The percentage of an iodine-131 sample that will remain after 40.20 days is 3.125%
We'll begin by calculating the number of half-lives that has elapsed. This can be obtained as follow:Half-life (t½) = 8.040 days.
Time (t) = 40.20 days
Number of half-lives (n) =?[tex]n = \frac{t}{t_{1/2}} \\\\n = \frac{40.20}{8.040}\\\\[/tex]
n = 5Thus, 5 half-lives has elapsed.
Finally, we shall determine the percentage of an iodine-131 sample that remains. This can be obtained as follow:Number of half-lives (n) = 5
Percentage remaining =?[tex]N = \frac{1}{2^{n} } * N_{0} \\\\N = \frac{1}{2^{5} } * N_{0} \\\\N = \frac{1}{32} * N_{0}\\\\[/tex]
Divide both side by N₀
[tex]\frac{N}{N_{0}} = \frac{1}{32} \\\\\frac{N}{N_{0}} = 0.03125\\\\[/tex]
Multiply by 100 to express in percent
[tex]\frac{N}{N_{0}} =[/tex] 0.0312 × 100
= 3.125%Therefore, the percentage of an iodine-131 sample that remains is 3.125%
NOTE:[tex]\frac{N}{N_{0}}[/tex] => Fraction remaining
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What the cm and mm for this
Answer:
5 cm and 50 mm
Explanation:
1 cm = 10 mm
So 5cm = 50 mm
what is the expected charge for nitrogen in an ionic compound?
Answer:
3−
Thus, a nitrogen atom will form an anion with three more electrons than protons and a charge of 3−.
Explanation:
a chemist has synthesized a greenish-yellow gaseous compound that contains only chlorine and oxygen and has a density of 7.71 g/l at 36.0 degrees celsius and 2188.8 mm hg. what is the molar mass of the compound?
b.c10²
i dont know if it is right sorry if isn't
Why is milk white? and there is no diffrent in various mamals?
Answer:
Milk is naturally a white substance due to the make-up of water and other components including fat and protein that mix together to form tiny particles which reflect light. There is a difference in mammals milk; for example, hippos milk is pink.
Explanation:
Can some one please give me the answers
Is this statement true? “Are acids are aqueous therefore all aqueous solutions are acids”
A scientist discovers an object in the solar system. She describes it as bigger
than an asteroid, smaller than Mercury, and farther from the sun than Neptune.
What kind of object could it be? Explain.
Answer:
Pluto I think it's the ans
Which statement is always true when nuclear fusion occurs?(1 point)
The total number of protons and neutrons in each nucleus remains constant.
The number of protons in the resulting nucleus is double that of a starting nucleus.
The combined number of protons and neutrons remains constant.
The number of protons in the resulting nucleus is less than in each starting nucleus.
Use the equation to answer the question.
21H+ 21H→ 42H+energy
Which statement best describes the mass numbers of the atoms in the reaction?
(1 point)
There are two atoms with mass numbers of 2.
There is one atom with a mass number of 2.
There are two atoms with mass numbers of 1.
There is one atom with a mass number of 1.
Which fact is true during a fission chain reaction?(1 point)
The number of freely-moving neutrons increases over time.
The total number of protons will decrease over time.
The total number of protons will increase over time.
The number of freely-moving neutrons decreases over time.
Plsss help
Answer: Which statement is always true when nuclear fusion occurs: The combined number of protons and neutrons remains constant.
21H+ 21H→ 42H+energy
Which statement best describes the mass numbers of the atoms in the reaction? There are two atoms with mass numbers of 2.
Which fact is true during a fission chain reaction? The number of freely-moving neutrons increases over time.
Explanation:
The statement which is always true when nuclear fusion occurs is "the combined number of protons and neutrons remains constant".
What is nuclear fusion?Nuclear fusion is a type of reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles.
The equation 21H+ 21H→ 42H+energy represent that there are two atoms with mass numbers of 2.The true statement during a fission chain reaction is "the number of freely-moving neutrons increases over time".Fission chain reaction is a process in which neutrons released in fission produce an additional fission in at least one further nucleus. This nucleus in turn produces neutrons, and the process repeats.
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Have an upcoming test (that was leaked) and need to figure out Fluorine and astatine similarities please reply ASAP
Answer:
They both classify as halogens they are both in the fluorine family and their both in group 17 on the periodic table
Explanation:
That's all I could come up with
Chemical properties of earth metals-
Answer:
highly reactive at standard temperature and pressurereadily lose their outermost electron to form cations with a charge of +1help me with this:(((
Answer:
13. A. Kinetic energy increases
14. A. Kinetic energy
15. B. is not transferable
Sorry if I got any wrong, they should be all correct. I tryed.
what is irriversable change
Answer:
Paper burning
Explanation:
A certain source emits radiation of wavelength 525 nm, What is the energy, in j.
Answer:
[tex]3.7837 \times {10}^{ - 19} j[/tex]
Explanation:
[tex]e = \frac{hc}{ \lambda} \\ where \: h \: = plancks \: constant \\ and \: c = speed \: of \: light[/tex]
Planck constant value: h = [tex]6.62606957 \times {10}^{ - 34} j \: s\: [/tex]
speed of light constant: c = [tex]299,792,458 \frac{m}{ s} [/tex]
[tex]hc = 6.62606957 \times {10}^{ - 34} j \: s\: \: \times \\ 299792458 = 1.98645 \times {10}^{ - 25} j \: m[/tex]
Divide the wavelength in nanometers by 10^9 to calculate the value in meters.
[tex] \frac{525}{ {10}^{9} } = 5.25 \times {10}^{ - 7} m[/tex]
[tex]e = \frac{hc}{ \lambda} \\ = \frac{1.98645 \times {10}^{ - 25} j \: m}{ 5.25 \times {10}^{ - 7} m} [/tex]
[tex] = 3.7837 \times {10}^{ - 19} j[/tex]
Which of the following methods would be the best method for separating oil from water?
Lime water alkali or acid
Answer:
Ca(OH)2 chemical of lime water.
it is alkali in nature if it is only lime then it is an example of critic acid and it is know as. acid
lime wate is alikali
limes is acid
Explanation:
mark me brainlistAnswer:
Alkali
Explanation:
Limewater is the calcium hydroxide. It is Alkali
Explain the role of sunlight in the process of photosynthesis
Answer:
When the sun's rays shine down on a plant, the chlorophyll capture the energy from the sun and use it during photosynthesis to make sugars. Sugar is the energy source for plants, that is why sunlight and photosynthesis is so important
The energy from light causes a chemical reaction that breaks down the molecules of carbon dioxide and water and reorganizes them to make the sugar (glucose) and oxygen gas.
The burning of a 0.37 g potato chip causes the temperature of 58.18 g of water in a soda can calorimeter to increase from 21.5℃ to 28.1℃. Calculate the amount of heat absorbed by the water. The specific heat of water is 4.184 J/g⋅℃. Express this answer in both Joules and Nutritional Calories.
The amount of heat absorbed by the water is 1606.6 J (383.99 Calories )
We'll begin by calculating the change in the temperature of the water.
Initial temperature (T₁) = 21.5 °C
Final temperature (T₂) = 28.1 °C
Change in temperature (ΔT) =?ΔT = T₂ – T₁
ΔT = 28.1 – 21.5
ΔT = 6.6 °CFinally, we shall determine the heat absorbed by the water. This can be obtained as follow:Mass of water (M) = 58.18 g
Change in temperature (ΔT) = 6.6 °C
Specific heat capacity of water (C) = 4.184 J/gºC
Heat absorbed (Q) =?Q = MCΔT
Q = 58.18 × 4.184 × 6.6
Q = 1606.6 JDivide by 4.184 to express in Calories
Q = 1606.6 / 4.184
Q = 383.99 CaloriesTherefore, the amount of heat absorbed by the water is 1606.6 J (383.99 Calories )
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What is The particle in the nucleus of an atom that has the same mass of protons but no net charge
Answer:
neutron
Explanation:
neutron and proton has approximately the same mass .proton is positively charged but neutron has no charge
Complete the following nuclear equation.
Answer:
oxygen-17
Explanation:
sum of the mass numbers and sum of the atomic numbers should be same in the both sides respectively
What protects humans from harmful UV-B rays?
Answer:
Stay in the shade, especially during midday hours.
Wear clothes that cover your arms and legs.
Consider options to protect your children.
Wear a wide brim hat to shade your face, head, ears, and neck.
Wear wraparound sunglasses that block both UVA and UVB rays.
Explanation:
CAN YOU GIVE ME BRAINLIEST
lava is a hot liquid rock. when lava flows over solid ground beneath it increases in temperature. what happens to the molecules in the solid ground when the temperature is increasing?
Answer:
Lava is hot liquid rock. When lava flows over solid ground, the solid ground beneath it increases in temperature. What happens to the molecules in the solid ground when the temperature is increasing? The energy of the molecules in the ground decreases.
Which of the following are not mixtures: milk, tin, sulfur, cough linctus, brass, gold?
Answer:
[tex]tin \: sulphar gold \: are \: not \: mixture \: \\ they \: are \: elements \: \: others \: are \: mixture \\ thank \: you[/tex]
Tin, sulfur, and gold are not a mixture because they are pure elements.
What are the mixture and pure substance?Pure substances can be described as elements that cannot be broken down into simple substances because they have only one type of atom in the whole composition.
A pure substance can be described as composed of two or more elements that are chemically combined and have a set composition such kind of pure substance is known as a compound.
A mixture can be described as made up of two or more different substances which are just physically combined but not chemically. A mixture can be separated into its initial components.
The composition of a heterogeneous mixture is non-uniform throughout the mixture while the composition of a homogeneous mixture is always the same in the entire mixture.
Therefore, tin, sulfur, and gold are pure elements, not a mixture.
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4.
How would the electrons in a calcium atom (atomic number=12) arrange
themselves into different energy levels?
Answer:
Viewed simply, electrons are arranged in shells around an atom's nucleus. Electrons closest to the nucleus will have the lowest energy. Electrons further away from the nucleus will have higher energy. ... In a more realistic model, electrons move in atomic orbitals, or subshells.
Explanation:
Viewed simply, electrons are arranged in shells around an atom's nucleus. Electrons closest to the nucleus will have the lowest energy. Electrons further away from the nucleus will have higher energy. ... In a more realistic model, electrons move in atomic orbitals, or subshells.
A sample of gas has a volume
of 0.325 L at 55°C and a
pressure of 1.5 atm. At what
temperature does this gas have
a volume of 0.750 L and a
pressure of 2.5 atm??
0.75x2.5x328/(0.325x1.5)
=1261.5K
Consider the formula of the compound, calcium chloride. Select all the statements that apply to this image.
a) A covalent compound is formed
b) Chlorine becomes a negative ion
c) The chemical formula is CaCl2
d) Calcium transfers electrons to the chlorine atoms
e) The subscript 2, is used to balance the charges
Answer: Its B,C,D, and E
Explanation:
The correct statements about the compound calcium chloride are Chlorine becomes a negative ion, The chemical formula is CaCl₂, Calcium transfers electrons to the chlorine atoms and The subscript 2 is used to balance the charge.
Hence, Option B, C, D and E are correct.
Calcium ChlorideCalcium chloride is a crystalline white substance which is soluble in water. It is the chloride salt of calcium. The chemical formula of calcium chloride is CaCl₂. In calcium chloride, Calcium atom has two valence electrons.
Now lets check all statements one by one
Option (A): Calcium chloride is a ionic compound. Here calcium transfers its valence electrons to both chlorine atoms.
So, statement A is incorrect.
Option (B): In calcium chloride each chlorine atom gains 1 electron and we get a negatively charged ion Cl⁻.
So, statement B is correct.
Option (C): In Calcium chloride the valency of calcium is +2 and the valency of chlorine is -1. So the chemical formula is CaCl₂.
So, statement C is correct.
Option (D): In calcium chloride calcium transfer its two valence electrons to both the chlorine atoms.
So, statement D is correct.
Option (E): In calcium chloride the subscript 2 is used to balance the charge. The subscript show the number of atoms in compound.
So, statement E is correct.
Thus, from the above conclusions we can say that The correct statements about the compound calcium chloride are Chlorine becomes a negative ion, The chemical formula is CaCl₂, Calcium transfers electrons to the chlorine atoms and The subscript 2 is used to balance the charge.
Hence, Option B, C, D and E are correct.
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What is the Electron dot diagram for beryllium and carbon
Answer:
Beryllium has 2 dots and Carbon has 4
What is carbon so good for forming the structure of life
Answer:
Because its the basic building block of life
Explanation:
Carbon is essential to life since it is present in nearly all molecules in the body. like, sugars, DNA, proteins, lipids, and so on. Except for water though.
When compared to the standard hydrogen electrode, zinc has a reduction potential of -0.762 volts and copper a reduction potential of + 0.342 volts. What is the reduction potential when zinc and copper are connected to one another?
+0.420 volts
-0.420 volts
+1.104 volts
-1.104 volts
Answer:
When compared to the standard hydrogen electrode, zinc has a reduction potential of -0.762 volts and copper a reduction potential of + 0.342 volts. What is the reduction potential when zinc and copper are connected to one another? Standard Santand Inc ар -40 INC IM IM Z IM ಅವಳ ದdಂಗpa volts 0.420- volts 0.420- volts 0.420- volts 1.104+
Explanation:
Btw brainliest me plss
Using evidence from the passage, explain how the population of moths changed after the Industrial Revolution began.
Answer:
After the pollution from the Industrial Revolution started affecting trees, most of the collected peppered moths were of the dark form. ... They were eaten by birds more and more, while the rare dark colored moths blended in better on the darker trees. This made the dark colored moths have a higher survival rate.Viết các phương trình phản ứng xảy ra khi cho lượng dư dung dịch H2XO4 loãng lần lượt
vào các chất sau: Fe, KOH, MgO, Fe3O4 , FeS, KHCO3, BaCl2, Al(OH)3.
Answer:
mcsdfltghjktym,mxsdjqeury46yuiejlm,x.dfkrut9ejv7uahjfm,clo95yijmfgnhgkm,vfwosafijj
Explanation:
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