160 grams of I-131 were in the original sample if the half-life is 8 days.
What do you mean by half life?In a chemical reaction, the time taken for the concentration of that substance to become half of its initial value is called half-life. This term is used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay .
The amount left N after n half lives of a radioactive element with original amount N₀ is given as:
N= N₀ (1/2)ⁿ
Given, half life of Iodine-131 is 8 days
n= 40/8= 5
5= N₀ (1/2)⁵
N= 32 * 5
= 160 grams
Hence, the original amount amount of I-131 will be 160 grams.
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what trends can you see in the melting point and the boiling point of the halogens?
Answer:
The boiling points increase down the group.
Explanation:
The melting and boiling points increase down the group because of the van der Waals forces. The size of the molecules increases down the group. This increase in size means an increase in the strength of the van der Waals forces.
Answer:
Melting and Boiling Points (increases down the group)
The melting and boiling points increase down the group because of the van der Waals forces. The size of the molecules increases down the group. This increase in size means an increase in the strength of the van der Waals forces.
Explanation:
28. Which statement is INCORRECT regarding radiation?
a. Thicker materials offer better shielding against radiation
b. Gamma radiation is the only type that can cause health effects
c. Traveling further away from a source of radiation reduces your exposure
d. Each type of radiation can be detected by a device called a Geiger counter
Answer:
Radiation is energy. It can come from unstable atoms that undergo radioactive decay, or it can be produced by machines. Radiation travels from its source in the form of energy waves or energized particles. There are different forms of radiation and they have different properties and effects.
Related information in Spanish (Información relacionada en español)
On this page:
Ionizing and non-ionizing radiation
Electromagnetic spectrum
Types of ionizing radiation
Periodic Table
Non-Ionizing and Ionizing Radiation
There are two kinds of radiation: non-ionizing radiation and ionizing radiation.
Non-ionizing radiation has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough to remove electrons from atoms. Examples of this kind of radiation are radio waves, visible light and microwaves.
Ionizing radiation has so much energy it can knock electrons out of atoms, a process known as ionization. Ionizing radiation can affect the atoms in living things, so it poses a health risk by damaging tissue and DNA in genes. Ionizing radiation comes from x-ray machines, cosmic particles from outer space and radioactive elements. Radioactive elements emit ionizing radiation as their atoms undergo radioactive decay.
Radioactive decay is the emission of energy in the form of ionizing radiationHelpionizing radiationRadiation with so much energy it can knock electrons out of atoms. Ionizing radiation can affect the atoms in living things, so it poses a health risk by damaging tissue and DNA in genes.. The ionizing radiation that is emitted can include alpha particles, beta particles and/or gamma raysHelpgamma raysA form of ionizing radiation that is made up of weightless packets of energy called photons. Gamma rays can pass completely through the human body; as they pass through, they can cause damage to tissue and DNA.. Radioactive decay occurs in unstable atoms called radionuclides.
Explanation:
What effect does pressure have on a gas in a
closed container?
Answer:
La presión de un gas en un recipiente cerrado es inversamente proporcional al volumen del recipiente, cuando la temperatura es constante.LÑÑ
Explanation:
El volumen es inversamente proporcional a la presión: Si la presión aumenta, el volumen disminuye. Si la presión disminuye, el volumen aumenta.
What is the formula Trisilicon tetra nitride
SHOW ALL WORK! Partial
How many words can Jamie type in 2 days if she can type 62 words per minute?
1 day = 1440 minutes
2 days = 2880 minutes
2 days = 62 words per minute× 2880 minutes
2 days = 178560 words
Therefore she can type 178560 words in 2 days if she can type at 62 words per minutes
CO, + H2O –H^2 CO^3 The reaction is which type of chemical reaction?
Answer:
Combination reaction or synthesis reaction
Explanation:
Given reaction:
CO + H₂O → H₂CO₃
The type of reaction shown above is a combination or synthesis reaction. A combination reaction is one in which a single product is formed from two or more reactants.
In the given reaction carbon monoxide combines with water to produce hydrogen carbonate.
The formation of compounds from the union of their constituent elements falls into this category of reactions.
How can you tell the difference between a balanced equation or unbalanced equation?
Answer:
By counting the number of atomic number
3. A student measured 15.0 grams of ice in a beaker. The beaker was then
placed on a hot plate where it was heated uniformly for a certain amount
of time. During the melting process of the ice, the student noted that the
temperature was at O degree Celsius. When all the ice converted to water,
the final temperature was also at 0 degree Celsius. How much heat was
used to melt the ice?
Please help me !
Answer:
The heat that was used to melt the 15.0 grams of ice at 0°C is 4,950 Joules
Explanation:
The mass of ice in the beaker = 15.0 grams
The initial temperature of the ice = 0°C
The final temperature of the ice = 0°C
The latent heat of fusion of ice = 330 J/g
The heat required to melt a given mass of ice = The mass of the ice to be melted × The latent heat of fusion of ice
Therefore, the heat, Q, required to melt 15.0 g of ice = 15.0 g × 330 J/g = 4,950 J
The heat that was used to melt the 15.0 grams of ice = 4,950 Joules.
List two examples of items that undergo sublimation
Answer:
Examples of solids that sublime are dry ice (solid carbon dioxide), iodine, arsenic, and naphthalene (the stuff mothballs are made of).
Explanation:
pleasee helpppp
i have posted this many times m=but no one has helped :(
will mark brainliest!! :)
Answer:
its 1 transferd electrons 2 shared electrons 3 metal only
Explanation:
Answer:
1 transferd electrons 2 shared electrons 3 metal only
Explanation:
What mass of copper sulphate dissolves in 100g of water at 70 °C
The answer mass of copper sulphate is
46g
Electrical cords are made up of two layers. The wire inside is made of metal. This is surrounded by a cover made of plastic or rubber. How do the wire and cover compare in their ability to conduct or insulate electricity? A. The wire is a conductor, and the cover is an insulator. B. The wire is an insulator, and the cover is a conductor. C. Both the wire and the cover are insulators. D. Both the wire and the cover are conductors.
Answer:
A
Explanation:
The correct answer would be that the wire is a conductor and the cover is an insulator.
The wire inside an electrical cord is made up of metals and metals are generally considered to be good conductors of heat and electricity. The cover which is made of plastic or rubber, however, are known to be poor conductor of electricity. Hence, the wire are considered to be conductors of electricity while the rubber covers act as insulators to protect users from getting electrocuted.
The correct option is A.
A molecular formula shows the arrangement of the atoms in a molecule. True or False?
Answer:
The answer is true
Explanation:
Physical weathering caused by the action of freezing water
Answer:
Frost action involves the ~weathering~ processes caused by repeated cycles of freezing and thawing.
Explanation:
Answer: Physical weathering is caused by the effects of changing temperature on rocks, causing the rock to break apart. The process is sometimes assisted by water. Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.
Explanation:
what deterilnines whether or not an atom is boron
Answer:
Has 5 protons and the atomic number is 5.
Explanation:
The atomic number is equal to the number of protons and every element has a different number of protons. Therefore, finding how many protons there are and comparing to atomic numbers (or vice versa) would allow you to find if the atom is boron.
what is the electron configuration for a neutral atom with five valence electrons
Answer:
pee
Explanation:
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Can a stable compound be made from lithium and oxygen
Answer:
No, because oxygen wants two electrons to become stable and lithium will only give up 1 electron.
can anyone tell me what the +1 in a nuclear symbol stands for?
The chemical equilibrium is given:
2NO (g) + O2(g) <—>2N O2, (g)
In a container of volume 10L is in equilibrium a mixture consisting of 10 mol NO (g), 10 mol O2, (g) and 20 mol NO2, (g).
The volume of the container changes under constant temperature and after the restoration of equilibrium the amount of NO has increased by 25%. Calculate the volume change in L.
How do I find the change in volume?
P.s sorry if my English isn’t perfect.
The volume of NO₂=6.25 L
Further explanationAvogadro's stated :
In the same T,P and V, the gas contains the same number of molecules
So the ratio of gas volume = the ratio of gas moles
[tex]\tt \dfrac{V_1}{V_2}=\dfrac{n_1}{n_2}[/tex]
the volume of each gas (in a container of volume 10L) :
Total mol=10+10+20=40 mol
NO :[tex]\tt \dfrac{10}{40}\times 10=2.5~L[/tex]
O₂ :[tex]\tt \dfrac{10}{40}\times 10=2.5~L[/tex]
NO₂ :[tex]\tt \dfrac{20}{40}\times 10=5~L[/tex]
NO₂ (has increased by 25%) :
[tex]\tt 0.25\times 5~L=1.25\\\\new~volume=5+1.25=6.25[/tex]
O₂ :[tex]\tt \dfrac{10}{20}\times 6.25=3.125[/tex]
NO :[tex]\tt \dfrac{10}{20}\times 6.25=3.125[/tex]
How do solar panels create an electric force field and generate an electric current?
Answer:
Sunlight hits the solar panels, and creates an electric field. The electricity generated flows to the edge of the panel, and into a conductive wire. The conductive wire brings the electricity to the inverter, where it is transformed from DC electricity to AC, which is used to power buildings.
Answer:
Sunlight hits the solar panels, and creates an electric field. The electricity generated flows to the edge of the panel, and into a conductive wire. The conductive wire brings the electricity to the inverter, where it is transformed from DC electricity to AC, which is used to power buildings.
Explanation:
hope this help
brainliest please!!!!
can Fossil Fuels harm?
Burning fossil fuels emits a number of air pollutants that are harmful to both the environment and public health. Sulfur dioxide (SO2) emissions, primarily the result of burning coal, contribute to acid rain and the formation of harmful particulate matter.
Answer:
No
Explanation:
Because they helps us to make oil and is not harmful to us
what is at the anode and cathode for Silver carbonate(Ag2CO3)
Answer:
bla bla bla bla hahahhaa jokers
PLEASE HELP! THIS IS A TIMED QUIZ!!!
Which category do you think this mystery solar system object fits best in?
Made of: Spherical gas
Size: 12x as big as Earth
Orbit time: 152 years
A. Outer Planet
B. Inner Planet
C. Asteroid
D. Dwarf Planet in Kuiper Belt
Answer:
This is an outer planet!
Question 8 helpppppp
Answer:
Explanation:
This is lechatlier's principle, which basically talks about how adding or taking away things will disrupt equilibrium and the system will act a certain way to restore equilibrium
1. adding NH3 causes the equilibrium to shift left - produce more reactants
2. removing N2 causes the equilibrium to shift left - produce more reactants
3. same as number 2
4. decreasing pressure causes equilbrium to shift to the side with more moles so it shifts left and produces more reactants
5. catalyst doesn't change anything about equlibrium, it only affects the reaction's rate
Le Chatelier's principle is a principle which predicts the effect of change in condition on a the position of a equilibrium.
Change could be in Temperature, Moles(Concentration), Pressure.
-------------------------------------------------------------------------------------------------------------
EFFECTS ON EQUILIBRIUM__________________________________________________Temperature:We could change the temperature by increasing or decreasing it, and there are two types of reactions, endothermic or exothermic, both have different outcomes by changing the condition.
__________________________________________________________
In Endothermic,
When we increase the temperature, It will favor the formation of product thus MORE PRODUCT will be formed - equilibrium will shift towards right i.e. product side.
When we decrease the temperature, It will favor the formation of reactants thus MORE reactant will be formed - equilibrium will shift towards left i.e. reactants side.
__________________________________________________________
In Exothermic,
When we increase the temperature, It will favor the formation of reactants thus MORE REACTANT will be formed - equilibrium will shift towards left i.e. reactants side.
When we decrease the temperature, It will favor the formation of product thus MORE PRODUCT will be formed - equilibrium will shift towards the right i.e. product side
_____________________________________Pressure:When we increase the pressure, The equilibrium shifts towards the fewer moles of a gas. Wherever there are less moles, it could be any, reactant or product, the increase of Pressure will favor in formation of them.
When we decrease the pressure, The equilibrium shifts towards the more moles of a gas. So whether reactants or product have the higher moles, the decrease in pressure will favor in the formation of them.
_____________________________________Concentration of moles:When we increase the concentration of moles of any substance, The equilibrium will shift away from that substance. So if we want to make more product and there are more moles of reactant present, then Increase the concentration of reactants.
When we decrease the concentration of any substance, The equilibrium will shift towards that substance. So if we want to make more product, decrease its concentration or add more reactant.
_____________________________________Catalyst:By the use of the catalyst, There is no effect on the equilibrium. The rate of both forward and backward reaction are increased with the equal amount.
_____________________________________Question:By keeping that in mind,
A) Extra [tex]NH_{3}[/tex] will shift the equilibrium towards left i.e. more reactants will be formed.
B) Extra N2 is removed, the equilibrium will shift towards the left i.e. more reactants will be formed.
C) N2 is added, the equilibrium will shift towards right i.e. more PRODUCT will be formed. (I assumed there was a typing error and it meant Addition instead of removal)
D) When we decrease the pressure the equilibrium will shift towards the left i.e. more reactant will be formed.
E) Catalyst has no effect on the system
_____________________________________Best Regards'Borz'If a decrease in temperature accompanies a reaction, what occurred?
Energy was released.
Energy was destroyed.
Energy was created.
Energy was absorbed.
Surely, when there is a decrease in temperature accompanying a chemical reaction, this indicates that: energy was absorbed.
The correct answer choice is option d.
How energy is absorbed by decreasing temperature in a chemical reaction.In happens that in a chemical reaction which leads to the absorption of energy due to decrease in temperature, this results as a result of the fact that bonds in the reactants of the reaction are broken than it is released
So therefore, we can now deduce and confirm from the explanation given above that it is an endothermic reaction when energy is absorbed by the system.
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Find the mass of AlCl3 that is produced when 3.58 moles of Al2O3 react with excess HCl according to the following equation.
Al2O3(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2O(l)
Moles of Al2O3, m = 3.58 moles.
We need to find the mass of AlCl3 produced.
Solution :
1 mole of Al2O3 produce 2 moles of AlCl3.
So, 3.58 moles of AlCl3 produce 7.16 moles of AlCl3.
Mass of AlCl3 produced is :
m = moles × molecular mass of AlCl3
m = 7.16 × 133.34 g
m = 954.714 g
Therefore, mass of AlCl3 produced is 954.714 g.
Hence, this is the required solution.
A 10.3 L cylinder contains 10.67 moles of Cl2 at 21.2 C. What is the pressure (atm)
Answer:
Explanation:
we know that ideal gas equation is
PV=nRT
P=nRT/V
V=10.3L
n=10.67
T=21.2+273=294
R=0.0821
P=10.67*0.0821*294/10.3
P=25.00atm
Answer:
P = 25.0 atm
Explanation:
Given data:
Volume of gas = 10.3 L
Number of moles of Cl₂ = 10.67 mol
Temperature = 21.2 °C
Pressure of gas = ?
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
Now we will convert the temperature.
21.2+273 = 294.2 K
10.3 L × P = 10.67 mol × 0.0821 atm.L/ mol.K × 294.2 K
P = 257.72 atm.L / 10.3 L
P = 25.0 atm
Name one star from the diagram that is fusing hydrogen into helium
Which situation demonstrates dormancy?
A plant germinates in the spring.
A plant grows leafs laterally.
A plant closes its flowers at night.
A plant becomes inactive and stops growing.
Answer:
Your answer is D
Explanation: Have a nice day or night
(❁´◡`❁)
Answer:
A plant becomes inactive and stops growing!!!
(aka D)
I got it right if you got it right leave a like
Explanation:
Give a scenario in which a good conductor in heat would come in handy.