Recall that your hypothesis is that these values are the fraction of atoms that are still radioactive after n half-life cycles. Record in the appropriate blanks.
Answers
B=0.25
C=0.125
D=0.015625
E=0.00390625
Answer : A= 0.5, B = 0.25 , C = 0.125, D = 0.015625 and E = 0.00390625
Explanation :
Half life of a substance is defined as the amount of time taken by the substance to reduce to half of its original amount.
Here n represents the number of half lives.
The amount of substance that remains after n half lives can be calculated using the given formula, [tex] 0.5^{n} [/tex]
So when we have n =1,
Fraction of substance that remains = 0.5¹ = 0.5.
That means after first half life over, the amount of substance that remains is 0.5 times that of original.
Therefore we have A = 0.5
When n = 2, we have 0.5² = 0.25
So when 2 half lives are over, the amount of substance that remains is 0.25 times that of original
Therefore B = 0.25
When n = 3, we have 0.5³ = 0.125
So when 3 half lives are over, the amount of substance that remains is 0.125 times that of original.
Therefore we have C = 0.125
When n = 6 , we have 0.5⁶ = 0.015625
So D = 0.015625
When n = 8, we have 0.5⁸ = 0.00390625
Therefore E = 0.00390625
The values for A, B, C, D and E are 0.5, 0.25, 0.125, 0.015625 and 0.00390625 respectively.
Related Questions
Scientists have been able to insert genes from bacteria into the DNA of corn plants. This gives some species of corn additional resistance to pests. Why would this breakthrough be beneficial to humans?
A. Farmers will increase their use of chemicals that kill pests.
B.Less chemical residue will be found in the air and water.
C.Bacteria will flourish inside the corn plants.
D.The corn will cause illness in humans or animals.
E.The amount of corn produced per acre of farmland will decrease.
Answers
Scientists have been able to insert genes from bacteria into the DNA of corn plants. This gives some species of corn additional resistance to pests.
This would breakthrough be beneficial to humans as " less chemical residue will be found in the air and water"
What is DNA?Deoxyribonucleic acid (DNA) is just a polymer made up of two polynucleotide chains whose coil around with each other to create a double helix which carries genetic instructions including all living things and viruses' formation, function, growth, but also reproduction.
What is chemical residue?The remnants of a chemical or even its decomposition products may remain in or on prepared produce and are referred to as chemical residues. Chemical residues could form as a result of directly processing produce with either a chemical product or as a result of chemical exposure.
Therefore, the correct answer will be option (B).
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Number of moles in 11.82 g gold
Answers
Final answer:
The number of moles in 11.82 g of gold is calculated by dividing the mass of the gold by its molar mass. The atomic weight of gold is approximately 197 g/mol, so the calculation is 11.82 g divided by 197 g/mol.
Explanation:
The calculation of the number of moles in a given mass of a substance is a fundamental concept in chemistry. The number of moles (n) can be determined using the formula:
n = mass (g) / molar mass (g/mol)
For gold (Au), the atomic weight is approximately 197 g/mol, which is its molar mass. Therefore, to find the number of moles in 11.82 g of gold, you divide the mass of the gold by the molar mass of gold as follows:
n = 11.82 g / 197 g/mol
This calculation will give you the number of moles of gold in the sample. The density of gold and Avogadro's number are not directly needed for this calculation, but they are commonly referenced when discussing the properties of elements and the mole concept.
1. Versions of atoms with different amounts of neutrons are called ________.
Answers
How many moles of Pb(NO3)2 are required if 8 moles of PbCI2 are produced?
Answers
Pb(NO₃)₂ + 2 HCl → PbCl₂ + 2 HNO₃
According to equation,
1 mole of PbCl₂ is formed by = 1 mole of Pb(NO₃)₂
So,
8 moles of PbCl₂ will be produced by = X moles of Pb(NO₃)₂
Solving for X,
X = (8 mol × 1 mol) ÷ 1 mol
X = 8 mol of Pb(NO₃)₂
Result:
8 mol of Pb(NO₃)₂ are required to produce 8 moles of PbCl₂.
Which nuclear emission has the greatest penetrating power?
b. beta particle
a. proton
c. gamma radiation
d. positron
Answers
Answer:gamma radiation
Explanation:
Among the nuclear emissions including proton, beta particle, positron and gamma radiation, gamma radiation has the greatest penetrating power. It needs dense materials like lead or concrete to be shielded.
Explanation:Of the nuclear emissions listed: a. proton, b. beta particle, c. gamma radiation, and d. positron, the one with the greatest penetrating power is c. gamma radiation. Unlike other particles, gamma radiation is a type of electromagnetic radiation, similar to X-rays. This means it is not a charged particle, allowing it to penetrate materials more easily.
For instance, alpha and beta particles would be blocked by a piece of paper or the surface of the human skin, but gamma rays can penetrate much deeper, requiring dense materials like lead or concrete for shielding.
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What is the ph of an acetic acid solution if 10 drops are titrated with 70 drops of a 0.65 m koh solution? (ka for acetic acid = 1.8 x 10-5)?
Answers
[KOH] = 0.65 M
[OH] = 0.65 M
Dilute your mom
[OH]Dil= 0.65 M * 70/80 = 0.56875 M
pH = 5.4
Natural gas is primarily composed of ________. natural gas is primarily composed of ________. methane sulfur dioxide nitrogen oxygen nitrite
Answers
Natural gas is a naturally occurring hydrocarbon mixture which is primarily composed of Methane(CH4), but it also contains ethane,propane and heavier hydrocarbon. In addition it contain small amount of nitrogen, carbon dioxide,hydrogen sulfide and traces amount of water.
Natural gas is primarily composed of methane, which is a colorless, odorless, and highly flammable hydrocarbon produced through the natural decomposition of organic materials.
Explanation:Natural gas is primarily composed of methane. Methane, abbreviated as CH4 or carbon tetrahydrate, is a hydrocarbon that is a main component of natural gas. The natural process of decomposition of organic materials in the lack of oxygen forms methane. This gas is colorless, odorless, and highly flammable. Ensuring safety for use in homes, a rotten egg-like smell is often added to it.
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What is the correct form of the equilibrium constant for the reaction of hydrogen and oxygen to form water? the equation is:?
Answers
K = [H₂O]² / [O₂] · [H₂]².
[H₂O] is equilibrium concentration of water.
[O₂] is equilibrium concentration of molecule of oxygen.
[H₂] is equilibrium concentration of molecule of molecule of hydrogen.
The substances on the right side of the reaction are written at the top of the equilibrium constant expression and those on the left at the bottom.
Match the term with its definition. A. Bed load A strip of land next to a river that is often very fertile B. Headwater The beginning of a river C. Suspended load Large boulders carried along by a river D. Flood plain Small rocks carried along by a river
Answers
Bed load - Large boulders carried along by a river
Headwater - The beginning of a river
Suspended load - Small rocks carried along by a river
Flood plain - A strip of land next to a river that is often very fertile
(APEX Verified 2020)
If 22.50 mL of a sodium hydroxide solution is necessary to neutralize 18.50 mL of a 0.1430 M HNO3 solution, what is the concentration of the NaOH? (Report your answer in molarity.)
Answers
calculate the moles of HNO3
moles =molarity x volume
=18.50 x0.1430 = 2.6455 moles
write the reacting equation
that is
NaOH + HNO3 =NaNO3 +H2O
by use mole ratio between NaOH: HNO3 the moles of NaOH is also 2.6455moles
concentration is therefore moles/volume
= 2.6455/ 22.50 = 0.118M
what happens when sulphur trioxide reacts with concentrated sulphur acid ?
Answers
I believe the answer you're looking for is that redox reaction takes place between the two substances, forming sulphur dioxide and water.
Sulphur is oxidised to sulphur dioxide by hot and concentrated sulphuric acid, and the acid also gets reduced to the same product (sulphur oxide) by sulphur.
Hope this helps! :)
A sample of oxygen gas has a volume of 150. milliliters at 300 k. if the pressure of the sample is held constant and the temperature is raised to 600 k, the new volume of the sample will be
Answers
Answer:
The new volume of the sample will be 300 milliliteres
Explanation:
We were given the following;
Initial Volume (V1) = 150ml
Initial Temperature (T1) = 300K
Final Temperature (T2) = 600K
Final Volume (V2) = ?
Pressure is held constant.
The law applicable in solving this question is that of Charle's law. This law states that the volume of a fixed mass of gas varies proportional to the temperature at constant pressure.
The formula is given as;
[tex]\frac{V1 }{T1} = \frac{V2 }{T2}[/tex]
Solving for V2. we have;
[tex]V2 = \frac{V1T2}{T1}[/tex]
V2 = ( 150 * 600) / 300
V2 = 300 ml
Suppose you wish to make 0.879 l of 0.250 m silver nitrate by diluting a stock solution of 0.675 m silver nitrate. how many milliliters of the stock solution would you need to use?
Answers
Answer is: 325.5 mL of the stock solution.
c₁(AgNO₃) = 0.675 M.
V₂(AgNO₃) = 0.879 L.
c₂(AgNO₃) = 0.250 M.
V₁(AgNO₃) = ?
c₁ -
original concentration of the solution, before it gets diluted.
c₂
- final concentration of the solution, after dilution.
V₁
- volume to
be diluted.
V₂ - final volume after
dilution.
c₁ · V₁ = c₂
· V₂.
V₁(AgNO₃) = c₂ · V₂ ÷ c₁.
V₁(AgNO₃) = 0.250 M · 0.879 L ÷ 0.675 M.
V₁(AgNO₃) = 0.325 L · 1000 mL = 325 mL.
To make 0.879 l of 0.250 m silver nitrate from a 0.675 m stock solution, use the relationship between initial and final concentrations and volumes (M1V1 = M2V2). By substituting the given values and solving for V1, we can find the needed volume of the stock solution in liters and then convert that volume to milliliters by multiplying by 1000.
Explanation:To answer this question, we need to use the formula related to molarity (M = moles/liters), which is M1V1 = M2V2. It is a relationship between the initial concentration (M1) and volume (V1) of stock solution and the final concentration (M2) and volume (V2) of dilute solution.
In this case, the student wishes to make 0.879 l (V2) of 0.250 m (M2) silver nitrate by diluting a stock solution of 0.675 m (M1) silver nitrate. Substituting these values into the formula M1V1 = M2V2, we can find the volume of the stock solution needed (V1).
So, the calculation would be: (0.675 M) V1 = (0.250 M)(0.879 L).
To solve for V1, divide both sides by 0.675 M and the result is: V1 = (0.250 M)(0.879 L) / 0.675 M. This gives the volume of the stock solution you need to use in liters. To convert this to milliliters (since the question asked for the volume in milliliters), multiply by 1000.
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Which formulas and their respective names match? I) Li3N lithium nitride II) H2S hydrogen sulfite III) SO2 sulfur dioxide IV) AlF3 aluminum trifluoride
a.I and II
b.I and III
c.II and IV
d.I, II, and III?
Answers
hope this helps!!
Answer: The correct answer is Option b.
Explanation:
Ionic compound is defined as the compound which is formed by the complete transfer of electrons from one atom to another atom. These compounds are usually formed between metals and non-metals.
Covalent compounds are defined as the compounds which are formed by the sharing of electrons between two atoms. These compounds are formed between two non-metals.
The nomenclature of covalent compound is given by:
The less electronegative element is written first.The more electronegative element is written then, and a suffix is added with it. The suffix added is '-ide'.If atoms of an element is greater than 1, then prefixes are added which are 'mono' for 1 atom, 'di' for 2 atoms, 'tri' for 3 atoms and so on..The nomenclature of ionic compounds is given by:
Positive ion is written first.The negative ion is written next and a suffix is added at the end of the negative ion. The suffix added is '-ide'.For the given compounds:
(I) [tex]Li_3N[/tex]: This is an ionic compound and hence, its name is lithium nitride.
(II) [tex]H_2S[/tex]: This is a covalent compound and hence, its name is hydrogen sulfide.
(III) [tex]SO_2[/tex]: This is a covalent compound and hence, its name is sulfur dioxide.
(IV) [tex]AlF_3[/tex]: This is an ionic compound and hence, its name is aluminium fluoride.
Hence, the correct answer is Option b.
how are homologous structures such as forelimbs evidence for evolution ?
Answers
The study of the gradual change of an organism over a period of time is called evolution.
What is a homologous organ?Those structures of different species which have the same structure but the different function is called homologous organ.According to the question, the forelimbs are great evidence of evolution because the forelimbs give the ancestral connection between two species.
For example - the forelimbs of the bat and the human have the same structure but different functions.
Hence, the correct answer is mentioned above.
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Which noble gas would most likely form a compound with fluorine?
Answers
There are some exceptions to the rule that noble gases do not normally react with other elements to form compounds. Xe can combine with fluoride and oxide to form compounds.
What is noble gas ?Under standard conditions, the noble gases are all odorless, colorless, monatomic gases with very low chemical reactivity. Helium, neon, argon, krypton, xenon, and radioactive radon are the six naturally occurring noble gases.
In order of mass, the noble gases are helium, argon, krypton, xenon, and radon. Noble gases are so named because they are so magnificent that they do not react with anything in general. Because of this, they are also known as inert gases.
Noble gases, which are most commonly found as monatomic gases, have completely filled outer electron shells and thus have no desire to react with other elements, resulting in very few compounds.
Thus, There are some exceptions to the rule that noble gases do not normally react with other elements to form compounds.
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An enzyme is a protein that acts as a catalyst in a chemical reaction that takes place in a living thing true or false
Answers
which is the next logical step in balancing the given equation? CS2(1)+Cl2(g) CCl4(1) S2Cl2(1)
Answers
CS2(l) + Cl2(g) → CCl4(l) + S2Cl2(l)
While balancing the chemical reaction, care must be taken that number of atoms of reactant side is equal to number of reactant on product side.
In present case, There is 1 'C' atom of both reactant and product side
There are 2 'S' atoms on both reactant and product side.
However, there are 2 Cl atoms of reactant side, but 6 Cl atoms on product side.
Hence multiplying Cl2 by 3, would equal the number of Cl atoms on both the sides.
Thus, the balanced reaction is
CS2(l) + 3 Cl2(g) → CCl4(l) + S2Cl2(l)
Krypton-79 has a half-life of 35 hours. how many half-lives have passed after 105 hours?
Answers
if 1 half life = 35 hours
what about 105 hours = ? half-lives
= (1 half life x105 hours) /35 hours = 3 half-lives has passed after 105 hours
Three half-lives of Krypton-79, which has a half-life of 35 hours, have passed after a period of 105 hours.
Explanation:The concept underlying the question is related to the half-life of a radioactive substance. The half-life is the amount of time it takes for half of the substance to decay. Therefore, in the situation described in the question, the half-life of Krypton-79 is 35 hours.
If we have a time period of 105 hours, we can find the number of half-lives that have passed by dividing the total time by the half-life. So, 105 hours divided by 35 hours per half-life equals 3.
Therefore, 3 half-lives have passed in 105 hours for Krypton-79.
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What does the half-life of a radioisotope correspond to?
Answers
The half-life of a radioisotope corresponds to the length of time required for half of a sample of radioactive material to decay
What happens to the density of the core of a high-mass star as it collapses?
Answers
.
i hope this helps a little
.
zane
Why are valence electrons important? Why do elements bond? What are two ways elements complete their valence?
Answers
Valence electrons are the electrons present farthest from nucleus. These valence electrons are either transferred or shared during a reaction. Some elements like metals donate valence electrons in ionic compound formation, while some like Carbon mutually share thier valence electrons to make a covalent bond. Hence, it is the valence electrons that make any element reactive or unreactive.
Why do elements bond?
Elements react in order to gain stability. This stability is gained in the form of attaining noble gas configuration either by donating, gaining or mutually sharing their valence electrons.
What are two ways elements complete their valence?
The two ways are transfer of electrons and mutual sharing of electrons.
Example:
Sodium looses one valence electron to obtain Noble gas configuration of Neon which is more stable configuration.
Chlorine gains one electrons to obtain Noble Gas configuration of Argon which is more stable configuration.
Carbon mutually shares its four valence electrons with four atoms of Hydrogen having one electron per atom to complete its octet.
If the volume occupied by 0.500 mol of nitrogen gas at 0°C is 11.2 L, then the volume occupied by 2.00 mol of nitrogen gas at the same temperature and pressure will be:
A. the data given is not sufficient to determine the volume
B. 22.4 L
C. 44.8 L
D. the same as that occupied by 0.500 mol of nitrogen gas
Answers
[tex] \frac{V1}{n1} = \frac{V2}{n2} [/tex]
where V -volume , n - number of moles
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
substituting these values in the equation
[tex] \frac{11.2 L}{0.500 mol} = \frac{V}{2.00 mol} [/tex]
V = 44.8 L
answer is C. 44.8 L
Scientists have: (Select all that apply.)
a. observed amino acids forming spontaneously
b. demonstrated how amino acids can form from the environment
c. confirmed that the ultimate source of amino acids and proteins is from plants
d. not yet determined the source of amino acids
Answers
a. observed amino acids forming spontaneously
b. demonstrated how amino acids can form from the environment
c. confirmed that the ultimate source of amino acids and proteins is from plants
d. not yet determined the source of amino acids
The correct answers are:
Demonstrated how amino acids can form from the environment
Confirmed that the ultimate source of amino acids and proteins is from plants
A 20.9 ml sample of 0.267 m koh solution required 29.1 ml of aqueous acetic acid solution in a titration experiment. calculate the molarity of the acetic acid solution. answer in units of m.
Answers
calculate the moles of KOH used
moles =molarity x volume
= 20.9 x0.267 = 5.58 moles
write the reaction equation
KOH + CH3COOH = CH3COOK + H2O
since the reacting ratio between KOH to CH3COOH is 1:1 the moles of CH3COOH is also = 5.58 moles
molarity of CH3COOH = moles/volume
=5.58 /29.1 =0.192 M
what is the molarity of a 650. mL solution containing 64 grams of NaCl?
Answers
moles of NaCl = 64g x 1 mole/58.4 g = 1.095 moles NaCl
liters of solution = 650.0 ml x 1 L/1000 ml = 0.6500 liters
Molarity (M) of NaCl = moles/liters = 1.095 moles/0.6500 liters = 1.68 molar = 1.7 M (to 2 significant figures)
1. What is the pH of a 0.085 M solution of nitrous acid (HNO2) that has a Ka of 4.5 × 10-4?
2.21
5.33
3.35
4.42
Answers
HNO2 + H2O(l) ⇄ H3O^+ + NO2^-
Then
Ka = [H3O^+][NO2^-] / [HNO2]
If we let x represent the concentrations of [H3O^+] and [NO2^-] then
Ka = x^2 / [HNO2]
x = √(Ka * [HNO2])
x = √(4.5 × 10^-4 * 0.085)
x = 6.1846 x 10^-3 = [H3O+]
Therefore
pH = -log[H3O+]
pH = -log[6.1846 x 10^-3]
pH = 2.21
The answer to your question is 2.21.
Question 6 if a gas pressure gauge reads 32.0 psi, what is the pressure in inches of mercury? 165 in. hg 15.7 in. hg 65.1 in. hg 32.0 in. hg 6.19 in. hg
Answers
psi stands for pounds per square inch and in.Hg stands for inches in mercury.
1 psi is equivalent to 2.036 in.Hg
therefore 32.0 psi is equivalent to 2.036 in.Hg /psi x 32.0 psi = 65.1 in.Hg
therefore answer is 65.1 in. Hg
Answer:
65.1
Explanation:
The various components of crude oil are separated in a refinery based on differences in
Answers
Crude oil components are separated based on their boiling points using fractional distillation in a refinery.
Explanation:The various components of crude oil are separated in a refinery based on differences in their boiling points. This process, known as fractional distillation, takes advantage of the fact that different compounds in crude oil have different boiling points.
In a refinery, crude oil is heated in a furnace and the vaporized oil is then passed through a tall column called a fractionating column. As the vapor rises through the column, it cools down, and the compounds with higher boiling points condense and are collected at different levels in the column.
For example, at the bottom of the column, heavy compounds like bitumen and fuel oil are collected, while lighter compounds like gasoline and kerosene are collected at higher levels. This allows the refinery to separate and collect various components of crude oil for further processing.
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When a chemical reaction occurs, the physical and chemical properties of the reactants are the same as the properties of the products. truefalse?
Answers
In chemical reactions new substances are formed.
Answer:
False
Explanation:
You definitely won't see this nor need this but the Law of Conservation of Mass states that matter can neither be created nor destroyed in a chemical reaction.
I believe the answer is false