How much time would it take for 40000 atoms of sodium-24 (half-life is 15 days) to decay to 2500 atoms?

Answers

Answer 1

Answer:

60 days

Explanation:

2500 = 40000 ( 1/2) ^n

n = 4 half lives

4 half lives * 15 days/ halflife = 60 days


Related Questions

PLEASEEEEE HELP
1 Explain why decan-1-ol CH,(CH,) CH,OH has

only limited solubility in water, whereas ethanol

CH,CH,OH is miscible with water in all proportions.

2 Give details of the reagents and the practical

procedures required to prepare each of the following

substances from a named alcohol:

a 1-Chloropropane

b 2-Bromopropane.

3 Explain why sodium metal reacts more slowly with

ethanol CH,CH,OH than with water HOH.

4 Draw Lewis structures to show the formation of the

ethoxide ion by the action of sodium on ethanol.

Answers

Answer:

Can you arrange it? I don't understand


Which of the following distinguishing electron configurations is characteristi
of noble gases?
O nf14
Ond10
O npo
Ons2

Answers

Answer:

no.3 is your correct answer

Listed below are the step equations for the reaction in which sulfur dioxide (SO2) and hydrogen disulfide (H2S) react to produce sulfur and water. Write the balanced target equation and use Hess’s law to calculate the ΔH of this reaction.

SO2 (g) → S (s) + O2 (g) ΔH = +300.1 kJ
H2 (g) + S (s) → H2S (g) ΔH = –19.5 kJ
H2 (g) + O2 (g) → H2O (g) ΔH = –290.1 kJ

Answers

Based on Hess law, the enthalpy change, ΔH of the reaction is +48.9 kJ.

What is the equation of the reaction?

The equation of the reaction of sulfur dioxide (SO2) and hydrogen disulfide (H2S) to produce sulfur and water is given below:

[tex]SO_2 + 2H_2S \rightarrow 3S + 2H_2O[/tex]

The ΔH of the reaction is calculated from the summation of the ΔH of the intermediate reactions according to Hess law.

SO2 (g) → S (s) + O2 (g) ΔH1 = +300.1 kJ

H2 (g) + S (s) → H2S (g) ΔH2 = –19.5 kJ

2H2 (g) + O2 (g) → 2H2O (g) ΔH3 = –290.1 kJ

ΔH of the reaction = ΔH1 + 2(-ΔH2) + ΔH3

ΔH of the reaction = 300 + 2 × -(-19.5) + (-290.1)

ΔH of the reaction = +48.9 kJ

Therefore, the ΔH of the reaction is +48.9 kJ.

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what would be the mass of 4.640 x 10^21 particles of aluminum

Answers

One mole of aluminum  contains 6.02 × 10²³ Al  particles. One mole of Al weighs 27 g. Hence 4.60 × 10²¹ Al particles or 0.007 moles weighs 0.208 g.  

What is one mole ?

One mole of a substance is its amount containing 6.02 × 10²³  atoms or molecules. This number is called Avogadro number. One mole of every elements contains Avogadro number of atoms.

Similarly one mole of every compound contains 6.02 × 10²³ molecules. The mass of one mole of compound is called its molar mass. Similarly mass of one mole of an element is called its atomic mass.

Al is 13th element in periodic table. Al is a metal.  One mole of Al contains 6.02 × 10²³ Al  atoms . Hence number of moles of   4.60 × 10²¹ Al particles is:

4.60 × 10²¹/ 6.02 × 10²³  = 0.0077 .

atomic mass of Al = 27 g/mol.

Then mass of 0.0077 moles =  0.0077 × 27 = 0.208 g

Therefore, the mass of  4.60 × 10²¹ Al particles is 0.208 g.

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When a thermometer is suspended in an insulated thermos that contain a block of ice, the temperature recorded on the thermometer drops. Describe the direction of heat flow.​

Answers

The heat flows from inside to the outside direction because of lowering of temperature inside the thermos.

How the temperature of ice drops?

When a thermometer is suspended in an insulated thermos that contain a block of ice, the temperature recorded on the thermometer drops, the direction of heat flow is from inside to the outside the thermos. This is because of the insulating material in which the ice is kept and the lowering of the temperature.

So we can conclude that the heat flows from inside to the outside direction because of lowering of temperature inside the thermos.

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A laboratory group measures an excess of a volatile liquid. They add this to an empty flask with a volume of 66 mL. They heat the sample to 86.9 degrees Celcius until all the liquid is vaporized. The pressure in the lab is 0.987 atm. If 0.287 grams of volatile liquid were left in the flask, what was the molar mass of the compound?

Answers

Answer:

130.159

Explanation:

P=0.987

V=66ml =66/1000=0.066 L

n/moles= ?

R=0.08206

T=86.9+273.15=360.5 K

Formula PV=RnT

n =PV/TR

n=(0.987 * 0.066)/(360.05 * 0.08206) = 0.002205

Now to obtain molar mass  you divide grams by mol.

0.287/0.002205 = 130.159

according to newtons second law of motion,what is force equal to?

Answers

Answer:

This isn't chemistry but the answer is Force = mass x acceleration

copper ii oxide and charcoal are black solids how would you distinguish between the two solid​

Answers

Answer:Charcoal will burn. You may also be able to distinguish it by smell, since it's rarely purged of all its “burnt wood” residue. Copper oxide will dissolve in a strong acid, such as hydrochloric or sulphuric and form a blue solution

Explanation:

Florida and the eastern border of South Carolina share a regional landform characterized by flat land and low elevation. Identify the landform shared by both states.

Karst
Keys
Coastline
Plateau

Answers

Answer: it is coastline.

Explanation: This anwser would only makw sense because of the low elevation and the flat land.

The landform shared by Florida and the eastern border of South Carolina is the coastline. Option C is the correct answer.

Both states are located along the Atlantic Ocean and have a similar geographical feature characterized by flat land and low elevation along their eastern borders. Option C is the correct answer.

The coastline refers to the area where the land meets the sea. It is typically marked by sandy beaches, coastal marshes, and barrier islands. In the case of Florida and the eastern border of South Carolina, this coastline is known for its relatively flat terrain and low elevation, which makes it susceptible to flooding and storm surge during hurricanes. The coastline plays a significant role in the economies and ecosystems of both states. It attracts tourism and provides opportunities for recreational activities such as beachgoing, fishing, and boating. It is also a vital habitat for various marine and coastal species, including birds, turtles, and marine mammals.

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The complete question is, "Florida and the eastern border of South Carolina share a regional landform characterized by flat land and low elevation. Identify the landform shared by both states.

a. Karst

b. Keys

c. Coastline

d. Plateau"

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G Cotton gin - Wikipe... Copy of SOL 2 and..
2 pts
IN
Question 1
Determine Pxe in a container that has the following gases and respective pressures:
Gas
Pressure (kPa)
Xenon
?
Helium
77.3
Nitrogen dioxide
52.0
TOTAL
248.8

Answers

From the total pressure of the gaseous mixture, the partial pressure of xenon is 119.5 kPa

What is partial pressure of a gas?

The partial pressure of a gas is the pressure that gas exerts when it is part of a mixture of gases which did not chemically react together.

The sum of the partial pressure of each gas in the mixture gives the total pressure.

In the gaseous mixtures above:

Total pressure = 248.8 kPa

Partial pressure of xenon = Total pressure - (Sum of partial pressure of the other gases)

Partial pressure of xenon = 248.8 - (77.3 + 52.0)

Partial pressure of xenon = 119.5

Therefore, the partial pressure of xenon is 119.5 kPa.

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pls pls help me with this

Answers

Answer:

1. lava

2. caldera

3. true

4. true

5. before

A solution contains an unknown amount of dissolved magnesium. Addition of
0.0877 mol of Na2CO3 causes complete precipitation of all of the magnesium.
What mass of magnesium was dissolved in the solution?

Answers

Taking into account the reaction stoichiometry, 2.13 grams of magnesium was dissolved in the solution.

Reaction stoichiometry

In first place, the balanced reaction is:

Mg²⁺(aq) + Na₂CO₃(aq) → MgCO₃(s) + 2 Na⁺(aq)

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Mg²⁺: 1 mole Na₂CO₃: 1  moleMgCO₃: 1 moleNa⁺: 2 moles

The molar mass of the compounds is:

Mg²⁺: 24.3 g/moleNa₂CO₃: 106 g/moleMgCO₃: 84.3 g/moleNa⁺: 23 g/mole

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

Mg²⁺: 1 mole ×24.3 g/mole= 24.3 gramsNa₂CO₃: 1 mole ×106 g/mole= 106 gramsMgCO₃: 1 mole ×84.3 g/mole=84.3 gramsNa⁺: 2 moles ×23 g/mole= 46 grams

Mass of magnesium dissolved

The following rule of three can be applied: If by reaction stoichiometry 1 mole of Na₂CO₃ react with 24.3 grams of magnesium, 0.0877 moles of Na₂CO₃ react with how much mass of magnesium?

[tex]mass of magnesium=\frac{0.0877 moles of Na_{2}C O_{3}x24.3 grams of magnesium }{1 mole of Na_{2}C O_{3}}[/tex]

mass of magnesium= 2.13 grams

Finally, 2.13 grams of magnesium was dissolved in the solution.

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What is bee venom an example of?
O nucleic acid
O carbohydrate
O fat
O protein

Answers

Answer:

O protein

Explanation:

Bee venom (BV) is a complex mixture of proteins and contains proteins such as phospholipase and melittin, which have an effect on blood clotting and blood clots.

HGD

A 0.250 mol sample of gas at 35.0°C exerts a pressure of 700 torr in it's container. What pressure will the container exert if the volume expands to 10.0L and the temperature is cooled to 5.0°C?

Answers

29 temperature because if the temperature is more then the 5.of

Where would the points for 1-pentene be
expected to fall?

Answers

To the left of black points

Calculate the molarity of a solution prepared by diluting 7.0 mL of 4.0 M solution to a volume of 30 mL. Select the correct answer below: 0.76 M 0.87 M 0.93 M 1.02 M

Answers

Answer:

0.93 M

Explanation:

Molarity = [tex]\frac{Moles}{Volume}[/tex]

4.0M = [tex]\frac{x}{0.007 L}[/tex]

4.0 M x 0.007 L = Moles = 0.028

Molarity = [tex]\frac{Moles}{Volume}[/tex]

Molarity = [tex]\frac{0.028 moles}{0.03 L}[/tex]

= 0.93 M

Silver chromate is sparingly soluble in aqueous solutions. The sp of Ag2CrO4 is 1.12×10−12.
What is the solubility (in mol/L) of silver chromate in 1.20 M potassium chromate aqueous solution?
What is the solubility (in mol/L) of silver chromate in 1.20 M silver nitrate aqueous solution?
What is the solubility (in mol/L) of silver chromate in pure water?

Answers

The solubility (in mol/L) of silver chromate in 1.20 M in potassium chromate,  silver nitrate and in pure water is

X = 5.0*10^-7 MX'' = 8.333*10^-13 MX'''= 6.694*10^-5 M

This is further explained below

What is the solubility (in mol/L) of silver chromate in 1.20 M potassium chromate aqueous solution?

Generally,The Chemical reaction is

Ag2CrO4 <----> 2 Ag+ + CrO42-

Ksp = [Ag+]^2[CrO42-]

1.12×10−12 = [Ag+]^2[CrO42-]

Hence

1.12×10−12.=(2X)^2*(1.2)

X = 5.0*10^-7 M

b)

1.12×10−12=(1.2)^2*(X)

1.12×10−12= 1.44 * 1(X)^1

X'' = 8.333*10^-13 M

In conclusion

1.12×10−12=(2X)^2*(s)

1.12×10−12= 4(X)^3

X'''= 6.694*10^-5 M

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what is mass ? give two examples ​

Answers

mass it the  amount of matter present in any object or body. Everything we see around us has mass. For example, a table, a chair, your bed, a football, a glass, and even air has mass.

if you were to engineer an everyday solution for conserving water which activity do you think would be the most impactful ?

Answers

if you were to engineer an everyday solution for conserving water which activity do you think would be the most impactful ?

Which adaptation do polar bears and camels have in common?
A. Thick layer of body fat for food storage and insulation.
B. A small surface area to volume to reduce heat loss.
C. Thin fur and little body fat.
D. Large feet to spread body weight.

Answers

Answer:

Thick layer of body fat for food storage and insulation

Explanation:

Polar bears store food for themselves and so do camels. Option B is not correct because bears do not definitely have small surface area and even if camels do they do not need to reduce heat loss because they stay in the deserts. For option C polar bears have thick fur and much body fat to protect itself from the cold. Lastly D cannot be true because camels don't normally have large feet they have small padded foot.

Calculate the Kelvin and Fahrenheit temperature equivalent to 37° Celsius.

Answers

Answer:

310.15 Kelvin. 98.6 Farenheit

Explanation:

To calcuate the celsius to Kelvin you add 273.15 to the celsius. To calculate the celsius to farenheit you do (°C × 9/5) + 32 = °F. For the example, (37°C × 9/5) + 32 = 98.6°F.

Which of the following best describes the process of carbon dioxide
sequestration?
O A. Technologies reduce the amount of carbon dioxide consumed by
forests.
O B. Technologies capture carbon dioxide and inject it into rock
formations,
O C. Technologies reduce the amount of carbon dioxide produced by
factories.
O D. Technologies capture carbon dioxide and release it into the
atmosphere

Answers

Answer:

C. Technologies reduce the amount of carbon dioxide produced by

factories.

Explanation:

simply the answer is C. trust me, im very smart

what is the size of an atom when it generally decreases

Answers

Answer:

the size depends on where is moves across the periodic table.

You are conducting an experiment with two very reactive substances. One will react with oxygen (O) and other substances in the air, and the other will react to metal in a container. What type of environment can you seal them in so they only react with each other?

A. Seal them in a glass container in an atmosphere of argon (Ar) gas.
B. Suspend them in a bromine (Br) solution inside a glass container.
C. Seal them in a container of soft alkali metal such as lithium (Li), in an atmosphere of hydrogen (H) gas.
D. Seal them in a container made of alkali earth metal, such as calcium (Ca).

Answers

Answer:

A. Seal them in a glass container in an atmosphere of argon (Ar) gas.

Because Argon is an inert/noble gas which do not react with other elements/radicals. Thus, best way to make two radicals/substance only react is to seal them in glass container consisting atmosphere of Argon (Ar)..

Note: I also dont know if it's correct answer.. Since I am just giving my logic.. I hope it will help you

- Regards Rishab...

Answer: C. Seal them in a glass container in an atmosphere of argon (Ar) gas.

Explanation: Founders Educere answer ;)

This adaptation allows the panda to perform which activity?



A
Grasping
B
Running
C
Scratching
D
Throwing

Answers

Answer:

A grasping :)

Explanation:

The panda uses the "thumb" to grab onto bamboo to eat! Without this, the panda would not be able to eat the bamboo!

Have an amazing day!!

Please rate and mark brainliest!!

Do the reactants or the product have greater potential energy

Answers

Answer:

the reactants have more potential energy than the products have. The extra energy is released to the surroundings.

Covalent bonding involves the sharing of electrons to create a full valence shell, and
occurs between nonmetals.
True
False

Answers

True. Covalent bonds involve sharing electrons to create a full valence shell.
The answer is: true
<3

4.55 Classify the following redox reactions. (a) 2H2O2 ⟶ 2H2O + O2 (b) Mg + 2AgNO3 ⟶ Mg(NO3)2 + 2Ag (c) NH4NO2 ⟶ N2 + 2H2O (d) H2 + Br2 ⟶ 2HBr

Answers

A- Decomposition .
B- Single replacement.
C-Decomposition.
D-Synthesis.

The following redox reactions are classify as:

(a) 2H₂O₂ ⟶ 2H₂O + O₂: Disproportionation reaction (redox)

(b) Mg + 2AgNO₃ ⟶ Mg(NO₃)₂ + 2Ag: Single displacement reaction (redox)

(c) NH₄NO₂ ⟶ N₂ + 2H₂O: Decomposition reaction (redox)

(d) H₂ + Br₂ ⟶ 2HBr: Combination reaction (redox)

(a) 2H₂O₂ ⟶ 2H₂O + O₂

This reaction involves hydrogen peroxide (H₂O₂) breaking down into water (H₂O) and oxygen gas (O₂). The oxidation state of oxygen in hydrogen peroxide is -1, and in water, it is -2. Oxygen in oxygen gas has an oxidation state of 0. Therefore, oxygen is being reduced from -1 to 0. The oxidation state of hydrogen remains +1 in H₂O₂ and H₂O. Since one element (oxygen) is reduced and the other (hydrogen) remains unchanged, this is a disproportionation reaction (a type of redox reaction).

(b) Mg + 2AgNO₃ ⟶ Mg(NO₃)₂ + 2Ag

In this reaction, magnesium (Mg) reacts with silver nitrate (AgNO₃) to form magnesium nitrate (Mg(NO₃)₂) and silver (Ag). The oxidation state of magnesium changes from 0 to +2 in Mg(NO₃)₂, while the oxidation state of silver changes from +1 in AgNO₃ to 0 in Ag. This is a single displacement reaction (a type of redox reaction) because one element (magnesium) displaces another (silver) in the compound.

(c) NH₄NO₂ ⟶ N₂ + 2H₂O

This reaction involves ammonium nitrite (NH₄NO₂) decomposing into nitrogen gas (N₂) and water (H₂O). The oxidation state of nitrogen in NH₄NO₂ is +3, and in nitrogen gas (N₂), it is 0. The oxidation state of hydrogen changes from +1 in NH₄NO₂ to +1 in H₂O. Since nitrogen is being reduced from +3 to 0, and hydrogen remains unchanged, this is a decomposition redox reaction.

(d) H₂ + Br₂ ⟶ 2HBr

In this reaction, hydrogen gas (H₂) reacts with bromine gas (Br₂) to form hydrogen bromide (HBr). The oxidation state of hydrogen changes from 0 in H₂ to +1 in HBr, while the oxidation state of bromine changes from 0 in Br₂ to -1 in HBr. This is a combination reaction (a type of redox reaction) because two elements (hydrogen and bromine) combine to form a compound (hydrogen bromide), and their oxidation states change during the reaction.

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Elements in which family would require the least amount of ionization energy (the
amount of energy used to take away an electron)?

transition metals
Alkali metals
Alkaline earth metals

Answers

Alkali metals require least amount of ionization energy.

Peaky Blinder fan? haha

name this please, please pleas

Answers

Answer:

propyne

Explanation:

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