The Environmental Protection Agency and health officials nationwide are concerned about the levels
of Radon gas in homes. The half-life of Radon-222 isotope is 3.8 days. If a sample of gas taken from
basement contains 4.38 ug of Radon-222, how long will it be until 0.55 ug will remain? How many half lives?

Answers

Answer 1

It takes 11.4 days⇒three half-lives

Further explanation

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

t1/2=3.8 days

No=4.38 μg

Nt=0.55 μg

[tex]\tt 0.55=4.38\dfrac{1}{2}^{t/3.8}\\\\0.125=\dfrac{1}{2}^{t/3.8}\\\\\dfrac{1}{2}^3=\dfrac{1}{2}^{t/3.8}\\\\3=t/3.8\rightarrow t=3.8\times 3=11.4~days[/tex]


Related Questions

What element is represented in this model of the atomic number is 3
This is science

Answers

Answer:

lithium because it has an atomic number of three(you could have just googled which element has the atomic number 3)

What does temperature measure in a sample of matter? A.The exact speed of the particles B.The average kinetic energy of the particles C.The average number of particles D.The exact atomic number of the particles


Plz answer

Answers

Answer: its B. The average kinetic energy of the particles.

Don’t trust the person above

Explanation:

I took the quiz and i got it right

A Temperature is a unit used to represent hotness or coolness on any of a number of scales, including Fahrenheit and Celsius. The direction that heat energy will spontaneously flow depends on temperature. The average kinetic energy of the particles is indicated by temperature. The correct option is B.

Temperature and heat are connected but distinct concepts. The average kinetic energy of a substance's particles is measured by its temperature. The kinetic energy of an object increases with its temperature. A sort of energy connected to motion is called kinetic energy.

The average kinetic energy of the particles in a substance is measured by temperature. The overall kinetic energy of the particles in a substance is measured by its thermal energy. The temperature and thermal energy of a substance increase with particle mobility.

Thus the correct option is B.

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Magnesium reacts with hydrochloric acid to produce hydrogen gas and magnesium chloride. What
volume of hydrogen gas is theoretically produced in cubic millimeters, if 4.9 g magnesium reacts
with excess hydrochloric acid? The reaction is taking place at 101.5 kPa pressure and 20°C.

Answers

using PV=mRT/Mr

V=(4.9×8.31×(273+20))/(24.3×101.5×10^3)

=4.84×10^-3 m^3

=4.84×10^6 mm^3

Need help please ! if someone can answer any of these that would be great !!

Answers

Answer:

NH4 ClBa Br2Al4 C3Na2 OK3 PO4Ca F2Li3 NBa CO3Al2 (SO4)3Mg (NO3)2Li2 SNa2 SO4Ca (HCO3)2Ag CH3 COOZn (OH)2

Explanation:

Here are all of them- your picture had #1-13, but here's #1-15!

What is the frequency of a photon with an energy of 3.38 x 10-19 J?​

Answers

Hey There!_____________________________________Answer:

[tex]\huge\boxed{5.1x[tex]10^{14}[/tex]Hz}[/tex]

_____________________________________DATA:

E = [tex]3.38 x 10^{-19}[/tex]

h = [tex]6.625x10^{-34}[/tex]

f = ?

_____________________________________SOLUTION:

Energy of Photon is given by,

                                   

                                   E = hf

Rearrange the equation,

                             

                                    f = [tex]\frac{E}{h}[/tex]

where,

           E = energy

           h = planck's constant

           f = frequency

------------------------------------------------------------------------------------------------------------

Substitute the variable in the equation,

 

                                 f = [tex]\frac{3.38x10^{-19}}{6.62x10^{-34}}[/tex]

Simplify the equation,

                               

                                  f = 5.10 x 10^14 Hz          

                         

_____________________________________Best Regards,'Borz'

Answer:

b. 5.10 x 10^14 Hz

Explanation:

List the 5 signs of a CHEMICAL REACTION

Answers

color change, formation of a precipitation, formation of a gas, odor change, temperature change

How does energy
change from
potential to
kinetic?

Answers

Answer:

An object has potential energy, stored energy, when it is not in motion. Once a force has been applied or it begins to move the potential energy changes to kinetic energy, or motion energy.

Good luck, hope this helped!

compare the two types of optical telescopes

Answers

Answer: Reflectors use a mirror to collect the light, whilst refractors use a lens while, Refractor telescopes require a large lens at the front to direct the incoming light to the lens.

Hey guys
What is ionic bond and how do we get it???
Please quik helpp

Answers

Answer:

Ionic bond, also called electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound. Such a bond forms when the valence (outermost) electrons of one atom are transferred permanently to another atom.

Explanation:

An animal cell placed in a hypertonic solution will shrink in a process called crenation. An animal cell placed in a hypotonic solution will swell and potentially burst in a process called hemolysis. To prevent crenation or hemolysis, an animal cell must be placed in an isotonic solution such as 0.9% (m/v) NaCl or 5.0% (m/v) glucose. This does not mean that a cell has a 5.0% (m/v) glucose concentration; it just means that 5.0% (m/v) glucose will exert the same osmotic pressure as the solution inside the cell, which contains several different solutes. A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur.
Solution A: 3.21% (m/v) NaCl
Solution B: 1.65% (m/v) glucose
Solution C: distilled H2O
Solution D: 6.97% (m/v) glucose
Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl
Drag each solution to the appropriate bin.

Answers

Answer:

Solution A: 3.21% (m/v) NaCl  ⇒ CRENATION

Solution B: 1.65% (m/v) glucose  ⇒ HEMOLYSIS

Solution C: distilled H₂O  ⇒ HEMOLYSIS

Solution D: 6.97% (m/v) glucose  ⇒ CRENATION

Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl ⇒ CRENATION

Explanation:

Isotonic solution = 0.9% (m/v) NaCl or 5.0% (m/v) glucose

Crenation will occur if the solution has a concentration higher than 0.9% (m/v) NaCl or 5.0% (m/v) glucose (hypertonic solution). This will occur in the following solutions:

Solution A: 3.21% (m/v) NaCl  > 0.9% (m/v) NaCl

Solution D: 6.97% (m/v) glucose  > 5.0% (m/v) glucose

Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl (the addition of the 2 components exceeds the osmotic pressure permitted).

Hemolysis will occur if the solution has a concentration lower than 0.9% (m/v) NaCl or 5.0% (m/v) glucose (hypotonic solution). This is the case of:

Solution B: 1.65% (m/v) glucose < 5.0% (m/v) glucose

Solution C: distilled H₂O = 0% glucose/0% NaCl < 0.9% (m/v) NaCl or 5.0% (m/v) glucose

Please help me it would be amazing if you can?
(NUMBER 9)

Answers

Answer:

3) Warm Temperature and High Pressure

Explanation:

I explained this in your other question ;)

Answer:

Warm temp and high pressure

Explanation:

What’s the answer????

Answers

Answer:

Greater

Greater

Explanation:

The amplitude of a wave is the height of the wave or the vertical displacement of the wave motion. We determine a wave amplitude usually by looking at the graph of the wave.

Amplitude is directly proportional to the energy of a wave. The higher the amplitude of a wave, the more its energy.

Frequency is the number of waves that passes a point at a particular instance of time. It is also directly proportional to the energy carried by a wave. The higher the frequency of a wave, the greater its energy.

Use the following to answer questions. Which of the following is/are not characteristic of an ionic compound?

I. Metal bonded to a nonmetal

II. Conducts electricity when dissolved in water

III. Called a ‘salt.’

IV. High melting point

V. Lattice structure

VI. Electrons are shared between elements

Group of answer choices

VI only

II, IV, and VI

I and III

II and V

Answers

Answer:

VI only

Explanation:

What is evidence that a chemical change has happened?
O A. The temperature of a substance increases or decreases.
B. The amount of matter increases.
C. A substance changes into a new kind of substance.
O D. You observe a color change.

Answers

i think the answer is D

dfgasfsadfasdfasdfasdfadsf

Answers

Answer:

fsdafdsafdsafdsafdasfsagfd

Explanation:

ehat coefficient would go in the box​

Answers

Answer:

1.nhl

Explanation:

Please help :) —————————————

Answers

Answer:

I can't see what the picture says

how is all the “stuff” around us matter is because it is made up of atoms?

Answers

Answer:

Matter is the Stuff Around You

Matter is everything around you. Atoms and compounds are all made of very small parts of matter. ... Matter is defined as anything that has mass and takes up space (it has volume).

Explanation:

hope it was helpful

1. Salt has the chemical formula NaCl because it is made up of atoms of Sodium (Na) and Chlorine (CI).
Which statement most accurately describes this compound in relation to the elements it is made of?
A. When sodium and chlorine chemically combine they create a substance with completely different
properties
B. Salt has similar properties to the sodium and chlorine it is made of
C. Once salt is formed the sodium and chlorine atoms no longer exist, only salt atoms
D. Salt can easily be separated back into sodium and chlorine atoms through physical means

Answers

Answer:

A

Explanation:

When Na atom chemically combine with with Cl atom to form NaCl both atoms loose their chemical properties due to the fact that Na atom transfer an electron to cl atom. after transfer of electron Na atom become Na ion (cation) and Cl atom become Cl ion (anion)

what is the needed electrons for CLO3-​

Answers

Each oxygen atom in the ClO3- ion already has two electrons the electrons in the Cl-O covalent bond. Because each oxygen atom needs six nonbonding electrons to satisfy its octet, it takes 18 nonbonding electrons to satisfy the three oxygen atoms.

Describe in your own words how the earth's layers were formed.

Answers

Answer:It starts from the centre.The inner core.The outer core.The mantle .And the crust.They formed as the building blocks of earth.Knownas planetesimals collided and collapsed under Thier own gravity around 4.5 billion years ago

The layers of the earth were formed due to the sediments that significantly flattens out beside the center of the earth. After a long duration, a new layer is spread over the older layer, and so on.

What are the different layers of the earth?

The different layers of the earth are as follows:

The Inner Core: This is the first layer from the center of the earth. The Outer Core: It is found after the inner core. The Mantle: It is the middle layer of the earth. The Crust: It is the outermost layer of the earth.

The above-mentioned layers of the earth were formed with the impact of the building blocks of the earth that are remarkably known as Planetesimals, collided, and collapsed.

During that time, the hardest elements like nickel, iron, etc. constitute the core while the lighter elements like carbon, oxygen, silicon, etc. play an essential role in the formation of crust and mantle.

Therefore, the layers of the earth were formed due to the sediments that significantly flattens out beside the center of the earth.

To learn more about The layers of the earth, refer to the link:

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Please help meee! It would be awesome if you can!

Answers

Answer:

3) the north Pacific Ocean

Explanation:

Maritime polar air is defined officially as: Maritime polar (mP) air masses are cool, moist, and unstable. Some maritime polar air masses originate as continental polar air masses over Asia and move westward over the Pacific, collecting warmth and moisture from the ocean

Basically it's the North Pacific Ocean because of the higher latitude and colder air temperature

H2O is polar covalent or its Hydrogen bond??? PLEASE HELP!!!

Answers

Answer:

Polar covalent.

Explanation:

The covalent bonds are therefore polar, and the oxygen atoms have a slight negative charge (from the presence extra electron share), while the hydrogens are slightly positive (from the extra un-neutralized protons). Opposite charges attract one another.

I WILLL GIVE YOU BRAINLYESTTT PLEASE HELPPPP

Answers

Answer:

10.99s

Explanation:

Given parameters:

Speed of the fly = 9.1m/s

Distance flown = 100m

Unknown:

Time taken to fly this distance = ?

Solution:

Speed is distance divided by the time;

  Mathematically;

            Speed  = [tex]\frac{distance}{time}[/tex]  

             Time  = [tex]\frac{distance}{speed }[/tex]  

Insert the parameters and solve;

        Time  = [tex]\frac{100}{9.1}[/tex]   = 10.99s

answer the question​

Answers

The answer is B your welcome

Helpppppp i hate chemistry
I will give brainiest who helps me with the correct answer
I promise

5. Name the compound which contain Strontium, Fluorine, and Oxygen.

Options:

Strontium fluorate
Strontium fluoride
Strontium chlorate
Strontium fluorine

Answers

Strontium fluorate.

what happens to the temperatures when we have direct sunlight vs indirect sunlight?

Answers

Explanation:

When we have direct sunlight, the temperature is higher compared to indirect sunlight.

Direct sunlight is usually overhead whereas indirect sunlight is at an angle to the surface.

Direct sunlight impacts the surface with more energy concentrated on a smaller surface area. This warms the surface more. Indirect sunlight is diffuse and spreads over a wider area. This leads to a reduction in temperature.

HELLPPP PLEASE. 50PTS
ITS URGENT


Ella wants to construct an electrochemical cell using the following materials :
1.Salt water (as electrolyte)
2.Copper strip
3.Zinc Strip or Aluminum foil
4.Voltmeter and/or LED (to confirm the passage of electric current)
5.Two beakers
6.Insulated wires

Questions
1.If Ella can't find the copper strip can she use copper wire?

2. Are there any other materials she will need? If so state them.

3. What can she use as a substitute for insulated wire.

4.Write a step to step procedure on how she can construct an electrochemical cell using the given materials listed above.

Answers

Answer:

1. Yes, it will have the same effect.

2. No, she will not need anything else.

3. Bare wires.

4. Fill the two beakers up with electrolyte. Connect the two terminals with the wire and put electricity through. Connect the voltmeter to the circuit. And finally, put the two terminals into the two beakers.

Explanation:

Hope this helped!

What will the core contain

Answers

They fuse helium into carbon. Hope it helped

How would the calculated concentration of the hci be affected if the sodium hydroxide were poured from ma beaker that contained some water before the naoh were added to it

Answers

Answer:

This question is incomplete

Explanation:

This question is incomplete. However, the beaker that contained some water before NaOH were added means that the resulting solution in that beaker will be more dilute. When this diluted sodium hydroxide solution is added to HCl (not hci), the reaction below occurs

HCl + NaOH ⇒ NaCl + H₂O

The reaction above is a neutralization reaction. The concentration of the acid (HCl) will reduce when a base (sodium hydroxide) is added and will also reduce more because of the presence of more water (in the base) which normally reduces the concentration of ions present in an acid or a base to become more dilute.

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