of fuel. For coolants, fluids with greater heat retention that can absorb heat and direct it to the radiator in the most efficient manner. This is usually paired with engineering.

Read the given equation:
Ca(OH)2 + 2HCl - CaCl2 + 2H20
Which of the following is true about the equation? (5 points)
HCI is the base and Ca(OH)2 is the salt.
HCI is the acid and Ca(OH)2 is the salt.
Ca(OH)2 is the acid and Cacl2 is the salt.
Ca(OH)2 is the base and CaCl2 is the salt.

Answers

Answer:

D.

HCl is acid

Ca(OH)2 is base

CaCl2 is salt

In the given chemical equation Ca(OH)2 is the base and CaCl2 is the salt, thus  option D is correct.

What is chemical equation?

A chemical equation is a symbolic representation of a chemical reaction that shows the products, reactants, and direction of the reaction.

An acid is any hydrogen-containing substance that is capable of donating a proton (hydrogen ion) to another substance.

A base is a chemical species that donates electrons, accepts protons, or releases hydroxide (OH-) ions in aqueous solution.

A salt, in chemistry, is defined as the product formed from the neutralisation reaction of acids and bases.

Therefore,  in this chemical  equation  option D is true about the equation i.e

Ca(OH)2 is the base and CaCl2 is the salt.

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If this block has a mass of 173.7 grams, then what is this element??

Answers

Answer:

C

I am pretty sure that is the answer

The mass of the given cube of 173.7g and the volume of the box is 9 cm³.Then the density is 19.3 g/cm³. Therefore, the element with this density is gold. Option D is correct.

What is density?

Density of a substance is the ratio of mass to its volume. Thus it tells about how much denser the substance is in the given volume. This physical quantity is dependant on mass, volume temperature and pressure.

The element have their own density corresponding to the mass and volume used. The dimensions of the given box is 3, 3 and 1. Thus volume is the product of this length, breadth and height.

Volume = 3 ×3 × 1

             = 9 cm³.

Mass of the box is given 173.7 grams. Now, the density of the element is calculated as follows:

Density = 173.3 /  9 cm³

             = 19.3 g/cm³.

From the table, it is clear that the this density corresponds to the element gold. Therefore, option D is correct.

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3.) which organic compound has 4 carbon atoms with at least one triple bond?

O butyne
O butene
O butane
O pentyne

Answers

The answer is butene

How do scientists gather information about climate conditions millions of years ago?

Answers

Answer:

Paleoclimatology

Step by Step explanation:

is the study of climate records from hundreds to millions of years ago. Information for paleoclimate studies come from natural records rather than instruments: these indirect records of climatic conditions are called proxy records. Coring a tree to gain access to tree ring data.

how to sold equation with periodic table of elements?​

Answers

Answer:

6w6288shbdmdkdhckcncjciicjcididjdn dmxixisk ddjdidjjd

Explanation:

dnnxjxkxjxjndnfncjcshndnsbsnnsnssbsnsnsnsndndndnx

The diagram above shows the repeating groups of atoms that make up two samples. Will the
properties of the two samples likely be the same or different? (Examples of properties are smell,
color, and the temperature at which a substance melts.)
a
The properties will likely be different because the repeating groups of atoms that make up
each sample are different.
b
The properties will likely be different because there are more repeating groups of atoms in
Sample 2.
c
The properties will likely be the same because the repeating groups of atoms that make up
the two samples have the same number of atoms.
d
The properties will likely be the same because the repeating groups of atoms that make up
the two samples have two of the same types of atoms.​

Answers

Yes it’s d yes yes yes

CH4+xO2=CO2+2H2O. Find x

Answers

Answer:

x = 2, [tex]CH_{4} + 2O_{2} = CO_{2} + 2H_{2}O\\[/tex]

Explanation:

This question is related to balancing chemical equations.

[tex]CH_{4} + xO_{2} = CO_{2} + 2H_{2}O\\[/tex]

- There must be the same amount of carbons (C), hydrogens (H), and oxygens (O) on each side of the equals sign.

- There is already 1 carbon and 4 hydrogens on each side of the equals sign. The big number in front of the chemical compound multiplies into the individual elements and can be multiplied by the subscripts to get the total number of each element.

- On the right side of the equation, there are 4 oxygens (O), and on the left side, there are 2. In order for there to be 4 oxygens (O) on the left side, there must be a 2 in front of [tex]O_{2}[/tex].

Therefore, x = 2.

[tex]CH_{4} + 2O_{2} = CO_{2} + 2H_{2}O\\[/tex]

propose 3 solutions that address that sources of global warming

Answers

Answer:

The correct answer is - reduce carbon emission, decrease deforestation snd increase plantation, use renewable energy.

Explanation:

Global warming is the process that is caused by human activities to increase the temperature of the earth. It increases the heat of the climate of the earth that leads to a negative impact on the environment. Increasing the greenhouse gas emission leads to trapping heat and cause global warming.

The three major solutions are:

1. reduce carbon and greenhouse gases: The main cause of global warming is the emission of greenhouse gases and an increase in carbon in the atmosphere, so reduce these gas emissions by avoiding fossil fuels that release carbon.

2. reduce deforestation and increase the plantation: trees take carbon dioxide from the environment, So prevent them from cutting and planting new trees will help reducing carbon from the environment.

3. Using renewable energy will help them to not depend on fossil fuels or water waste that will help in reducing global warming.

(05.06 MC)

During an experiment, the percent yield of calcium chloride from a reaction was 85.22%. Theoretically, the

expected amount should have

grams What was the actual yield from this reaction? (5 points)

CaCO3 + HCI - CaCl2 + CO2 + H20

been 113

96.3 grams

О 99.0 grams

113 grams

0 121 grams

Answers

Answer:

96.3g is the actual yield from this reaction

Explanation:

Have been 113g...

The percent yield of a reaction is defined as one hundred times the ratio between actual yield (Our incognite) and the theoretical yielf (113g). The equation is:

Percent yield = 85.22% = Actual Yield / 113g * 100

0.8522 = Actual Yield / 113g

0.8522*113g =

96.3g is the actual yield from this reaction

Answer:

96.3

Explanation:

Just took the test

What is the main purpose of phloem tissue?

to carry food from the leaves to all the cells of the plant
to absorb water and minerals from the soil
to store extra food for the plant to use in the winter
to carry water and minerals from the roots to the lea

Answers

Plants have tissues to transport water, nutrients and minerals. Xylem transports water and mineral salts from the roots up to other parts of the plant, while phloem transports sucrose and amino acids between the leaves and other parts of the plant.

Can someone please help me on this

Answers

Answer:

it's none because the graph is decreasing like a milf so that why


What quantity of energy would be necessary to boil water with a mass of
123 g that is at 100.00°C ?

Answers

Answer:

i think 554 I think

Explanation:

maybe ..

Which area of science is considered the central science?
chemistry
biology
physics
environmental science

Answers

Answer:

Chemistry

Explanation:

Chemistry is considered the central science.

Which area of science is considered the central science?

Chemistry is sometimes called "the central science" because it's so important to other fields of science, like biology, geology, astronomy, physics, medicine, engineering, materials science, and many other areas of study.

Which branch of science is the most important?

All the branches of science possess their own level of importance, However, physics deals with the fundamental workings of material reality which are central to all other branches of science.

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Silver nitrate is reacted with magnesium bromide and two products are formed.
(Ignore selected answer)

Answers

Answer:

The correct answer is :

         a silver nitrate solution (AgNO3) is mixed with a solution of magnesium bromide (MgBr2). The balanced reaction would be: 2 AgNO3(aq) + MgBr2 --> 2 AgBr + Mg(NO3)2

the last one

CI2+NaOH⇒NaCI+NaOCI+H20
is there a way to balance this?

Answers

I really don’t think so…

An isotope undergoes radioactive decay. The new isotope that forms has an atomic number that is 2 less than the original isotope's.

Answers

Answer: The parent isotope is undergoing alpha decay.

Explanation:

A nuclear reaction is defined as the reaction in which the changes in the nucleus of an atom take place and usually form a different element. An unstable nucleus undergoes various decay processes to attain stability.

Alpha decay is a type of decay process that happens when a heavy nucleus decays into a light nucleus with the release of an alpha particle. This alpha particle carries a charge of +2 units and has a mass of 4 units. It is also known as the helium nucleus. The general equation for this decay process is:

[tex]X_Z^A\rightarrow Y_{Z-2}^{A-4}+\alpha _2^4[/tex]

It is given that the daughter isotope formed has atomic number 2 less than the parent isotope. Thus, it is undergoing alpha decay.

Answer:

alpha decay because alpha particles have two protons and two neutrons

Explanation:

Edge

Write a hypothesis using IF-THEN - BECAUSE of statement. (PLEASE HELP)
Ahmed is curious about the death of the fishes in the ocean. He knows from his environmental chemistry class that pollutants like heavy metals can cause the rapid death of marine organisms. So, Ahmed did an experiment and obtained water samples. He tested that water contains a high amount of lead and chromium.

Answers

Water is an essential part of life and its availability is important for all living creatures. On the other side, the world is suffering from a major problem of drinking water. There are several gases, microorganisms and other toxins (chemicals and heavy metals) added into water during rain, flowing water, etc. which is responsible for water pollution. This review article describes various applications of nanomaterial in removing different types of impurities from polluted water. There are various kinds of nanomaterials, which carried huge potential to treat polluted water (containing metal toxin substance, different organic and inorganic impurities) very effectively due to their unique properties like greater surface area, able to work at low concentration, etc. The nanostructured catalytic membranes, nanosorbents and nanophotocatalyst based approaches to remove pollutants from wastewater are eco-friendly and efficient, but they require more energy, more investment in order to purify the wastewater. There are many challenges and issues of wastewater treatment. Some precautions are also required to keep away from ecological and health issues. New modern equipment for wastewater treatment should be flexible, low cost and efficient for the commercialization purpose.

Why does air density decrease with increasing altitude within Earth's atmosphere?

Answers

Explanation:

As the altitude increases, the pressure and the density of the atmosphere decrease.

Which half-reaction shows conservation of charge? * 5 points A) Cu + e– → Cu+ B) Cu2+ + 2e– → Cu C) Cu+ → Cu + e– D) Cu2+ → Cu + 2e–

Answers

Answer:

B) Cu2+ + 2e– → Cu.

Explanation:

Hello there!

In this case, in the regard of redox reactions, we must keep in mind that half-reactions show us how the flow of electrons when an element undergoes a change in its oxidation state, say increasing or decreasing. In such a way, if the element is oxidized, increase the oxidation state, we add electrons on the right side and the contrary if the element is reduced, decrease the oxidation state.

In such a way, we can see that the reaction B) Cu2+ + 2e– → Cu, shows how the Cu2+ cations are reduced by adding electrons to produce Cu and thus, conserve the charge.

Best regards!

two advantage of tourist industry?​

Answers

Explanation:

                 Two advantage of Tourist Industry:

Tourism is one of the largest and fastest growing industry in terms of generating more revenues, providing Large number of employment opportunities and only one major ways to development the nation within short spam of time. There are so many facts that, tourism helps making the country renowned all over the world and is called only one weapon to make country strong as from all the aspects.

Although, as we all know that, there are several facts and data's which shows that tourism is only one largest industry throughout world that generated huge amounts of Money than others. So what are the advantages of tourism? Which can be pointed out as following :-

1. Tourism helps to generate more revenues in the country.

2. The tourism can change the nation within a short time period.

3. Tourism helps to provide more numerous kinds of human resources in the nation.

4. Tourism is only one way to develop and to make renowned in the world

ASAP:
The estimated atomic mass of silicon could be Choose... amu because the Choose.. abundant isotope is Choose...​

Answers

Answer:

The estimated atomic of silicon is 28.082 a.m.u.

Explanation:

The estimated atomic mass of silicon ([tex]M_{Si, est}[/tex]), in a.m.u., is equal to the weighted average of atomic masses of silicon available in nature and in terms of their abundances:

[tex]M_{Si, est} = r_{1}\cdot M_{Si-28} + r_{2} \cdot M_{Si-29} + r_{3}\cdot M_{Si-30}[/tex] (1)

Where:

[tex]r_{1}[/tex], [tex]r_{2}[/tex], [tex]r_{3}[/tex] - Relative abundance of each isotope, no unit.

[tex]M_{Si-28}[/tex], [tex]M_{Si-29}[/tex], [tex]M_{Si-30}[/tex] - Atomic mass of each isotope, in a.m.u.

If we know that [tex]M_{Si-28} = 27.976\,a.m.u.[/tex], [tex]M_{Si-29} = 28.976\,a.m.u.[/tex], [tex]M_{Si-30} = 29.974\,a.m.u.[/tex], [tex]r_{1} = \frac{92.22}{100}[/tex], [tex]r_{2} = \frac{4.68}{100}[/tex] and [tex]r_{3} = \frac{3.09}{100}[/tex], then the estimated atomic mass of silicon is:

[tex]M_{Si, est} = r_{1}\cdot M_{Si-28} + r_{2} \cdot M_{Si-29} + r_{3}\cdot M_{Si-30}[/tex]

[tex]M_{Si,est} = \left(\frac{92.22}{100} \right)\cdot (27.976\,a.m.u.) + \left(\frac{4.68}{100} \right)\cdot (28.976\,a.m.u.) + \left(\frac{3.09}{100} \right)\cdot (29.974\,a.m.u.)[/tex]

[tex]M_{Si, est} = 28.082\,a.m.u.[/tex]

The estimated atomic of silicon is 28.082 a.m.u.

Which of the following statements is true for all eukarya?
Group of answer choices

A. their cells contain a nucleus.

B. their cells do not contain a nucleus.

C. their cells do not contain a nucleus and they have a different cell wall from bacteria.

D. their cell do not contain a nucleus and they have a similar cell wall when compared to bacteria.

Answers

Answer:

A. their cells contain a nucleus

Explanation:

hope it helps

please mark me as a brainliest


Which of the following best describes Avogadro's number?*
A) An equation that can be used to calculate how many atoms are in one mole of
anything
B) A variable that represents the value of the atomic mass relative to one mole of an
element
C) A constant that states how many atoms/molecules are in one mole of anything
D)An expression in scientific notation that represents the average atomic mass of an
element

Answers

Answer:

C) A constant that states how many atoms/molecules are in one mole of anything

Explanation:

Avogadro's number like the name suggests is a constant that states how many atoms/molecules are in one mole of anything.

Question 2 of 10. What is Diffusion?​

Answers

Answer:

diffusion: the movement of molecules in a solution from an area of

higher concentration to an area of lower concentration

Diffusion is the movement of particles from where there are more to where there are less. This movement occurs until particles are evenly spread out. While diffusion can be seen in all states of matter, it is most common in liquids and gases.

NaOH+ N2O3---> ___+____​

Answers

Answer:

NaOH+ N2O3---> NaNO2 + H2O

Please help me quick I have to get this right


the following question represents a

A)-weak acid
B)-strong acid
C)-weak base
D)-strong base

Answers

Answer:Any acid that dissociates 100% into ions is called a strong acid. If it does not dissociate 100%, it is a weak acid.

Explanation:acid. (d) Water can act as a Brønsted-Lowry base. ... (b) Give the conjugate acid of the following Brønsted-Lowry bases: ... 16.21 Label each of the following as being a strong base, a weak base, or a species with ... (C) NH Weak base, Netyt is a weak acid ... CHz Lo0H is stronger acid than Hys, so equilibrinus lies to right.

If it’s one correct is weak base. If it’s two correct is weak and strong acid
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