3.0 x 108 m/s is the
Answer:
Speed of light
Explanation:
The value 3.0 x 10⁸m/s is taken as the speed of light.
It is a constant.
It implies that light travels a distance of 3 x 10⁸ in just one second. This value is for the speed of light in a vacuum when there are not particles obstructing its movement. The speed of electromagnetic radiations in free space is also taken as the speed of light.The half life of radium-226 is 1600 years.
a. After how many half-lives would 25% of the radium-226 remain.
b. Write a function m(t) that models the mass remaining after years.
c. How much of the sample will remain after 3000 years?
d. After how long will only 15 mg of the sample remain?
Answer:
Explanation:
a )
half life = 1600 years
50% in 1600 years
25% in next 1600 years
so 25% in total of 3200 years .
b )
disintegration constant = .693 / half life
= .693 / 1600
λ= 4.33 x 10⁻⁴ year⁻¹
m(t) = [tex]m_0e^{-\lambda t }[/tex]
m₀ is initial mass , λ = 4.33 x 10⁻⁴ year⁻¹
c )
m(t) after 3000 years , t = 3000
m(t) = [tex]m_0e^{-4.33\times10^{-4 }\times 3000 }[/tex]
= [tex]m_0e^{-1.3}[/tex]
= .2725 m₀
percentage of mass remaining = 27.25 %
25% radium-226 remain after 3200 years. 6.82 mg of sample remains after 3000 years. 15 mg of the sample will stay long about 1179. 19 years.
Half life of radium-226 = 1600 years
What is half-life?
half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay.
Calculation of each part can be done as
a )
half-life = 1600 years
50% in 1600 years
25% in next 1600 years
so 25% in total of 3200 years .
b )
Let decay function is
[tex]m(t) = m_o e^{-kt} \ \ \ \ \ ...(i)\\[/tex]
where k is decay constant
At half life,
[tex]m(t) = \frac{m_o}{2},t= 1600\ years\\So,\ \frac{m_o}{2} = m_oe^{-k1600}\\\frac{1}{2} = e^{-k1600}\\[/tex]
applying log on both sides
[tex]ln \frac{1}{2} = lne^{-1600k}\\-0.693147 = -1600 k \\k =\frac {0.693147}{1600}\\k = 4.332\times10^{-4}\\[/tex]
substitute the value of k in equation (i)
[tex]m(t) = m_oe^{-4.332\times10^{-4t}}\\m(t) = 25e^{-0.0004332t}[/tex]
c) when t = 3000 years
[tex]m(t) = 25e^{-0.0004332t}[/tex]
[tex]m(3000) = 25e^{-0.0004332\times3000}[/tex]
remain sample after 3000 years = 6.82 mg
d) when m(t) = 15 mg
[tex]15 = 25e^{-0.0004332t}\\e^{-0.0004332 t} = \frac{15}{25}\\applying\ log\ on\ both\ side\\ln \ e^{-0.0004332t}=ln(\frac{15}{25)}\\-0.0004332t = -0.510825\\t=\frac{0.510825}{0.0004332}\\t= 1179.19 \ years[/tex]
Hence, this is the required answer.
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Consider the following equilibrium.
NH3(aq) + H2O(l) equilibrium reaction arrow NH4+(aq) + OH −(aq)
What will happen to the equilibrium constant if the concentration of OH − increases through the addition of a small amount of NaOH(aq)?
Answer:
It will remain the same
Explanation:
The equilibrium constant of the reaction will remain the same if the concentration of the OH is increased.
Changes in concentration values of any of the reactant does not affect the value of the equilibrium constant.
The equilibrium constant is a constant at a given temperature. It is temperature dependent. Since we have no change in temperature, therefore, the equilibrium constant will not change.The equilibrium constant if the concentration of OH − increases through the addition of a small amount of NaOH(aq) is :
- Remains same.
Equilibrium ReactionThe equilibrium constant of the response will stay the same in case the concentration of the OH is increased.
Changes in concentration values of any of the reactant does not influence the esteem of the equilibrium constant.
The equilibrium constant may be a consistent at a given temperature.
It is temperature dependent. Since we have no alter in temperature.Learn more about "Equilibrium":
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Scientists discover remains of wooden structures near a Celtic runes site. What kind of testing will indicate when the stones were moved into place by the Celts?
Carbon dating
Radioactive dating
Answer:
Carbon
Explanation:
Bc i got this question on my test
Answer:
A. Carbon dating
Explanation:
I took the test proof
Which problem that the most scientists believe is partly caused by carbon dioxide?
Answer:
Climate change
Explanation:
Climate change is primarily a problem of too much carbon dioxide (CO2) in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests
Is steel wool and vinegar an exothermic reaction? Explain.
Answer:
Vinegar contains acetic acid which removes this coating. When the protective coating is removed, oxygen in the atmosphere can reach the iron in the steel wool and a chemical reaction called oxidation occurs. ... This reaction is also an exothermic reaction. It creates heat energy
Explanation:
hope this helps u
Vinegar incorporates acetic acid which gets rid of this coating. When the defensive coating is removed, oxygen in the environment can reach the iron in the metal wool and a chemical reaction called oxidation occurs. This reaction is additionally an exothermic reaction. It creates warmth energy.
Hope it helped! Have a nice day! <3
How do you determine whether an acid should be broken up into ions in the
complete ionic equation?
Answer:
When chemicals in solution react, the proper way of writing the chemical formulas of the dissolved ionic compounds is in terms of the dissociated ions, not the complete ionic formula. A complete ionic equation is a chemical equation in which the dissolved ionic compounds are written as separated ions.
When sodium atoms (Na) and chlorine atoms (CI) join to make
Answer: Potassium and fluorine
Explanation:
The two rows form bonds the easiest
Answer: #1
Explanation:
Calculate the number of C atoms in 0.716 mole of C?
Answer:
The answer is 4.31 × 10²³ C atoms
Explanation:
The number of C atoms can be found by using the formula
N = n × Lwhere 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
N = 0.716 × 6.02 × 10²³
We have the final answer as
4.31 × 10²³ C atomsHope this helps you
pls help!!
The number that represents a neutral pH is ________.
Answer:
7
Explanation:
which of the following is an example of
a physical property?
Answer:
physical property is property that you can touch, smell as it is bumpy it smells like eggs.
Explanation:
YW
Answer:
Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.
Explanation:
how many moles of nitroge are there in 50.0 g of nitrogen?
1.785714286 moles
The number of moles (n) for nitrogen is: [ n=50.0÷28.0 ] = 1.785714286 moles.
Calculate the mass percentage of NaClNaCl in a solution containing 1.50 gg of NaClNaCl in 50.0 gg of water.
Answer:
%m/m = 2.9 %
Explanation:
The mass percentage (m/m %) of a solution is calculated as follows:
m/m % = mass of solute/ mass of solution x 100
The solution is composed by : solute + solvent. In this case, the solute is NaCl and the solvent is water. We have:
mass of solute = 1.50 g
mass of solvent = 50.0 g
mass of solution = mass of solute + mass of solvent = 1.50 g = 50.0 g = 51.5 g
Thus, the mass percentage of NaCl in the solution is :
% m/m = (1.50 g)/(51.5 g) x 100 = 2.91 % ≅ 2.9 %
what do y'all girls find attractive on a guy?
Answer:
alot of things
Explanation:
The Venmo diagram compares protons with electrons. Which shared property belongs in the region marked B?
Mineral reaction to stress
Answer:
Tenacity describes the reaction of a mineral to stress such as crushing, bending, breaking, or tearing. ... The majority of all minerals are brittle. An example is Quartz. (Minerals that are not brittle may be referred to as Nonbrittle minerals.)
A very new item just arrived in the market. It is very good for construction, and other things. Now, this item has chemicals, and in every drop, there are 400 grams of NaCI. If there are 10 drops in this item, how many grams of NaCI are in one bottle?
Answer: 4,000 grams of NaCI
Explanation:
We know that there are 400g of NaCI in one drop.
This bottle has 10 drops of this item.
So, we have to multiply the amount of NaCI in a drop by the amount of drops.
400 x 10 = 4,000.
The answer to the question is 4,000. Hope this helps!
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Nose color is an inherited trait in dogs. Two puppies from the same set of parents have different color noses. One puppy has a pink nose and one puppy has a black nose. How can puppies from the same set of parents have different color noses?
A.
The pink-nosed puppy and the black nosed puppy must not actually be related.
B.
The pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents.
C.
The pink-nosed puppy has a different number of chromosomes than the black nosed puppy.
D.
The pink nosed puppy and the black nosed puppy have different chromosomes for the two nose colors.
Answer:
I thin its B im not sure though
Explanation:
The puppies from the same set of parents have different color noses because the pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents. Thus, the correct option is B.
What is a gene?A gene is the unit of inheritance which is made up of DNA (deoxyribonucleic acid). Every person receives two copies or alleles of each gene which is inherited from each of the two parent.
Genes are made up of DNA, so each of the chromosome contains many different genes. Genes carry the information which determines the traits or characteristics that are passed on to their offspring or inherited from the parents.
The puppies from the same set of parents have different colored noses because pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents.
Therefore, the correct option is B.
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What is the pH value of distilled water?
Answer:
7
Explanation:
Which best describs the energy transformation in a battery powered flash light ?
a
Chemical, to electrical, to thermal, to radiant
b
nuclear, to electrical, to thermal, to radiant
c
Mechanical, to electrical, to Thermal, to radiant
d
Chemical, to electrical, to mechanical, to radiant
Answer:
I think it's C
Explanation:
Sorry if its wrong
Answer:
C
Explanation:
Calculate the percent composition by mass of each element in Al(OH)3.Al(OH)3. Use at least three significant figures.
Answer:
Explanation:
Al(OH)₃
Total molecular weight = 27 + 3 x ( 16+1)
= 78
Al = 27
% of Al = 27 x 100 / 78 = 34.61%
O = 48
% of O = 48 x 100 / 78 = 61.55 %
H = 3
% of H = 3 x 100 / 78
= 3.84%
Al = 34.61%.
O = 61.55%.
H = 3.84%.
Which statement accurate describes plate tectonics?
Answer:
the lithosphere is broken into sections called plates.
Answer:
The lithosphere is broken into sections called plates.
Explanation:
edge2020
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8. Which object has molecules that are moving? water in a cup that is not moving, or water in the ocean
PLEASE HELP ASAP!!!
Answer:
Water in the ocean
Explanation:
The water in the ocean is always moving so all the molecules are was well
A gas expands from 285 mL to 789 mL at constant temperature. How much work is done by the gas (joules) if it expands against a constant pressure of 6.00 atm?
Answer:
-306j
Explanation:
For this question we define an equation:
W = -Pext(Vj-Vi)-----> eqn 1
P = 6atm
Vi = 285 ml
We convert it to litre
= 285/1000 mL
= 0.285 L
Vj = 789 mL
When converted to litre
= 789/1000 mL
= 0.789 L
These values are all going to be put values in the eqn 2 above
W = -Pext(Vj-Vi)
W = -6.0x (0.789L - 0.285L)
W = -3.024
W = -3.024 x 101.33 J
This gives us the answer
W = -306 J
Thank you!
Answer: -306 J
Europium orbital diagram
. Calculate the pH, pOH, Ka, Kb, pKa, and pKb for a 0.082M solution of triethylamine?
Answer:
pH = 4.40
Explanation:
i need help ):
soo.. help me ! please (:
Answer:
23 Sandwiches
6 slices of bread
0 slices of cheese
Explanation:
brainliest pls:)
SO3 is a covalent compound with no lone pairs on the central S atom. What's the structure of a molecule of SO3? Is an SO3 molecule polar or non-polar?
Question 14 options:
A)
Trigonal planar, non-polar
B)
Trigonal pyramidal, polar
C)
Trigonal planar, polar
D)
Trigonal pyramidal, non-polar
Answer:
A
Explanation:
it has non polar molecule, because it has the equal sharing of electrons, so equal repulsion from all sides. atoms are equally represented.
Answer:
Trigonal planar, non-polar
Explanation: