Answer:
The material is 30 years old.
Explanation:
The decay of radioactive isotopes can be modelled by the following ordinary differential equation:
[tex]\frac{dm}{dt} = -\frac{m(t)}{\tau}[/tex] (Eq. 1)
Where:
[tex]m(t)[/tex] - Current mass of the isotope, measured in grams.
[tex]\tau[/tex] - Time constant, measured in years.
[tex]\frac{dm}{dt}[/tex] - Rate of change of the isotope in time, measured in grams per year.
After some handling, we find that the solution of the differential equation is:
[tex]\frac{m(t)}{m_{o}} = e^{-\frac{t}{\tau} }[/tex] (Eq. 2)
Where:
[tex]m_{o}[/tex] - Initial mass of the isotope, measured in grams.
[tex]t[/tex] - Time, measured in years.
Now we clear time within the expression above:
[tex]t = -\tau\cdot \ln \frac{m(t)}{m_{o}}[/tex]
Besides, we determine the time constant in terms of the half-life ([tex]t_{1/2}[/tex]), measured in years:
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)
If we know that [tex]t_{1/2} = 10\,yr[/tex] and [tex]\frac{m(t)}{m_{o}} = 0.125[/tex], then the age of the material is:
[tex]\tau = \frac{10\,yr}{\ln 2}[/tex]
[tex]\tau = 14.427\,yr[/tex]
[tex]t = -(14.427\,yr)\cdot \ln 0.125[/tex]
[tex]t \approx 30\,yr[/tex]
The material is 30 years old.
Which of the following are electromagnetic waves? *
Water waves
Sound waves
Radio waves
Seismic waves
As water is cooled, its density increases until it reaches about
A. 4°C
B. 25°C
C. O'C
D. -2°C
What makes the element oxygen different from the element hydrogen?
Answer: the difference is due to the fact that one water molecule has two hydrogen atoms to one oxygen this means it takes two water molecules (2 H2O) to make one oxygen molecule (02) .At the same time however two molecules of water (2 H20) can make two molecules of hydrogen (2 H20)
Explanation: hope this helped and mark me as brainliest please =)
why do the Noble gases have the highest ionization energies across a period?
Answer:
ionization energy decreases from top to bottom in groups, and increases from left to right across a period. So technically, the noble games have the largest ionization energy.
Explanation:
What do radio waves and microwaves have in common?
Both are at the side of the spectrum that has the lowest frequency.
Both are found next to visible light on the electromagnetic spectrum.
Both are at the side of the spectrum that has the highest radiant energy.
Both are at the side of the spectrum that has the shortest wavelengths.
Answer:
Both are at the side of the spectrum that has the lowest frequency.
Explanation:
i took the test
Answer:
a
Explanation:
In order to change a solid to a liquid or a liquid to a gas, what is needed?
A high boiling point
An increase in thermal energy
A high melting point
A decrease in thermal energy
Hide hint for Question 9
Which of the following describes the energy transformations that occur when a toaster is used to make toast?
Thermal energy is transformed into chemical energy in the toaster, and chemical energy is transformed into thermal energy in the toast.
Electrical energy is transformed into thermal energy in the toaster, and chemical energy is transformed into thermal energy in the toast.
Light energy is transformed into thermal energy in the toaster, and thermal energy is transformed into chemical energy in the toast.
Electrical energy is transformed into thermal energy in the toaster, and thermal energy is transformed into chemical energy in the toast.
Answer:
Thermal energy (B)
Explanation:
just did it
Electrical energy is transformed into thermal energy in the toaster, and chemical energy is transformed into thermal energy in the toast. Hence option b is correct.
What is chemical energy?Chemical energy is defined as chemical substances' potential energy, which is released as they experience chemical reactions and change into other substances. Additionally, it is what binds a substance's molecule's together. The body transforms or changes the chemical energy in food into heat and mechanical motion.
The wire attached to the power source transmits electrical energy to the toaster. The heating element is a part of the toaster. This heating element transforms electrical energy into heat energy, which aids in toast preparation, when it comes into contact with it. Thus, with an electric toaster, electrical energy is converted to heat energy.
Thus, electrical energy is transformed into thermal energy in the toaster, and chemical energy is transformed into thermal energy in the toast. Hence option b is correct.
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Does the model correctly represent the electron dot diagram of magnesium? Why or why not? Check all that apply.
M g with 1 dot above and 1 right.
*{Yes, because the chemical symbol of magnesium is Mg.}
No, because the chemical symbol of magnesium is Mn.
*{Yes, because magnesium has two valence electrons.}
No, because magnesium has seven valence electrons.
No, because both of the dots should be on top of the chemical symbol
Answer 1 and 3
Answer:
1 and 3
Explanation:
Answer: A and B or 1 and 3
Explanation:
Why are the Galápagos Islands such a place of interest to the world
Answer:
Explanation:
Carbon dioxide is formed by the given formula.
C(s)+O2(g)→CO2(g)
Carbon dioxide is
A
a compound of two elements, carbon and oxygen.
B
a mixture of two compounds, carbon and oxygen.
C
a compound of two atoms, carbon and oxygen.
D
an element of two atoms, carbon and oxygen.
Answer:
A
Explanation:
answer this pls thanks
Answer: It is element nitrogen. It has an atomic number of 7 and the valence electron is 5. It needs 3 electrons to complete its octet state. That's why sometimes it has the oxidation number of -3 in ammonia.
Who knows the answer to this please help
As a result of the Law of Conservation of Mass, during a chemical change the mass of the
products are equal to the mass of the:
A. particles
B. elements
C. reactants
D. compounds
Answer:
D. Reactants.
Explanation:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
need help asap!!!!
will mark brainliest!!!
We can verify the properties as follows;
1) Sour taste - Put some soda on your tongue
2) Corrode metals - Put a little soda on a clean metal surface
3) Effect on Litmus paper - Dip a blue litmus paper in soda
4) Electrolysis - Add two electrodes to soda and connect a battery.
Does Soda show acidic properties?Soda, specifically carbonated beverages like cola or soda pop, typically exhibits acidic properties. The acidity of soda is primarily due to the presence of carbonic acid (H₂CO₃), which forms when carbon dioxide gas (CO₂) dissolves in water.
When carbon dioxide is dissolved in water under high pressure, it forms carbonic acid through the following reaction:
CO₂ + H₂O ⇌ H₂CO₃
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Can someone tell me about kinetic, potential, and gravitational energy?
Answer:
the internet can teach you alot about all 3 things
Explanation:
Answer:
if you go on YT and search kinetic, potential, and gravitational energy their will be a bill nye vid that is very informational on the topic at hand!!!
Explanation:
hope this helps!!
scientists studying squirrels in a forest observed that the squirrel population decrease over a period of five years. which statement is the most likely explanation for the decrease in the population?
Answer:
1.An increment of predators
2.unavailability of food resources due to change in climate causing famine
3.Spread of diseases over time that might kill the squirrels
4.An increment of squirrels which caused high competition on food,thus some of them had to migrate
5.Might be fire break out over some time that caused death to some squirrels in the reasoning of the period of time
Can somebody help me with this??!
whats the formula for mass
Answer:
The unit of molar mass is kg/mol. Where, m = mass, v = velocity.
Hope that helps :)
. The model shows Earth in several positions relative to the Sun. In which position is it winter in North America?
Which of these describes a challenge that the engineer of a high-altitude
airplane would need to consider?
A. More fuel is used at higher altitudes.
B. The airplane may succumb to the power of gravity as lift
decreases at higher altitudes.
C. The airplane may need a heat shield for protection from sonic
booms.
O D. The airplane will create more drag at higher altitudes than lower
altitudes.
Answer:
I think its (B)
Explanation:
as when the air thins out at higher elevations, your lift decreases so at some point, the plane cant produce enough lift to overcome gravity.
What is the opposite force to pushing off the ground to jump?
Answer:
Newton's Third Law of Motion states that to every action there is an equal and opposite reaction. When the earth pushes on you to send you into the air after jumping, you also push on the earth with the same force. But forces are different from accelerations. A force F is a push or pull on an object
Explanation:
Answer:
Friction
Explanation:
Friction causes an opposite force
first to answer correctly gets brainleist! (you dont needa hear that vid thingy tahts just for ppl who cant read or need orial commidations or wtv lol)
Answer:
The seasons are a result of the tilt of the earth
In a chemical reaction, what happens to the total number of each type of atom?
A
The total number of each type of atom always stays the same.
B
The total number of each type of atom either increases or decreases.
C
The total number of each type of atom always increases.
D
The total number of each type of atom always decreases.
Answer:
A
Explanation:
The total number of each type of atom always stay the same.
8
Calcium carbonate (limestone) decomposes when heated.
Caco, + CaO + CO2
b) Calculate the volume of carbon dioxide produced if 10 grames were decomposed.
Explanation:
Equation -
CaCO₃ → CaO + CO₂
molecular masses of -
CaCO₃ = 40+12+16×3 = 100 g/mol
CaO = 40+16 = 56 g/mol
CO₂ = 12+16×2 = 44 g/mol
Now,
If 100 g of CaCO₃ is decomposed then it produces 56 g of CaO and 44g of CO₂
Then,
If 1 g of CaCO₃ is decomposed then it produces 56/100g of CaO and 44/100g of CO₂
Now,
Here in question, 10g of CaCO₃ is decomposed
It means, It produces
56/100 × 10 = 56/10 = 5.6 g of CaO and
44/100 × 10 = 44/10 = 4.4 g of CO₂
Now,
we get that 10 g of CaCO₃ on burning produces 4.4 g of CO₂
we need to calculate volume of 4.4 g of CO₂
mole = mass/Gram molecular massThen,
mole = 4.4/44 = 0.1
Now,
volume = mole × 22.4 (in Litres)
= 0.1 × 22.4 = 2.24 L
Hence,
2.24 L of CO₂ will be produced when 10g of CaCO₃ decomposed.
Use the equation below to solve the problem that follows.
2H2 (g) + O2 (g) → 2H2O (g)
When David reacts 13.8 grams of hydrogen gas with excess oxygen, 87.0 grams of water are formed. Calculate his percent yield of water.
Im very loss with this question
Percent yield of water : 70%
Further explanationReaction
2H₂ (g) + O₂ (g) → 2H₂O (g)
mol H₂(MW= 2 g/mol) :
[tex]\tt \dfrac{13.8~g}{2~g/mol}=6.9~mol[/tex]
mol H₂O = mol H₂ = 6.9
mass H₂O(theoretical) :
[tex]\tt 6.9\times 18~g/mol=124.2~g[/tex]
[tex]\tt \%yield=\dfrac{actual}{theoretical}\times 100\%\\\\\%yield=\dfrac{87}{124.2}\times 100\%=70\%[/tex]
Someone answer these please! It’s multiple choice
Answer: Number 1 is titanium.
The one where you calculate a tin block is 13.0cm.
3. Is A) Same Density And Same Chemical Properties.
4. Is also A. Ne
Explanation:
I NEED HELP!!
In a stream, how are particles such as silt, clay, and sand carried?
A. as dissolve load
B. as bed load
C. in suspension
D. in solution
In a stream, how are particles such as silt, clay, and sand carried?
A. particles rubbing together
B. An increase is suspended materials
C. an increase in the dissolve load
D. changes in the stream 's carrying capacity
The path of a stream can vary considerably, depending on the slope of the land and the
A. bedload of the stream
B. amount of rainfall
C. amount of hummus present in the soil
D. Type of material through which the stream flows
The amount of dissolved material that stream water carries is usually expressed in
A. cubic meters per second
B. parts per million
C. cubic feet per minute
D. grams per 1000 gallons
The carrying capacity of a stream depends on both the velocity and the
A. Temperature of the water
B. amount of water in the stream
C. type of material through which the stream flows
D. minerals dissolved in the stream
Answer:
1 B
2A
#D
3B
1D
2B
3C
4A
A,C,A,B
C,A,C,A
C,A,A,B
Explanation:
Easy ive done this brings back memories
In ecosystem, particles are carried as bed load by rubbing particles together.Path of stream can be varied depending on amount of humus present in soil and is measured in cubic meters per second and carrying capacity depends on type of material through which stream flows.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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How does a longshore current change the beach
Answer:
As this sheet of water moves on and off the beach, it can “capture” and transport beach sediment back out to sea. This process, known as “longshore drift,” can cause significant beach erosion.
First person to comment there crush name get brainlyest
Answer:
:0
Explanation:
David <3
What is an atomic nucleus
Answer:
The atomic nucleus is the small, dense region consisting of protons and net at the center of an atom.
Explanation:
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. ... Protons and neutrons are bound together to form a nucleus by the nuclear force.
Answer:
The atomic nucleus is the small , dense region consisting of protons and neutrons at the center of an atom .