Nobelium-254 has a half life of 3 seconds. How many half-lives would have to occur to
reduce a 15g sample down to 0.09375g?

Answers

Answer 1

the number of half-lives that would have occur to reduce a 15 g sample of Nobelium-254 down to 0.09375 g is 7.3

To calculate the number of half-lives that would have occur to reduce a 15 g sample of Nobelium-254 down to 0.09375 g, we use the formula below.

Formula:

2ⁿ = R/R'........... Equation 1

Where:

n = Number of half-lives that have occuredR = Original mass of Nobelium-254R' = Mass of Nobelium-254 after decay

From the question,

Given:

R = 15 gR' = 0.09375 g

Substitute these values into equation 1

2ⁿ = 15/0.093752ⁿ = 160n = log160/log2n = 7.3 half-lives

Hence, the number of half-lives that would have occur to reduce a 15 g sample of Nobelium-254 down to 0.09375 g is 7.3

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Related Questions

A student measured and recorded the temperature of the liquid
inside a can of carbonated soft drink. He then poured the soft
drink from the can into a glass filled with ice. Gas bubbles
appeared on the sides of the glass and formed a layer of foam
as they rose to the top of the glass. The mixture gave off a sweet
odor. When the temperature of the soft drink and ice mixture
was measured, the temperature of the mixture was much lower
than the temperature previously recorded for the canned soft
drink. The student concluded a chemical change had taken
place.
Which statement provides the best evidence that the student's
conclusion is wrong?
Gas bubbles
appeared on the
sides of the glass.
No new substances
were formed.
There was a change
in temperature.
The mixture gave off
a sweet odor.

Answers

There is the change in temperature is the correct answer.

What is a carbonated soft drink?

Carbonated beverages are drinks that include carbon dioxide dissolved in water.

It is given as the formation of bubbles and the odour will be concluding with the formation of the new product and thereby a chemical change. Whereas there was no chemical change if the temperature lowers down as the reason stands to be the formation of a mixture.

Hence, there is a change in temperature.

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What is the importance of antacid in the body​?​

Answers

Antacids are medicines that counteract (neutralise) the acid in your stomach to relieve indigestion and heartburn. They come as a liquid or chewable tablets and can be bought from pharmacies and shops without a prescription.

Answer:

The substances which neutralize the acids of the stomach are called antacids. Acidity in the stomach causes the sensation of heartburn, antacids are taken to relieve this sensation. They are taken orally to suppress the effects of acidity.


How many spaces away from a Noble gas are the following elements?
a. Na, Li, K and Cs?

Answers

Answer:

Na - 1 away from neon

Li - 1 away from helium

K - 1 away from argon

Cs - 1 away from xenon

Explanation:

We see this trend as group 1A elements are 1 away from noble gases and hence, have a valency of 1

What percentage of the atmosphere is carbon dioxide?.

Answers

Answer:

4%

Explanation:

the answer is 4% , hope this help

What is one thing that could have prevented the Chernobyl tragedy?

Answers

Answer: if the staff at Chernobyl had been better trained.

The Chernobyl series seems to suggest there were a number of ways the explosion could have been prevented. These include if the staff at Chernobyl had been better trained, if the Soviet government had learned from the lessons of the past and if they had not been so averse to spending money.

A mother and two young children are found passed out in their apartment, where a space heater is on. Emergency medical technicians suspect carbon monoxide poisoning. Why is carbon monoxide dangerous

Answers

Answer:

ummm a I guess if I am wrong tell me

1.50 atmospheres to kPa

Answers

Answer:

151.988 how i don't know

What mass of Ca(OH)2 is contained in 1500 mL of 0.0250 M Ca(OH)2 solution?


Your answer:


1.85 g



2.34 g



2.78 g



3.17 g

Answers

We need moles of Ca(OH)_2

Molarity=Moles/Volume in L0.025=Moles/1.5Moles=1.5(0.025)Moles=0.0375mol

Molar mass of Ca(OH)_2=74g/mol

Now

Mass=Molar mass×MolesMass=0.0375×74Mass=2.77g

Option C

The mass of Ca(OH)₂ in the given solution is approximately 2.78 grams, which corresponds to option C) 2.78 g.

Given: Volume = 1500 mL, Concentration (Molarity) = 0.0250 M, and Compound = Ca(OH)₂ .

First, convert mL to L: Volume = 1500 mL × (1 L / 1000 mL) = 1.5 L.

Use the formula for calculating the number of moles: Moles = Concentration × Volume.

Moles = 0.0250 mol/L × 1.5 L = 0.0375 mol.

The molar mass of Ca(OH)₂  can be calculated:

Ca(OH)₂  molar mass = (1 * atomic mass of Ca) + (2 * atomic mass of O) + (2 * atomic mass of H)

= (1 * 40.08 g/mol) + (2 * 16.00 g/mol) + (2 * 1.01 g/mol)

= 74.09 g/mol.

Now, calculate the mass using the calculated moles and molar mass:

Mass = Moles × Molar mass

Mass = 0.0375 mol × 74.09 g/mol = 2.78 g.

Therefore, the mass of Ca(OH)₂  in the given solution is approximately 2.78 grams, which corresponds to option C) 2.78 g.

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The complete question is:

What mass of Ca(OH)₂ is contained in 1500 mL of 0.0250 M Ca(OH)₂ solution?

A) 1.85 g

B) 2.34 g

C) 2.78 g

D) 3.17 g

How many moles are there of a 2 M solution with a volume of 17.95 liters?

Answers

Answer:How many moles are there of a 2 M solution with a volume of 17.95 liters = 35.9 moles !

Explanation: The formula for calculating the molarity of the solution is expressed as Molarity= mole/volume

Molarity = 2 M

Volume=17.95L

Substitute the given parameters into the formula … and you get

mole=molarity x volume

Mole=2M x 17.95L

Mole=35.9moles

moles of the solution is 35.9 moles

Hope this helps if so mark Brainalist thanks

A solution has [H3O+] = 2.8x10-5 M. Use the ion product constant of water K. = [H30 - ) [OH-] to find the [OH-] of the solution. Express your answer to two significant figures.​

Answers

Answer:

Approximately [tex]3.6 \times 10^{-10}\; {\rm M}[/tex], assuming that the solution is dilute and is at room temperature (such that [tex]K_\text{w} = 10^{-14}[/tex].)

Explanation:

Look up the ion product constant of water:

[tex]K_{\text{w}} \approx 10^{-14}[/tex].

In a dilute solution where water is the solvent, the product of [tex][{\rm {H_{3}O}^{+}}][/tex] and [tex][{\rm {OH}^{-}}][/tex] (concentration of [tex]\rm {H_{3}O}^{+}}[/tex] ions and [tex]{\rm {OH}^{-}}[/tex] ions) is constantly equal to [tex]K_{\text{w}}[/tex]. (The unit of both [tex][{\rm {H_{3}O}^{+}}]\![/tex] and [tex][{\rm {OH}^{-}}]\![/tex] need to be [tex]{\rm M}[/tex].) In other words:

[tex][{\rm {H_{3}O}^{+}}]\, [{\rm {OH}^{-}}] = K_{\text{w}}[/tex].

Rearrange this equation to find [tex][{\rm {OH}^{-}}][/tex] in terms of [tex]K_{\text{w}}[/tex] and [tex][{\rm {H_{3}O}^{+}}][/tex]:

[tex]\begin{aligned}[] [ {\rm OH^{-}} ] &= \frac{K_{\text{w}}}{[{\rm {H_{3}O}^{+}}]} \\ &= \frac{10^{-14}}{2.8 \times 10^{-5}} \\ &\approx 3.6 \times 10^{-10}\end{aligned}[/tex].

How hot or cold the air is.

Answers

It’s cold and humid because of the temp rising it affects it yk.

hydration and solvation which the solvent is water. what is solvation?

Answers

Answer:

Solvation is the interaction of a solvent with the dissolved solute—in the case of water, solvation is often referred to as hydration. Solvent polarity is the most important factor in determining how well it solvates a particular solute.

Explanation:

hope this helps :)

How are acids described according to the bronsted-lowry definition?.

Answers

Answer:

an acid is a proton (H⁺) donor

Explanation:

hope this helps

pls nmark brainliest

Why is it possible for an oxygen atom to form a double covalent bond, but its not possible for a chlorine atom to form a double covalent bond?

Answers

In a double covalent bond, it is when 2 atoms share 2 pairs of electrons. Chlorine can't form a double because it only has one free valence electron which means it can't make two pairs, one one while the oxygen can. Compare and contrast Covalent, Ionic, and Metallic bonds.

Ocean salinity will vary with evaporation as well as with freezing and thawing. True or False?
True
False​

Answers

Answer: true

Explanation:

Ocean salinity will vary with evaporation as well as with freezing and thawing. this statement is true.

What is Ocean salinity?

Salinity, commonly known as saline water (also see soil salinity), is the degree of saltiness or the quantity of salt dispersed throughout a body of water. The standard units of measurement are grammes of salt per litre (g/L) or grammes per kilogramme (g/kg; the latter one is dimensionless therefore equal to ).

Salinity is a thermodynamic condition variable that, along with pressure and temperature, controls physical properties like the density also heat capacity of the water. Salinity plays a significant role in defining numerous facets of the chemical composition of natural waters as well as the biological processes within them. Ocean salinity will vary with evaporation as well as with freezing and thawing. this statement is true.

Therefore, ocean salinity will vary with evaporation as well as with freezing and thawing. this statement is true.

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The mass spectrum of an organic compound shows the relative abundances of M to be 34.76% and M 1 to be 2.632%. Assuming the peaks are caused by C12 and C13 isotopes, determine the number of carbon atoms in the compound. The natural abundance of C12 is 98.93%, and the natural abundance of C13 is 1.07%.

Answers

The number of carbon atoms present in any compound is equal to seven.

How do we calculate the number of carbon atoms?

Number of carbon atoms present in any compound will be calculated by using the following equation:

No. of Carbon atoms = Relative intensity of M+1 peak / Natural abundance of C13

Intensity of molecular peak = 34.76%

Intensity of M+1 peak = 2.632%

Relative intensity of M+1 peak = (100/34.76)×2.632 = 7.57%

Given that natural abundance of M+1 = 1.07%

On putting values on above equation, we get

No. of C atoms = 7.57 / 1.07 = 7.07 = 7 (approx)

Hence number of carbon atoms is 7.

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Which gas law relates pressure and volume?

- Is there a direct or indirect relationship?
- What variable is held constant?

Answers

Gas laws are the relation between pressure, volume, and temperature of the gas. The relation between the pressure and the volume of the gas is given by Boyle's law.

What is Boyle's law?

Boyle's law gives the relation between the pressure and the volume of the gas and states that the pressure is in the inverse relationship with the volume of the gas.

When the pressure of the gas is increased the volume of the gas decreases, similarly the decreased pressure of gas results in an increased volume of gas.

Boyle's law is given as,

[tex]\rm V = \rm constant (\dfrac{1}{P})[/tex]

and,

[tex]\rm P_{1}V_{1} = \rm P_{2}V_{2}[/tex]

Boyle's law is only true if the moles of the gas (n) and the temperature (T) of the gaseous system are constant.

Therefore, pressure and volume are in indirect relation and the moles and the temperature are constant in Boyle's law.

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What is the power of a food processor that can perform 1,350 joules of work in 15 seconds

Answers

Power is energy divided by time and it’s unit is watta(W)

A sample of carbon monoxide and oxygen gasses are
allowed to combust in a small flask. They reaction is
described by the following equation.
2CO (g) + O₂ (g) → 2CO2 (g)
After the reaction is complete, the pressure of CO₂ is 0.868
atm and the temperature is 35.0 °C in a 500.0 mL flask. How
many moles of CO2 were produced assuming that the
reaction went to completion?

Answers

Answer:

.0172 mole of CO2

Explanation:

PV = nR T      n = number of moles      V = .5 liter

                       R = gas constant = .082057 L atm/(k mole)

                           T needs to be in Kelvin =  C + 273.15

.868  * .5  = n * .082057 * ( 35 + 273.15)

 n = .0172 moles


A sample of nitrogen gas reacts with an excess of hydrogen gas to give an actual yield of 20.05 g NH3. The theoretical yield is 26.46g.
What is the percent yield for this reaction?
Round to two decimal places
N2(g) + 3H2(g)+2 NH3 (g)

Answers

Answer: 75.77%

Explanation:

Percent yield = (actual yield)/(theoretical yield) = 20.05 / 26.46 * 100 = 75.77%

What is the concentration of an aqueous solution with a volume of

550 mL that contains 350 grams of iron (II) chloride (FeCl2)?

Answers

Answer:

Explanation:

The formula for concentration is C = n/V

Where C represents concentration in mol/L.

n represents moles in mol.

V respresents volume in L.

You have 550 mL, let's convert it to L (1000 mL= 1L)

550 mL / 1000 = 0.55 L

We got V and we need n. We can find n by this formula:

n = m/M

m represents mass in g.

M represents molar mass in g/mol.

We are given grams of iron (II) chloride (FeCl2)

Find the molar mass by the periodic table: 55.85 + (2*35.45) = 126.75 g/mol.

n = (350 g) / (126.75 g/mol) = 2.76134 mol

Back to our first formula: C = n / V

C = (2.76134 mol) / (0.55 L) = 5.0206 mol/L.

to 3 significant digits it's 5.02 mol/L, and that is how you find concentration.

18. 0mols of sodium reacts with excess chlorine. How many

grams of sodium chloride form?

please help

Answers

Answer:

I think the answer is 0 because 0 mols of sodium react

Explanation:

Which enzyme of the citric acid cycle most closely resembles the pyruvate dehydrogenase complex in terms of its structure, organization, and the reaction it performs

Answers

Answer:

The α-ketoglutarate dehydrogenase enzyme is structurally and functionally homologous to the pyruvate dehydrogenase complex.

hope it helps

Can someone please help me? :(

Answers

nuclear energy, once used up it can not be used again

please help smart kids HHowhotwill a 2.3 L balloon have to get to expand to a volume of 400 L? Assume that the initial temperature of the balloon is 25 degrees C.

Answers

Answer:

51 579 C

Explanation:

I will assume the PRESSURE remains constant

then

V1 /T1  = V2/T2       T will be in Kelvin

                                25 C =  298.15 K

2.3 l / 298.15 K    =  400 l / T2

solve for T2 = 51852.17 K   = 51579 C

[tex]\huge\mathfrak\colorbox{white}{}[/tex]

According to LOCO mass, the mass of reactants and products are what?

Answers

Answer:

Equal

Explanation:

According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.

A balloon contains 7. 2 L of helium. The pressure is reduced to 2. 00 atm and the balloon expands to occupy a volume of 25. 1 L. What was the initial pressure exerted on the balloon?

Answers

Answer:

your answer should be 0.57 atm

Which factor does not affect the rate of solubility?.

Answers

Answer:
Anything that isn’t surface area, mixing or stirring, and (usually increased) temperature.

Explanation:
An increase in surface area means more collision and overall rate in dissolving.
Mixing or stirring also increases and even forces collisions.
Temperature causes the molecules to move faster, increasing the amount of collisions.

PLEASE HELP MEE !!!!!

1. Which organism is the main source of energy for the food web (producer)?
2. Which is a food chain you can get from this food web?
3. Which organism is a primary consumer?
4. Which organism would be considered a secondary consumer?
5. Which organism is a top predator?
6. Which organism is a decomposer?
7. Can energy recycle back into the food web?


PLEASE AND THANKYOU <33

Answers

Answer:

Hope it helps

Explanation:

1. Phytoplankton is the main source of energy.

2. Algae--> Limpet--> Starfish --> Shark (I am not sure about this answer )

3. Limpets (not sure, sorry) I think there are more than one in this, like Mussel, zooplankton...

4.  Starfish

5. Shark

6. Bacteria

7. No, energy cant be recycled back into the food web.

I tried my best to answer. Hope it will help you.

Copper(II) sulfate is an example of a substance that dissolves in water. Copper(II) sulfate is an ionic compound with the chemical formula CuSO4 and when it is added to water it dissociates into Cu2+ and SO42− ions. Students used both copper sulfate crystals and copper sulfate powder in this experiment on the rate of dissolving. Choose one statement that represents a valid conclusion based on the student data?


A) The smaller the solute particles the more energy they have. Increased energy results in shorted dissolving time.


B) A given quantity of solute dissolves faster when it is ground into small particles because more surface area is exposed.


C) As the water temperature increased, the copper sulfate crystals dissolved faster but there was little change for the powdered form.


D) Agitation of the powder allows fresh solvent molecules to continually be in contact with the solute

Answers

As the water temperature increased, the copper sulfate crystals dissolved faster but there was little change for the powdered form.

Does increase in temperature make solids to dissolve faster?

Increasing the temperature of a solvent can increase the rate at which a solid dissolves. This is because an increase in temperature causes the solvent molecules to move more rapidly, which in turn increases their kinetic energy and ability to interact with the solute particles.

As a result, the solute particles are more likely to break free from their crystal lattice and become surrounded by the solvent molecules.

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Answer:

A given quantity of solute dissolves faster when it is ground into small particles because more surface area is exposed.

Explanation:

The more surface area of a solute that is exposed, the faster the solute will dissolve. Like sugar for an example, sugar cubes take longer to dissolve as compared to regular ground up sugar.

And I took the test and got this right!

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