Iodine-131 has a half life of 8.040 days how long will it take for a 40.0 grams sample of iodine 131 to decay to 0.75g

Answers

Answer 1

Answer:

[tex]t=46.13days[/tex]

Explanation:

Hello there!

In this case, since the radioactive decay is considered as first-order kinetic model, whereby the remaining mass of the radioactive material involves the initial one, the rate constant and elapsed time:

[tex]A=Ao*exp(-kt)[/tex]

As we were not initially given the rate constant, we can use the half-life to calculate it as follows:

[tex]k=\frac{ln(2)}{8.040days}=0.08621days^{-1}[/tex]

Thus, we can calculated the elapsed time for the given conditions to obtain:

[tex]t=\frac{ln(0.75g/40.0g)}{-0.08621days^{-1} }\\\\t=46.13days[/tex]

Regards!


Related Questions

How many grams are in 4.00 moles of glucose, C6H120

Answers

Answer:

[tex]molar \: mass = (6 \times 12) + (12 \times 1) + 16 \\ = 100 \: g \\ 1 \: mole \: weighs \: 100 \: g \\ 4.00 \: moles \: will \: weigh \: (4 \times 100) \: g \\ = 400 \: g[/tex]

Consider the following reaction:

4FeS2 + 11O2 → 2Fe2O3 + 8SO2

When 28.42 grams of FeS2 reacts with 5.44 grams of O2, how many grams of SO2 are formed?










What is the limiting reactant?


What is the excess reactant?
I'm begging

Answers

Your limiting reactant is O2 and the excess would be FES2.Do you want me to solve the qn or just ans the qn ;-;

how many moles of gold is 9.75 x 10^24 atoms?

Answers

Answer:

1 Answer. You use the fact that 1 mole of any substance contains exactly 6.022⋅1023 atoms or molecules of that substance - this is known as Avogadro's number. In your case, 1 mole of gold will have exactly 6.022⋅1023 atoms of gold.

Explanation:

Answer:

[tex]\boxed {\boxed {\sf 1.62 \ mol \ Au}}[/tex]

Explanation:

We are asked to convert atoms to moles.

1. Avogadro's Number

We know that 1 mole of any substance contains the same number of particles (atoms, molecules, formula units etc.) This is Avogadro's Number: 6.022*10²³. For this question, the particles are atoms of gold (Au).

2. Convert Atoms to Moles

Let's set up a proportion using this information.

[tex]\frac {6.022*10^{23} \ atoms \ Au}{1 \ mol \ Au}[/tex]

Since we are solving for the moles in 9.75 * 10²⁴ atoms, we multiply by that number.

[tex]9.75*10^{24} \ atoms \ Au*\frac {6.022*10^{23} \ atoms \ Au}{1 \ mol \ Au}[/tex]

Flip the proportion. It will be equivalent, but the units of "atoms Au" can cancel.

[tex]9.75*10^{24} \ atoms \ Au*\frac {1 \ mol \ Au}{6.022*10^{23} \ atoms \ Au}[/tex]

[tex]9.75*10^{24} *\frac {1 \ mol \ Au}{6.022*10^{23}}[/tex]

Condense the problem into 1 fraction.

[tex]\frac {9.75*10^{24} }{6.022*10^{23}}\ mol \ Au[/tex]

[tex]1.619063434 \ mol \ Au[/tex]

3. Round

The original measurement (9.75) has 3 significant figures. Our answer must have the same. For the number we found, that is the hundredth place.

1.619063434

The 9 in the thousandth place tells us to round the 1 to a 2 in the hundredth place.

[tex]1.62 \ mol \ Au[/tex]

9.75 * 10²⁴ atoms of gold is approximately equal to 1.62 moles of gold.

Calculate what the specific heat capacity of an unknown metal is if 394)
of heat were released when 15.0 grams of the substance at 96.0°C was
cooled to 28.0°C?
Formula Reminders
q = mCAT
q = mHvap
q = mHfus
1. 4.01 J/gºC
2. 5910 J/g°C
3. 0.387 J/g°C

Answers

Answer: The specific heat capacity of an unknown metal is [tex]0.387 J/g^{o}C[/tex].

Explanation:

Given: Heat energy = 394 J

Mass = 15 g

Initial temperature = [tex]96^{o}C[/tex]

Final temperature = [tex]28^{o}C[/tex]

Formula used is as follows.

[tex]q = m \times C \times (T_{2} - T_{1})[/tex]

where,

q = heat energy

m = mass of substance

C = specific heat capacity

[tex]T_{1}[/tex] = initial temperature

[tex]T_{2}[/tex] = final temperature

Substitute the values into above formula as follows.

[tex]q = m \times C \times (T_{2} - T_{1})\\394 J = 15 g \times C \times (28 - 96)^{o}C\\C = \frac{394 J}{15 g \times (68^{o}C)}\\= \frac{394 J}{1020 g^{o}C}\\= 0.387 J/g^{o}C[/tex]

Thus, we can conclude that the specific heat capacity of an unknown metal is [tex]0.386 J/g^{o}C[/tex].

What is the molarity of a solution made of 2.45 moles of LiCl in 4.75 L of solution?

Answers

Answer:

.52 M

Explanation:

moles ÷ liters = molarity

2.45 ÷ 4.75 = 0.5157894737

rounding it = .52

What is the chemical name for F5N3

Answers

Answer:

Fluorine azide or triazadienyl fluoride (FN3) is a yellow green gas composed of nitrogen and fluorine with formula FN3. It is counted as an interhalogen compound, as the azide functional group is termed a pseudohalogen. It resembles ClN3, BrN3, and IN3 in this respect.

Explanation:

Answer:

I think it is Fluorine not sure tho

Explanation:

Iron(II) sulfide has a molar mass of 87.91 g/mol. 50 grams of
this substance would contain about 3.011 x 1023 molecules.
TRUE
FALSE

Answers

Answer:

true

Explanation:

Answer:

[tex]\boxed {\boxed {\sf False}}[/tex]

Explanation:

We want to know if 50 grams of iron (II) sulfide contains 3.011 * 10²³ molecules.  Let's calculated and check.

1. Convert Grams to Moles

We know there are 50 grams of iron (II) sulfide or FeS If we want to convert from grams to moles, we use the molar mass (mass per 1 mole). This is given to us and it is 87.91 grams per mole for this substance. Let's create a ratio.

[tex]\frac {87.91 \ g \ FeS}{ 1 \ mol \ FeS}[/tex]

We want to convert 50 grams of FeS to moles, so we multiply by this value.

[tex]50 \ g \ FeS *\frac {87.91 \ g \ FeS}{ 1 \ mol \ FeS}[/tex]

Flip the ratio so the grams of FeS cancel.

[tex]50 \ g \ FeS *\frac {1 \ mol \ FeS}{ 87.91 \ g \ FeS}[/tex]

[tex]50*\frac {1 \ mol \ FeS}{ 87.91}[/tex]

[tex]\frac {50}{ 87.91} \ mol \ FeS[/tex]

[tex]0.5687635081 \ mol \ FeS[/tex]

2. Convert Moles to Molecules

1 mole of any substance contains the same number of particles (atoms, molecules, formula units, etc.). This is Avogadro's Number or 6.022 *10²³. In this case, the particles are molecules of FeS. Create another ratio.

[tex]\frac {6.022 *10^{23} \ molecules \ FeS}{ 1 \ mol \ FeS}[/tex]

We want to convert 0.5687635081 moles of FeS to molecules, so we multiply by this value.

[tex]0.5687635081 \ mol \ FeS*\frac {6.022 *10^{23} \ molecules \ FeS}{ 1 \ mol \ FeS}[/tex]

The units of moles of FeS cancel.

[tex]0.5687635081 *\frac {6.022 *10^{23} \ molecules \ FeS}{ 1 }[/tex]

[tex]0.5687635081 *{6.022 *10^{23} \ molecules \ FeS}[/tex]

[tex]3.42509385*10^{23} \ molecules \ FeS[/tex]

If we round to the thousandth place, the 0 in the tenth thousandth place tells us to leave the 5.

[tex]3.425*10^{23} \ molecules \ FeS[/tex]

50 grams of iron (II) sulfide is approximately 3.425 * 10²³ molecules, not 3.011 *10²³ so the statement is false.

A base is a substance which neutralizes an acid. Which of these substances is not a base?

A. aqueous ammonia
B. sodium chloride
C. sodium carbonate
D. calcium oxide

Answers

Answer: C
im sorry if its wrong but i already took this in school

Among these, sodium chloride is a substance which is not a base, therefore option (b) is correct.

What do you mean by a base in a chemical reaction?

A base is a chemical species that donates electrons, accepts protons, or releases hydroxide (OH-) ions in aqueous solution. A base is a molecule or ion able to accept a hydrogen ion from an acid.

A strong base completely dissociates into its ions in water. Bases react vigorously with acids and organic matter. Bases react in predictable ways with pH indicators.

A base substance is  a solution that has a pH level of more than 7.  Bases react with acids to form salts which is called neutralization reaction.

Among these  since sodium chloride is not a base, hence option(b) is correct.

Learn more about base reaction ,here:

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Neptune _____.

is a terrestrial planet
has a nearly horizontal axis
was discovered by mathematical calculations
is the largest planet in the solar system

Answers

Answer:

C. Was Discovered by Mathematical calculations

Explanation:

Terrestrial Planets are Inner Planets (Mercury,Venus,Earth,Mars) and Neptune is an ice giant or gas giant, Neptune is also not the largest planet in the solar system, I believe that's Jupiter. I don't know for sure if Neptune has a horizontal axis but my best guess is C. I hope this helps! :^)

Suppose you see a crescent Moon. How do you know if it is waxing or waning?

Answers

Answer:

waxing is in the evening and waning is in the morning if you cant see the moon in the evening it is waning if you can see it in the evening it is waxing

A sample of helium has a volume of 3.49 L at 741 mmHg. What would be the volume if the pressure
were changed to 760 mmHg at the same temperature?

show work

Answers

P1: 741 mmHg

V1: 3.49 L P1 x V1 / P2= (741 mmHg) (3.49 L) / 760 mmHg = 3.40 L

P2: 760 mmHg

V2: ? L

The number of molecules in 1.00 liter of O2 gas at 56◦C and 821 torr is
1. 1.83 × 1025 molec.
2. 32 molec.
3. 2.24 × 1023 molec.
4. 2.41 × 1022 molec.
5. 4 × 10−2 molec.

Answers

Answer:

2. 2.41 x 10^22 molec

Explanation:

Answer:

2. 2.41 x 10^22 molec

Explanation:

the other person said that and i got right on my quiz

Humans rely on water for

Answers

Answer:

almost everything

Explanation:

50 POINTS!!!

When writing a chemical reaction equation, what does the arrow ( ---> ) represent?

A. the reactants are making the products
B. the direction of the chemical equation
C. the chemical reaction cannot be reversed
D. all of the above

Answers

The condition or progress of a reaction is represented by reaction arrows. The chemical reaction arrow is a single straight arrow that points from the reactant(s) to the product(s) and by-products, as well as side products.

I think this should help you find the answer more easy!

what is the mass of 4 moles of almunium atom​

Answers

Answer:

108 grams

Explanation:




A leaking underground storage tank or wastewater pouring into a river from a pipe would be examples of

Answers

Answer:

Water pollution.

Explanation:

This is because water pollution refers to the release or disposal of harmful substances called contaminants which contaminate water bodies which include rivers, oceans, lakes e.t.c.. These harmful substances affect aquatic organisms and make water unfit for good use. This can lead to the death if aquatic lives in the water bodies, release of bad smells and make the water bad . A leaking underground storage tank or wastewater pouring into a river from a pipe can be a source of water pollution.

select all that are heterogeneous mixtures.
A) soil
B) steel
C) concrete
D) kool-aid
E) open can of soda

Answers

Soil, concrete, and an open can of soda are all heterogeneous mixtures

Jaclyn's coffee was too hot to drink so she placed the cup in the freezer for 10 minutes. What did Jaclyn know about heat that caused her to take this action?​

Answers

Answer:

Jaclyn knew that Hot temperatures are cooled when out into a colder area.

c) Mercury is solid at room temperature....True Or False

Answers

Answer:

true

Explanation:

Because Mercury can be solidified when its temparature us brought to its freezing point. However, when returned to room temparature conditions, mercury does not exist in solid state for long, and returns back to its more common liquid form.

____Na + ____Cl2 ---> ____NaCl

Answers

Here is the answer of the given question
2 Na + 1 CI2 —> 2 NaCI

which statement is true concerning the Haber Process?

A.
It is a process for the synthesis of nitrogen gas.

B.
It is a process for the synthesis of ammonia.

c.
It is a process for the synthesis of methane.

D.
It is a process for the synthesis of carbon monoxide.

E.
It is a process for the synthesis of carbon dioxide.

Answers

Answer: the answer is B The Haber Process is used in the manufacturing of ammonia from nitrogen and hydrogen, and then goes on to explain the reasons for the conditions used in the process. The process combines nitrogen from the air with hydrogen derived mainly from natural gas (methane) into ammonia.

Explanation: Mark as brainliest if it helped!!

How many moles are there in 8.25 x 10^26 molecules of methane (CH4)?

Answers

Answer:

i dont know

Explanation:

because i dont know 45

Calculate the molar solubility of aluminum hydroxide (AlOH)3) in a 0.027M solution of aluminum nitrate (Al(NO3)3). The Ksp of AlOH)3 is 2.0x10-32.

Answers

Answer:

s = 5.22x10⁻⁹ M

Explanation:

Let's write the equilibrium reaction for this compound:

Al(OH)₃ <-------> Al³⁺ + 3OH⁻      Ksp = 2x10⁻³²

To get the solubility, we need to write the equilibrium expression:

Ksp = [Al³⁺] [OH⁻]³

Al(OH)₃ does not contribute to the equilibrium expression, because is a solid compound. Now, according to this, we have the following:

                   Al(OH)₃ <-------> Al³⁺ + 3OH⁻

I.                                             0          0

E.                                            s          3s

Replacing into the Ksp expression:

2x10⁻³² = (s) (3s)³

2x10⁻³² = s * 27s³

2x10⁻³² = 27s⁴

s = ⁴√2x10⁻³² / 27

s = 5.22x10⁻⁹ M

This would be the solubility of the compound.

Hope this helps

Create a visual model of an ionic substance (salt) dissolving in water and a covalent substance (sugar) dissolving in water.

Answers

Answer:

see image

Explanation:

let me know if you have any questions

why is Cu+O=2CuO unbalanced ​

Answers

Answer:

because the product of CuO contains 2 molecules so it is unbalanced

Explanation:

to balance it 2Cu+2O=4CuO now it is balanced

Because the two before the cuo means there is 2 moles of each atom and in the reactants there is only one mole of each so to balance the equation u need to put 2 before the cu and before the o

Define activation energy.Activation energy is Define activation energy.the energy barrier that must be surmounted in order for the reactants to transform into products.the energy difference between the reactants and the products.the energy released by the reactants while transforming into products.the energy released by the products while transforming into reactant

Answers

Answer:

the energy barrier that must be surmounted in order for the reactants to transform into products.

Explanation:

When we draw a reaction profile, there is always a hump that is found between the reactants and products. This hump is called the activation energy.

The activation energy of a reaction stands as a sort of barrier between reactants and products which must be surmounted before the reactants are converted into products.

Only reactants that possess the activation energy can be converted from reactants to products.

Answer is D

Relatively slow rates of chemical reaction are associated with which characteristic?
A)
High temperature
B)
Low activation energy
C).
The presence of a catalyst
D)
Strong bonds in reactant molecules

Answers

Option D : Strong bonds in reactant molecules

The strong bonds in reactant molecules sometimes needs extra energy to weaken the bond and proceed the reaction. Hence, option D is correct.

What is reaction rate ?

The rate of a reaction is the rate of decrease in concentration of the reactants or decrease in concentration of the reactants or increase in the concentration of the products.

The minimum energy required to overcome the barrier potential of a reaction is called its activation energy. Hence, lower the activation energy higher will be the reaction rate.

High temperature and presence of catalyst also leads to higher rate. Strong bonds in reactants needs higher energy to weaken the intermolecular force. Thus, slower the reaction rate.

Find more on reaction rate:

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PLS HELP ME WILL GIVE BRAIN THINGYYYYY

Answers

Answer:

C, when the ball lands it will have the least amount potential energy.

Explanation:

here is a picture that should help you.

Collisions only result in a reaction if the particles collide with a certain maximum energy called the activation energy of the reaction.

Answers

Answer: The statement collisions only result in a reaction if the particles collide with a certain maximum energy called the activation energy of the reaction, is false.

Explanation:

Activation energy is the minimum amount of energy required to initiate a chemical reaction.

So, when activation energy for a reaction is lower then molecules with lower energy can also participate in the reaction. As a result, more number of collisions will take place due to which an increase in the rate of reaction will takes place.

When activation energy for a reaction is larger then molecules with higher energy will not be able to participate in the reaction. As a result, less number of collisions will take place due to which a decrease in rate of reaction will occur.

Therefore, we can conclude that the statement collisions only result in a reaction if the particles collide with a certain maximum energy called the activation energy of the reaction, is false.

Answer:

true

Explanation:

particularly must collide with energy equal to or greater the

What is considered the human body's largest organ?



Answers

Answer:

The skin

Explanation:

The skin is the largest organ of the body. The skin and its derivatives (hair, nails, sweat and oil glands) make up the integumentary system. One of the main functions of the skin is protection. It protects the body from external factors such as bacteria, chemicals, and temperature.

the skin, the skin run throughout the whole body
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