Answer: The half life of the sample is 60.26 years.
Explanation:
All radioactive decay reactions follow first order reaction.
The formula used to calculate the rate constant for a first order reaction follows:
[tex]k=\frac{2.303}{t}\log \frac{a}{(a-x)}[/tex]
where,
k = rate constant = ?
t = time period = 25 years
a = initial concentration of the reactant = 500 g
a - x = concentration of reactant left after time 't' = (500 - 125) = 375 g
Putting values in above equation, we get:
[tex]k=\frac{2.303}{25yrs}\log \frac{500g}{375g}\\\\k=0.0115yr^{-1}[/tex]
Now, to calculate the half life period of the reaction, we use the equation:
[tex]t_{1/2}=\frac{0.693}{k}[/tex]
where,
[tex]t_{1/2}[/tex] = half life period of the reaction = ?
k = rate constant = [tex]0.0115yr^{-1}[/tex]
Putting values in above equation, we get:
[tex]t_{1/2}=\frac{0.693}{0.0115yr^{-1}}\\\\t_{1/2}=60.26yrs[/tex]
Hence, the half life of the sample is 60.26 years.
what is the number of oxyegen on periodic table?
Answer:
16
Explanation:
Answer:
Oxygen has an atomic number of 8
Explanation:
Iodine is 80% 127I, 17% 126I, and 3% 128I. Calculate the average atomic mass of Iodine.
Given
80% 127I, 17% 126I, and 3% 128I.
Required
The average atomic mass
Solution
The elements in nature have several types of isotopes
Atomic mass is the average atomic mass of all its isotopes
Mass atom X = mass isotope 1 . % + mass isotope 2.% + ... mass isotope n.%
Atomic mass of Iodine = 0.8 x 127 + 0.17 x 126 + 0.03 x 128
Atomic mass of Iodine = 101.6 + 21.42 + 3.84
Atomic mass of Iodine = 126.86 amu
110 A common liquid contains 11.19% hydrogen
and 88.81% oxygen by mass.
a) Calculate the number of moles of hydro-
gen atoms and oxygen atoms in 100.0 g of
this liquid.
Explanation:
number of moles =[tex] \frac{given \: mass}{molar \: mass} [/tex]
thus, number of moles of hydrogen= 11.91/1=> 11.91number of moles of oxygen= 88.81/32 = 2.77=> 2.77hope it helps:)
If the quantity of heat lost or gained is ( ΔH = mass X change in T X specific heat) mass change in T specific heat, what is the amount of heat required to raise 200.0 g of water from 22.00°C to 100.0°C?
Specific heat of water is 4.180 J/g °C
Liquids are not easily compressible but flow easily.
O True
O False
difference between NaOH and HCI
Answer:
hcl:-is as strong acid than water.naoh:-is as strong base than Nh3
Explanation:
hence naoh is base and HCl is acid
Which type of galaxy forms when two other galaxies crash into each other? They are small galaxies made up of bright, young stars.
Answer:
elliptical galaxy
Explanation
:The combination of the two galaxies then forms what appears to be an elliptical galaxy as the arms begin to disappear. The merger of gasses creates new stars, and the new shape becomes more elliptical, globular, or sometimes irregular.
A sample of unknown element X contains the following isotopes: 80% of C -64, 15% of X - 65, and 5% of X-66. What is the average atomic mass of element X? Can somebody help me with this question. Will mark brainliest.
Answer:
64.25
Explanation:
Average atomic mass = percentage × mass of all isotopes/ 100
Relative atomic mass = 80*64+15*65+5*66/100
=5120+975+330/100
=6425/100
64.25
A gas occupies 2.5 L at 2.5 atm. What is the volume if the pressure changes to 1.5 atm?
Answer:
p1v1=p2v2
2.5×2.5=1.5×v2
6.25=1.5v2
6.25 /1.5=v2
4.16L=v2
How many molecules are in 200.0 g of ammonium sulfide
Answer: 1.51355 mol.
Explanation:
The provided balanced equation applies to the reaction that takes place between zinc metal and copper(I) nitrate.
Zn +2 CuNO3 - Zn(NO3)2 + 2 Cu
If the reaction begins with 0.037 moles of zinc and 0.11 moles of copper(I) nitrate, how many grams of copper metal can be produced? Assume 100%
yield. Round off your answer to the nearest tenth of a gram. Record your answer in the grid.
Here ^ you have to tap to see the full pic. comment if u dont understand anything :)
Mass of copper produced = 5 g
The balanced chemical equation:
Zn + 2CuNO₃ → Zn(NO₃)₂ + 2Cu
Given:
0.037 moles of zinc and 0.11 moles of copper(I) nitrate
To find:
Mass of Cu metal produced=?
The amount of CuNO₃ produced =0.11/2=0.055moles
Thus, amount of copper=0.037*2= 0.0740 moles
The mass of copper produced =0.0740*63.5=4.699g=5g
Therefore, the Mass of Cu produced will be 5 g.
Learn more:
brainly.com/question/13852350
why does the moon appear to be so bright in the sky
Answer:
The shine of the Sun on the lunar surface brightens it, while also giving the moon "dark sides". Its position in Earth orbit allows it to have certain phases because of its orbital position relative to the sun. You're welcome.
Explanation:
What is one property of salts?
Answer:
They are neutral
Explanation:
Salts are chemical compounds formed when acids and a bases are combined together. Both substances nuetralize each other as they react, thereby forming salts which are neutral substances. This resultant compounds are neither basic nor acidic. They have a pH of 7, which makes them neutral in nature.
Calculate the percentage by mass of oxygen in Al2(SO4)3 (Al=27, S=32,O= 16) PLEASE SHOW FULL WORKING
Answer:
There is 61.538% oxygen in Al2(SO4)3.
Explanation:
Wt Of oxygen in the compound = 12*16 = 192 amu.
Total Wt. Of the compound = 2*12+3*32+12*16 = 312 amu.
Thus, percent of oxygen = Wt of oxygen/total Wt. Of compound *100
= 192/312 * 100=61.538 %
what is the relative formula mass of butane?
Answer:
The molecular formula of butane is C4H10. Calculate its molar mass.58.1 g/mole 14. is answer.
Explanation:
I hope it's helpful!
A chemical reaction is a process in which what
Products produced reactants
The law of conservation of mass applies
Combustion always occurs
None of the above
the law of conservation of mass applies.....?
Short description about health science
Answer:
Both traditional Western and alternative medicine can be considered health sciences. ... The field includes the study of medicine, nutrition and other health-related issues and the affect they may have on both humans and animals.
Explanation:
Which of the following would be an example of applied science?
Investigating how carbon dioxide levels impact ocean pH
Investigating why water expands when it freezes
Investigating the conductivity of metalloids
Investigating how to develop a more efficient solar panel
Answer:
Investigating how carbon dioxide levels impact ocean pH
Explanation:
I hope this helps! :)
Pls help me plsssss my mom is coming home soon I’ll mark brainliest hurrrrrrrrry
Answer:
Its A, sorry I wrote something else.
Explanation:
The equator is the warmest, and the sunlight is not pointing towards point A.\
Friendly guy that likes to help
Using the reaction below determine the amount of Sulfur proceduced in grams (this is a limiting reaction question) 2 H2S + SO2 -> 3 S + H2O 3.26g of dihydrogen sulfide react with 4.42 g of sulfur dioxide
Answer:
= 2.2 g pf S. produced
Explanation:
Balanced Reaction equation:
[tex]2H_{2} S + SO_{2}[/tex] → [tex]3S + 2H_{2} O[/tex]
1 mole of H2S - 34.1g
? moles - 3.2g
= 3.2/34.1 = 0.09 moles of H2S
Also,
1 mole of S02 - 64.07 g
? moles - 4.42g
= 4.42/64.07 = 0.069 moles of SO2
Meaning SO2 is the limiting reagent
Finally, 3 moles of S - 32g of sulphur
0.069 mole = ? g of Sulphur
= 0.069 x 32
= 2.2 g pf S.
how many moles are in 3.00x 10^22 atoms of He?
Answer:
0.05 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{3.0 \times {10}^{22} }{6.02 \times {10}^{23} } \\ = 0.049833...[/tex]
We have the final answer as
0.05 molesHope this helps you
_____are chains of amino acids
lipids
carbs
proteins
nucleic acids
Answer: proteins
Explanation:
Which term describes this reaction?
addition
condensation
elimination
substitution
Addition is the answer
Benjamina started her walk from the front door of her ground floor apartment.She walked 6 meters to the corner of the building and then turned the corner and walked 10 meters to her friends apartment.Identify the difference between the distance she walked and her displacement.
Answer:
See explanation
Explanation:
The major difference between distance and displacement is that distance is a scalar quantity while displacement is a vector quantity. Scalar quantities have magnitude without direction while vector quantities have both magnitude and direction.
The distance covered by Benjamina in both cases just refer to the difference in her position at each time without reference to the direction in which she changed her position.
Her displacement will clearly mention the direction in which she moved both when she walked to the front door of her apartment and when she walked to a friend's apartment.
What products are always made when any carbon-based fuel
is burned in the presence of oxygen?
a) carbon dioxide and hydrogen
b) carbon dioxide and water
c) oxygen and carbon dioxide
d) oxygen and water
Answer:
B) carbon dioxide and water
Answer: B.) carbon dioxide and water
Explanation:
bc I got it right?
Which evidence shows that heat is given off when a candle burns?
A. A match is used to light the candle.
B. The burning candle produces a yellow flame.
O c. Covering the burning candle extinguishes the flame.
D. Solid candle wax near the flame melts as the candle burns.
thing
Answer:
D. solid candle wax near the flame melts as the candle burns.
Answer:
Part D, melting is a product of heating
Explanation:
Rewrite and Balance the Equation
N₂ + H₂ -> NH3
Answer:N
2
+ 3
H
2
-----> 2N
H
3
Explanation:
N
2
+
H
2
-----> N
H
3
Let us balance this equation by counting the number of atoms on both sides of the arrow.
N
2
+
H
2
-----> N
H
3
N=2 , H=2 N=1, H=3
To balance the number of N atom on Right Hand Side (RHS) , I will add one molecule of N
H
3
on RHS
N
2
+
H
2
-----> 2N
H
3
N=2 , H=2 N=2 , H= 6
To balance the number of H atoms on Left Hand Side (LHS) , I will add two molecules of
H
2
on LHS
N
2
+ 3
H
2
-----> 2N
H
3
N=2 , H=6 N=2 , H= 6
Answer link
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How can I balance this equation? ___ AlBr3 + ____ K2SO4 ---> ____ KBr + ____ Al2(SO4)3
How can I balance this equation? ____ Pb(OH)2 + ____ HCl ---> ____ H2O + ____ PbCl2
Answer:
you said brainliest
Explanation:
As an electron in an atom moves from a higher energy state to a lower energy state, the atom
1 becomes a negative ion
2 becomes a positive ion
3 releases energy
4 absorbs energy
Answer:
3 releases energy
Explanation:
An electron in an energy level has a definite amount of energy associated with it at that level.
Electrons can undergo transitions from one level to another. However, when the electron changes its state, it must absorb or emit the exact amount of energy which will bring it from the initial to the final state.
When the electron is excited, it moves from the ground state to an excited state, it must absorb energy. On returning from an excited state to a lower level or the ground state, energy is emitted, giving rise to a line in the spectrum.
Answer: 3 because it releases energy
Energy has different _____ , such as electrical, chemical, and thermal.
Answer:
forms/types
Explanation:
Spring and autumn both have a certain day where the amount of daytime hours
and nighttime hours are the same. What is this day called?
a. Equator
b. Equilibrium
c. Equality
d. Equinox
Answer:
d. Equinox
Explanation:
A certain day in spring and autumn where the amount of daytime hours and nighttime hours are the same is called equinox.
Equinox occurs twice in a year on March 20 and September 23rd.
During an equinox, the south and north hemisphere of the earth are receiving equal amount of sunlight. The opposite of equinox is solstice in which the duration of light is unequal. The equator is the only great circle that is a line of latitude.