Zn-71 has a half life of 2.4 minutes. If one had 100g at the beginning, how many grams would be left after 12 minutes?

Answers

Answer 1

3.125g

Explanation

2.4 minutes = 1 half life

so 12 minutes = 5 half lives (12/2.4)

100g/2 = 50g (1 half life)

50g/2 = 25g (2 half lives)

25g/2 = 12.5g (3 half lives)

12.5g/2 = 6.25g (4 half lives)

6.25g/2 = 3.125g (5 half lives)


Related Questions

A sample of ethanol (C2H6O) has a mass of 0. 2301 g. Complete combustion of this sample causes the temperature of a bomb calorimeter to increase by 1. 33°C. The calorimeter has a mass of 2. 000 kg and a specific heat of 2. 45 J/g•°C. What is the heat of combustion for this sample? kJ.

Answers

The heat of combustion of the sample is calculated to be  -1300 kJmol-1.

We know that energy is neither created nor destroyed but is converted from one form to another. The heat lost by the ethanol when it is burnt is equal to the heat gained by the calorimeter.

Heat gained by calorimeter =  2.×10^3 g ×  2. 45 Jg-1°C-1 × 1. 33°C

= 6.5 kJ

Number of moles of ethanol =  0. 2301 g/46 g/mol = 0.005 moles

Heat of combustion of the sample = -( 6.5/0.005 moles) = -1300 kJmol-1

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What is leukemia?
A. Cancer that affects the blood
B. Prostate cancer
C. Breast cancer
D. Lung cancer

Answers

Answer:

A: Cancer that affects the blood

information: Leukemia is a cancer of the early blood-forming cells. Most often, leukemia is a cancer of the white blood cells, but some leukemias start in other blood cell types.

What are some advantages to the use of hydrokinetic energy? What might be some disadvantages?.

Answers

Hydro-kinetic energy has advantages of being a clean, domestic, and renewable source with effective production. The disadvantages have been affected marine environment, along with water quality, and electricity on drought.

Hydro kinetic energy has been the energy produced by the movement of water bodies in the form of tides, waves, and oceanic current. The hydro-kinetic energy has been composed with high energy entrapped in the water bodies.

Some of the advantages of hydro-kinetic energy has been:

It has been a clean energy source and has been  pollution free.It has been used as domestic source of energy.It has been a renewable source of energy.It has been produced by the tidal waves, thus can be produced effective and in need.

Some of the disadvantages of hydro-kinetic energy has been:

Application of water bodies affects the marine environment.It has been producing low BOD and thereby affects the water quality.Conditions such as drought result in the affected electricity production.

For more information about hydro-kinetic energy, refer to the link:

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Answer:

Some advantages to using hydrokinetic energy are that it can be used without mining materials, it is not associated with waste production, and that it does not contribute to air pollution. The main disadvantage to using hydrokinetic energy is the fact that it uses waves and tides as an energy source. This technology could not be used in all locations.

Explanation:

got it on edge sorry for the late response

In which of the following reactions is chlorine (Cl) oxidized? Br2 2Cl⒠→ Cl2 2Br⒠Cl2 2e⒠→ 2Cl⒠2ClO3⒠12H → Cl2 6H2O 2Na Cl2 → 2NaCl.

Answers

The reaction in which Cl has been oxidized is [tex]\rm Br_2\;+\;2\;Cl^-\;\rightarrow\;Cl_2\;+\;2\;Br^-[/tex]. Thus, option A is correct.

In a reaction, the oxidation has been defined as the loss of electrons by the atom, while reduction has been depicted as the gain of electrons.

The loss of electrons imparts a positive charge to the atom, while the gain of electrons imparts a negative charge to the atom.

In the following reactions, the Cl has been given as:

[tex]\rm Br_2\;+\;2\;Cl^-\;\rightarrow\;Cl_2\;+\;2\;Br^-[/tex]

The chlorine has loses the electron and is converted to diatomic molecule. Thus, the Cl has been oxidized. The oxidation state of Cl has also been increased from -1 to 0.

[tex]\rm Cl_2\;+\;2\;e^-\;\rightarrow\;2\;Cl^-[/tex]

The chlorine gains 2 electrons in the reaction and has been reduced.

[tex]\rm 2\;ClO_3^-\;+\;12\;H^+\;\rightarrow\;Cl_2\;+6\;H_2O[/tex]

There has been no change in the oxidation state of chlorine. Thus, Cl has not been oxidized.

[tex]\rm 2\;Na\;+\;Cl_2\;\rightarrow\;2\;NaCl[/tex]

The chlorine gains electron and has been converted to the Cl ion. With the gain of electrons, Cl has been reduced.

The reaction in which Cl has been oxidized is [tex]\rm Br_2\;+\;2\;Cl^-\;\rightarrow\;Cl_2\;+\;2\;Br^-[/tex]. Thus, option A is correct.

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The pH scale is used to tell if a substance
is an acid or base. Substances with a pH
of 7 are neutral. An acid is anything
below 7 and a base is anything above
7.What would a household cleaner with a
pH of 10 be considered on the pH scale?

Answers

Answer:

Explanation:

pH > 7   as 10 is more than 7

The cleaner is very corrosive.

It is a moderately basic. If it was 12 that would make it much more basic (100 times more basic).

28) what is the number of oxygen atoms in the formula unit of Ca3(PO4)2?​

Answers

Answer:

4.816x10²⁴atoms

Explanation:

the number of moles of oxygen is 8

let x be number of oxygen atoms

recall that 1 mole=6.02x10^23 atoms

therefore, 8 moles =x

cross multiply

8 x 6.02 x 10^23 = x

x = 4.816 x 10²⁴atoms

Deval drew the models of particles in a substance shown below. Which model best represents the particles in solid

Answers

Answer:

it would be the second one thank me later

Explanation:

Given the speed of light as 3.00 x 10° m/s, calculate the
wavelength of the electromagnetic radiation whose frequency
is 9.500 x 101° Hz.

Answers

Answer:

the answer is mabye 30 I didnt understand

Two goldfish different parents.One fish has a split tail and the other does not.Why do the goldfish have tails with different shapes?

a.Each goldfish has a different tail shape because offspring from different parents will have different tail shapes.

b.Each goldfish has a different tail shape because they have different versions of the gene for tail shape that connect together to make different tail shapes.

c.The goldfish have different versions of the gene for tail shape.The genes are split inside one goldfish's tail but not inside the other's

The goldfish have different versions of the gene for tail shape,which instuct for different proteins that connect in different ways to make different tail shapes.

Answers

Answer:

A I believe is your best choice.

Explanation:

Rebekah finds that a solution of sugar in water has a volume of 1. 32 fl. Oz. How should she report this amount using the metric system? (1 fl. Oz. = 29. 6 mL) 0. 403 m 1. 40 qt 37. 5 g 39. 1 mL.

Answers

Rebekah reports the volume of sugar solution using metric system as 39.1 mL. Thus, option D is correct.

The metric system has been the measurement system introduced in 1790s. The system has mediated the units for the measurement of volume, mass, length.

The volume has been the space that has been occupied by matter. The volume can be denoted with SI unit L. However, the another accepted unit for volume has been mL.

Thus, the volume of sugar solution has been reported in mL.

The given sugar solution has volume of 1.32 fl. Oz

The volume in mL can be given as:

[tex]\rm 1\;fl\;Oz=29.6\;mL\\1.32\;fl\;Oz=1.32\;\times\;29.6\;mL\\1.32\;fl\;Oz=39.1\;mL[/tex]

The volume of the sugar solution reported by Rebekah on the metric scale has been 39.1 mL. Thus, option D is correct.

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How many Hydrogen atoms are required to satisfy Oxygen during bonding

Answers

Answer:

2 hydrogen atoms

Explanation:

I’m sure it’s two hydrogen atoms

3. Type: MT
Match the term to the correct definition
1. Homogeneous mixture
a. same throughout
2. Heterogeneous mixture
b. different throughout

Answers

Homogeneous mixture - same throughout

Heterogeneous mixture - different throughout

Answer:  Homogeneous Mixture : B(different throughout)

Heterogeneous Mixture : A(same throughout)

Conversion of units of temperature

Answers

Answer:

1. -5

2. 88.7

3. -23.3333

4. 126.5

5. 69.8

6. 30.61111

7. 118.4

8. 275

9. 94.82

10. 44.6

Explanation:

Answer:

here you go

Explanation:

1.-5

2.88.7

3.23.333

4.126.5

5.69.8

6.30.6111

7.118.4

8.275

9.94.82

10.44.6

All three types of rock form in which earth layer?

Answers

Answer:

Lithosphere

Explanation:

All three types of rock make up the Earth's lithosphere, the outermost layer. The lithosphere averages about 100 kilometers in thickness.

On the spectrum, which section has the longest wavelength and the shortest wavelength? (2 answers for this question)

Answers

Answer:

Radio waves, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays are all types of electromagnetic radiation. Radio waves have the longest wavelength, and gamma rays have the shortest wavelength.Hope i help you

URGENT PLEASE HELP
What most likely happens when a sodium atom comes near an atom having seven valence electrons?

Answers

Answer:

7 Electrons

Explanation:

What it is fill its valence shell, it would need to acquire 7 electrons - a difficult task for a metal like sodium that is a known electron-loser. So unlike fluorine and oxygen, sodium acquires a full octet by losing electrons and emptying out its outermost shell.

The percent of attacks on the dark-colored mouse models is how many times greater than the percent of attacks on light-colored models

Answers

The number of times the percentage of attacks on the dark-colored mouse is greater than the percentage of attacks on light-colored mouse is four (4) times.

Let the percent of attacks on the dark-colored mouse be D.Let the percent of attacks on light-colored mouse be L.

Given the following data:

Light-colored mouse models = 20 percentDark-colored mouse models = 80 percent

To determine the number of times the percentage of attacks on the dark-colored mouse is greater than the percentage of attacks on light-colored mouse.

Therefore, we would simply divide the percentage for the dark-colored mouse by the percentage for the light-colored mouse as follows:

[tex]Number \;of\;times = \frac{D}{L}[/tex]

Substituting the given parameters into the formula, we have;

[tex]Number \;of\;times = \frac{80}{20}[/tex]

Number of times = 4 times.

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At room temperature Bromine is a liquid and lodine is a solid, what can be inferred
about the intermolecular forces of these two elements?

Answers

Answer:

Explanation:

The intermolecular forces are stronger in Iodine, meaning that its molecules are stronger and can hold that solid structure at room temperature, where Bromine cannot due to its IMF's being weaker.

How many moles of aluminum are needed to react completely with 2.1 moles of FeO? 2Al(s) + 3FeO(s) 3Fe(s) + Al2O3(s)

Answers

Answer:

1,4 mol

Explanation:

2 mol of Al reacts with 3 mol of FeO so for 2.1 mol of FeO you need 2 x 2.1 / 3 = 1.4mol

Choose the best answer.
What is the sum?
2/3+7/15
O 14/15
O1/2
O1 2/15
O3/5

Answers

Answer:

1 2/15

Explanation:

2/3 + 7/15 = 17/15 =1 2/15

write a balanced equation for the formation of co2 g from c s and o2 g

Answers

Answer:

C (s) + O2 (g) > CO2 (g)

That's what I got

Which description is not a property of an acid?
1. Slimy feel
2. Corrosive
3. Sour taste
4. Dissolves metals

Answers

Answer:

Slimy Feel

Explanation:

Acid usually doesn't have a Slimy Feel to it.

Acids don’t have a slimy feel

Difference between Laboratory Thermometer and Clinical Thermometer.​

Answers

Explanation:

Can you please mark me the brillantest?

The difference between a laboratory thermometer and a clinical thermometer is that a clinical thermometer is used to measure body temperature, however a laboratory thermometer is not used for purpose of measuring body temperature
The clinical thermometer can be titled while reading the temperature values whereas a laboratory thermometer needs to be kept upright.

Question 12 of 35
Which two specialized structures allow amphibians to live on land?
O A. Gills
B. Lungs
C. Legs
D. Tail
SUBMIETI

Answers

Answer:

B and C

Explanation:

Most animals that live underwater have have gills and tails and vise versa hope this helps!

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The electron configuration of a cation with a 2+ charge is shown below.
1s22s22p63s23p6
What is the electron configuration for the ion's neutral parent atom? The atom is a main group
element. Name the group that the parent atom likely belongs to on the Periodic Table and identify
one chemical property of the parent atom.

Answers

The electron configuration for the ion's neutral parent atom is

1s²2s²2p⁶3s²3p⁶4s²

It belongs to group 2 on the periodic table and one of its chemical properties is, it has a density of 1.54 g/cm³

From the question,

The cation has a charge of 2+. This means the neutral atom lost 2 electrons.

From the given electron configuration, the cation has 18 electrons.

Therefore, the neutral atom of ion will have 20 electrons.

∴ The electron configuration for the ion's neutral parent atom is

1s²2s²2p⁶3s²3p⁶4s²

The atom belongs to group 2 on the periodic table.

One chemical property of the parent atom

Its density is 1.54 g/cm³

Hence,  The electron configuration for the ion's neutral parent atom is

1s²2s²2p⁶3s²3p⁶4s²

It belongs to group 2 on the periodic table and one of its chemical properties is, it has a density of 1.54 g/cm³

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In which one element replaces a similar element in a compound

Answers

Question:-

In which one element replaces a similar element in a compound?

Answer:-

A single-replacement reaction

Explanation:-

A single-replacement reaction is a reaction in which one element of a compound is replaced by another.

what is the Conversion of products into reactants

Answers

Answer:

In a chemical reaction, substances (elements and/or compounds) called reactants are changed into other substances (compounds and/or elements) called products. You can't change one element into another in a chemical reaction — that happens in nuclear reactions.

Explanation:

Explanation:

Thus, reactions in which products can be converted to reactant is called Reversible reaction.

Which of the following is true for the percentage yield of a reaction?

А. It is the combined yield from the excess reactant and the limiting reactant.

B. It is the calculated yield of the product based on stoichiometry alone.

C. It is calculated based on stoichiometry as well as experimentation.

D. It is the yield of the product from the limiting reactant alone.​

Answers

Answer:

It is always less than the theoretical yield

Explanation:

For many chemical reactions, the actual yield is usually less than the theoretical yield. This is due to possible loss in the process or inefficiency of the chemical reaction.

The chemical equation below shows the burning of magnesium (Mg) with oxygen (O2) to form magnesium oxide (MgO). 2Mg O2 Right arrow. 2MgO The molar mass of O2 is 32. 0 g/mol. What mass, in grams, of O2 is required to react completely with 4. 00 mol of Mg? 2. 00 64. 0 128 256.

Answers

Answer:

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The mass of oxygen required for complete utilization of 4 mol of Mg has been 64 g. Thus, option B is correct.

The balanced equation for the reaction has been:

[tex]\rm 2\;Mg\;+\;O_2\;\rightarrow\;2\;MgO[/tex]

From the balanced chemical equation, for complete utilization of 2 moles of Mg, 1 moles of oxygen has been used.

The given moles of Mg has been 4 mol. The moles of oxygen required can be given as:

[tex]\rm 2\;mol\;Mg=1\;mol\;O_2\\4\;mol\;Mg=2\;mol\;O_2[/tex]

Thus, the moles of oxygen required has been 2 mol for complete utilization of 4 mol Mg.

The mass from moles can be calculated as:

[tex]\rm Mass=Moles\;\times\;molecular\;mass[/tex]

The molecular mass of oxygen has been 32 g/mol.

The mass of oxygen has been:

[tex]\rm Mass=2\;\times\;32\;g\\Mass=64\;g[/tex]

The mass of oxygen required for complete utilization of 4 mol of Mg has been 64 g. Thus, option B is correct.

For more information about the chemical equation,refer to the link:

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Help this is due today!!!

Answers

Answer:

a) Fe

b) Fe

c) Fe

Explanation:

When using their stoichiometric ratios, in all of the the iron will run out before the oxygen, making the iron the limiting reactant.

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