You can use this formula to help:
[tex]c = \frac{q}{m \: \times \: change \: in \: t} [/tex]
Where:
C = specific heat
q = heat
m = mass
t = temperature
What we know:
C = unknown
q = 956 J
m = 45 g
change in t = 12°C because 37°C - 25°C = 12°C
Plug known values into the formula:
C = 956 J / (45 g) (12°C) and we are left with a specific heat of 1.77J/g°C
Now, convert Joules to calories and then you get:
Answer: A. 0.423 cal/g°C
If the temperature of the alloy is 37°C, 0.423 cal/g°C. is its specific heat. The correct answer is A.
To find the specific heat of the alloy, we can use the formula:
Q = mcΔT
where:
Q = heat absorbed (in joules)
m = mass of the alloy (in grams)
c = specific heat of the alloy (in cal/g°C)
ΔT = change in temperature (in °C)
We are given Q = 956 J, m = 45 g, ΔT = (37°C - 25°C) = 12°C. Now, we need to convert the heat and temperature from joules to calories:
1 cal = 4.184 J
Q = 956 J * (1 cal / 4.184 J) = 228.74 cal
Now, we can rearrange the formula to solve for c:
c = Q / (m * ΔT) = 228.74 cal / (45 g * 12°C) ≈ 0.423 cal/g°C
Therefore, the correct answer is A. 0.423 cal/g°C.
To know more about specific heat, here
brainly.com/question/31608647
#SPJ2
The following table shows the symptoms in four patients. Each patient suffers from a different disease.
Patient Disease Cause Symptom
A Tuberculosis Bacteria Chest pain, coughing
B Polio Virus Paralysis
C Stomach cancer Environmental Stomach pain, vomiting, nausea
D Food poisoning Bacteria Vomiting, loose stools
Which patient's digestive system is affected by an infectious agent? (5 points)
A
B
C
D
Answer:
D. Food poisoning, Bacteria Vomiting, loose stools
Predict the products formed by the double replacement reaction between CaCl2(aq) and Na3PO4(aq). Explain your reasoning.
Answer:
3CaCl₂ + 2Na₃PO₄ → Ca₃(PO₄)₂ + 6NaCl.
Explanation:
Double replacement reaction is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products.The reaction between CaCl₂ and Na₃PO₄ is:3CaCl₂ + 2Na₃PO₄ → Ca₃(PO₄)₂ + 6NaCl.
Ca replaces Na in (Na₃PO₄ ) and forming Ca₃(PO₄)₂.
Na replaces Ca in CaCl₂ and forming NaCl.
So, the products of this reaction are Ca₃(PO₄)₂ and NaCl.
Need help on this ASAP !!!!
Answer:
3 moles
Explanation:
This question is on stoichiometry of reactions
Given
2H₂ +O₂⇒2H₂O-------------------the equation is balanced
Find the mole ratio
2H₂ +O₂⇒2H₂O
2 1 2
O:H = 2:1---------------------------------every mole of hydrogen requires two moles of oxygen to complety react
Thus given 6 moles of hydrogen;
O:H
?:6
=6/2=3 moles
1. One of the essential minerals in the human body is salt. How much salt is in the average adult human body?
A. 1 kilogram
B. 500 grams
C. 250 grams
D. practically none
This is often argued over, but most people agree it is somewhere within the 200s. So I think 250 is your best bet.
Yes I agree, the answer is C) 250 grams since the average human body contains around 200 grams.
If the actual yield of a reaction is 37.6 g while the theoretical yield is 112.8 g what is the percent yield
The answer is:
The percent yield of the reaction is 32.45%
Why?To calculate the percent yield, we have to consider the theoretical yield and the actual yield. The theoretical yield as its name says is the yield expected, however, many times the difference between the theoretical yield and the actual yield is notorious.
We are given that:
[tex]ActualYield=37.6g\\TheoreticalYield=112.8g[/tex]
Now, to calculate the percent yield, we need to divide the actual yield by the theoretical and multiply it by 100.
So, calculating we have:
[tex]PercentYield=\frac{ActualYield}{TheoreticalYield}*100\\\\PercentYield=\frac{37.6g}{112.8g}*100=0.3245*100=32.45(percent)[/tex]
Hence, we have that the percent yield of the reaction is 32.45%.
Have a nice day!
We need to find what percent 37.6 is out of 112.8 .
First find what fraction of 112.8 it is: (37.6/112.8) = 1/3
Change the number to a percentage: (1/3 x 100) = (33 and 1/3) %
1. Balance the following decomposition of NaHCO3.
NaHCO3 →
Na2CO3 +
CO2 +
H2O
Explanation:
Plato (This message is here to bypass the word limit thingy)
Need help asap!!!!! Plz
Answer:
153.8 g/mol.
Explanation:
The molar mass of a compound = ∑ atomic masses of atoms.
∴ The molar mass of CCl₄ = 1(atomic masss of C) + 4 (atomic mass of Cl) = (12.0 g/mol) + 4 (35.45 g/mol) = 153.8 g/mol.
Al(s0 + HCl (aq) ---> AlCl3(aq) + H2(g) what are the products in this reaction?
Answer:
[tex]AlCl_{3}_{(aq)}+H_{2}_{(g)}[/tex]
Aluminum Chloride and Hydrogen Gas
Explanation:
In a chemical equation the reactants are found on the left side of the equation and the products are found on the right side of the equation.
Reactants Products
A + BC → AC + B
So in this reaction, AlCl₃ and H₂ are the products.
If we were to name the products, you have Aluminum chloride and Hydrogen gas.
Need help on this ASAP !!!!
Answer:
2Na + K₂S → 2K + Na₂S. "replacement reaction"
Explanation:
To balance the equation, you should apply the law of conservation of mass for the equations.
The law of conservation of mass states that the no. of each atom is equal in both sides (reactants and products).
So, the given equation is balanced as:
2Na + K₂S → 2K + Na₂S.
It is a replacement reaction that Na replace K in K₂S.
That 2.0 moles of Na react with 1.0 mole K₂S to produce 2.0 of K and 1.0 mole of Na₂S.
The no. of all atoms is the same in both of reactants and products side.Na (2), K (2), and S (1).
Based on the map which answer best explains major concern in the union governmental offices during the war
The major concern for the Union government offices during the war was that the Confederate states managed to win a battle in very close proximity to their capital Washington. The fact that the Confederate forces were so close to Washington, and the defenses of the capital were very strong at the moment, while the majority of the soldiers were at other locations and needed time to get back to defend it. This was bringing a big concern because if Washington was captured by the Confederate forces then the Union would have been in big trouble and suffer badly because of it.
Answer:
Moving battles farther up the Northeast coast
Explanation:
a gymnast jumps from a great height onto a sealed mat filled with air.
what happens to the gas particles inside the mat during the impact?
A) the gas particles undergo a chemical reaction
B) the gas particles squeeze closer together
C) the gas particles become smaller
The gas particles squeeze closer together
B) the gas particles squeeze closer together.
A 5.0-gram sample of gold and a 5.0-gram sample of iron both absorb exactly 25 calories of energy. The specific heat of gold is 0.03 cal/g°C. The specific heat of iron is 0.11 cal/g°C. Which of the following statements is true?
The gold sample will experience a greater increase in temperature.
The iron sample will experience a greater increase in temperature.
Both samples will experience the same increase in temperature.
Answer:
The gold sample will experience a greater increase in temperature.
Explanation:
To solve this problem, we can use the relation:Q = m.c.ΔT,
where, Q is the amount of heat absorbed by substance.
m is the mass of the substance.
c is the specific heat of the substance.
ΔT is the difference between the initial and final temperature.
∴ ΔT = Q /(m.c)
It is clear that ΔT is inversely proportional to the specific heat capacity of the object.
So, the object with the smallest specific heat capacity (gold) will have the greater increase in temperature.
The increase in T can be calculated for both objects:
For gold:
ΔT = Q /(m.c) = (25 cal)/(5.0 g)(0.03 cal/g°C) = 166.7°C.
For iron:
ΔT = Q /(m.c) = (25 cal)/(5.0 g)(0.11 cal/g°C) = 45.45°C.
So, the right choice is:The gold sample will experience a greater increase in temperature.
Answer:
The gold sample will experience a greater increase in temperature.
Explanation:
Which statement describes how heat flows from the coffee to the part of the spoon in the coffee?
Answer:
Heat flows from the coffee to the spoon through conduction
Explanation: I took did the lab assignment
Heat flows from the coffee to the spoon through conduction. Therefore, option C is correct.
Conduction is one of the three main modes of heat transfer, alongside convection and radiation. It refers to the transfer of heat energy through direct contact between objects or substances that are at different temperatures.
Conduction occurs more efficiently in materials that are good conductors of heat, such as metals, which have closely packed atoms and free electrons that can easily transfer thermal energy. Materials with poor conductivity, such as insulators like wood or plastic, impede the transfer of heat by conduction.
Learn more about conduction, here:
https://brainly.com/question/31201773
#SPJ4
Your question is incomplete, most probably the full question is this:
Which statement describes how heat flows from the coffee to the part of the spoon in the coffee?
A. Heat flows from the coffee to the spoon through radiation.
B. Heat flows from the coffee to the spoon through convection.
C. Heat flows from the coffee to the spoon through conduction.
D. Heat flows from the coffee to the spoon through radiation, convection, and conduction.
Why would a doctor most likely restrict a patient’s contact with other people while the patient receives internal radiation?
Answer:
Explanation:
Radioactive material can leave the patient’s body through saliva, sweat, and urine
Answer:
Radioactive material can leave the patient's body through saliva, sweat, and urine.......
Explanation:
Calculate the molarity of a saline solution prepared by dissolving 41.2g of sodium chloride in 550mL of water.
Answer:
1.282 M.
Explanation:
Molarity is defined as the no. of moles o solute dissolved in a 1.0 L of the solution.M = (no. of moles of solute) / (V of solution (L))
M = (mass/molar mass)of NaCl / (V of solution (L))
mass of NaCl = 41.2 g, molar mass of NaCl = 58.44 g/mol, V of solution = 550 mL = 0.55 L.
∴ M = (mass/molar mass)of NaCl / (V of solution (L)) = (41.2 g / 58.44 g/mol) / (0.55 L) = 1.282 M.
When baby birds are ready to hatch out of their eggs, they peck on the inside of their shells until they can get out. This is an example of A. an inherited behavior. B. a learned behavior. C. a feedback loop. D. an autoimmune response. Reset
Answer:
The answer is A
Explanation:
An inherited behavior is a behavior that a creature has from birth. The baby knows to peck out of the shell before it was even technically born
Fill in the coefficients that will balance the following reaction:
a0C3H7OH +
a1O2 →
a2CO2 +
a3H2O
Answer:
a0 = 2
a1= 9
a2= 6
a3= 8
Explanation:
The equation for the reaction is;
C3H7OH + O2 → CO2 + H2O
To balance the chemical equation we introduce coefficients;
Therefore the balanced chemical equation will be;
2C3H7OH + 9O2 → 6CO2 + 8H2O
Chemical equations are balanced to ensure the law of conservation of mass is obeyed, such that the mass of the reactants is equivalent to that of the products.
The problem is a chemistry problem which involves balancing a chemical equation. The given equation (C3H7OH + O2 → CO2 + H2O) can be balanced with coefficients: 1 for C3H7OH, 5 for O2, 3 for CO2, and 4 for H2O resulting in a balanced equation: 1C3H7OH + 5O2 → 3CO2 + 4H2O.
Explanation:The problem you have presented is a classic chemistry problem involving balancing a chemical equation. In the given equation: a0C3H7OH + a1O2 → a2CO2 + a3H2O, these are the coefficients that will balance the equation: a0 = 1, a1 = 5, a2 = 3 and a3 = 4. This means, the balanced equation would be: 1C3H7OH + 5O2 → 3CO2 + 4H2O. Balancing a chemical equation is a fundamental aspect of stoichiometry in chemistry and is based on the law of conservation of mass.
Learn more about Balancing Equations here:https://brainly.com/question/7181548
#SPJ3
The number of moles of solute in 200.ml of a 0.500 m solution is
Answer:
I believe the answer is 0.100.
Explanation:
Hope my answer has helped you!
Final answer:
To find the number of moles in 200 ml of a 0.500 M solution, convert the volume to liters (0.200 L) and multiply by the molarity to get 0.100 moles of solute.
Explanation:
To calculate the number of moles of solute in a 200 ml solution with a molarity of 0.500 M, you would use the formula:
Number of moles (mol) = Molarity (M)× Volume (L)
First, it is critical to convert the volume from milliliters to liters, knowing that there are 1000 ml in a liter:
200 ml is equivalent to 0.200 L.Next, you would use the given molarity of the solution to determine the moles of solute:
Moles of solute = 0.500 mol/L×0.200 LMoles of solute = 0.100 molSo, the solution contains 0.100 mol of solute.
Moon is related to planet in the same way that planet is related to _____________. A. Orbit
B. Sun
C. Neptune
D. Dwarf planet
Answer:
sun
Explanation:
Final answer:
A moon orbits a planet, and a planet orbits the Sun, completing the analogy and indicating 'Sun' is the correct answer to fill in the blank.
Explanation:
The question requires drawing an analogy between celestial bodies based on their relationships within the solar system. A moon orbits a planet, and similarly, a planet orbits something else. The best answer to what a planet orbits is the Sun, which is at the center of our solar system.
We know that all the planets in our solar system, including Earth, revolve around the Sun. This is due to the Sun's gravitational pull, which keeps the planets in their respective orbits. Likewise, moons, including Earth’s moon, orbit their respective planets due to the gravitational pull of these planets.
Therefore, the analogy completes as follows: Moon is to planet as planet is to Sun. The correct choice is B. Sun.
Which of the following is an example of diffraction
Diffraction is the bending of a wave around the edges of an opening or obstacle. Examples of diffraction include Young's double-slit experiment, where light passing through two slits produces a diffraction pattern, and waves diffracted off crystal planes according to the Bragg equation, resulting in constructive or destructive interference.
Explanation:Diffraction is best described as a wave characteristic. It refers to the bending of a wave around the edges of an opening or an obstacle. This phenomenon is observed for all types of waves. When we pass light through smaller openings or slits, for instance, we observe that light behaves as a wave and bends just like sound does in a similar situation.
One example of such an occurrence is Young's double-slit experiment wherein light of a single wavelength passes through a pair of slits. As a result, we observe a diffraction pattern consisting of numerous vertical light and dark lines spreading out exponentially. In simple terms, if there were no diffraction or interference, the light would merely produce two direct lines on the screen.
Another example as illustrated in figure 10.64 is a phenomenon described by the Bragg equation. This refers to waves being diffracted off two different crystal planes at the Bragg angle resulting in constructive interference, or at a different angle causing destructive interference.
Learn more about Diffraction here:https://brainly.com/question/12290582
#SPJ12
Among the given options, the rainbow patterns found on a CD (Option D) are an example of diffraction, demonstrating the interference and bending of light waves as they interact with the grooves on the CD's surface.
Diffraction is a phenomenon related to the bending of waves as they encounter obstacles or pass through small openings. Among the options provided:
A. The blue color of the sky is primarily a result of Rayleigh scattering, not diffraction. Rayleigh scattering occurs when sunlight interacts with molecules and small particles in the Earth's atmosphere, causing shorter wavelengths (like blue) to scatter more than longer wavelengths.
B. The twinkling of the stars is caused by atmospheric turbulence, leading to changes in the refractive index of air. While this phenomenon is related to light passing through varying atmospheric conditions, it is not a direct example of diffraction.
C. The Tyndall effect is the scattering of light by colloidal particles in a transparent medium, making the beam of light visible. This effect is more associated with scattering than diffraction.
D. Rainbow patterns found on a CD are indeed an example of diffraction. The microscopic grooves on the surface of a CD act as a diffraction grating, causing the incident light to diffract into its spectral components, creating the colorful patterns observed.
Learn more about Diffraction here:
https://brainly.com/question/12290582
#SPJ6
The question probable may be:
Which of the following is an example of diffraction
A. The blue color of the sky
B. the twinkling of the stars
C. the tyndall effect
D. rainbow patterns found on a CD
PLEASE HURRY! MARKING BRANLIEST IF CORRECT!!
Which phrases describe the atmosphere? Check all that apply.
protects Earth’s surface
contains a mixture of gases and particles
includes organisms in the air, on land, and in water
consists of rocks, minerals, landforms, and Earth’s interior
comprises oceans, lakes, rivers, streams, and groundwater
The atmosphere is a bunch of air/gases that protect the Earth. Nothing living is included in the atmosphere. Therefore the answers are...
Protects Earth's surface
Contains a mixture of gases and particles
Hope this helped!
Answer: protects Earth’s surface
contains a mixture of gases and particles
includes organisms in the air, on land, and in water
Explanation:
An atmosphere is the layer of gases that surrounds the earth. It is composed of air masses that consists of variety of gases like water vapor, oxygen, nitrogen, and carbon dioxide. It also consists of particles of dust and pollutants.
The function of the atmosphere is to protect the earth surface from the incident infrared rays and ultraviolet rays coming from the sun. The atmosphere covers the land and water region. Therefore, the lives of organisms that survive in air, land and water depends on the atmosphere.
How much force is required to lift a rock a vertical distance of 8 m if 80 j of work were done
we have
work done (W)= force(F) × displacemen(s)
or, 80= F× 8
or, F= 10 N
therefore, 10 N force is required to lift the rock.
Final answer:
To calculate the force needed to lift a rock 8 m when 80 J of work is done, use the formula W = F × d, resulting in a force requirement of 10 N.
Explanation:
To find out how much force is required to lift a rock a vertical distance of 8 m when 80 J of work were done, we can use the relationship between work done, force, and distance. The work done when lifting an object is defined by the formula W = F × d, where W is the work, F is the force, and d is the distance. In this case, W = 80 J and d = 8 m. By rearranging the formula to solve for F, we get F = W/d. Therefore, the force required to lift the rock is F = 80 J / 8 m = 10 N.
Need help on this ASAP !!!!
Answer:
2KClO₃ → 2KCl + 3O₂. "decomposition reaction"
Explanation:
To balance the equation, you should apply the law of conservation of mass for the equations. The law of conservation of mass states that the no. of each atom is equal in both sides (reactants and products). The balanced equation is:2KClO₃ → 2KCl + 3O₂.
It is a decomposition reaction that 1.0 reactant is decomposed to 2 products.
That 2.0 mole of KClO₃ are decomposed to produce 2.0 moles of KCl and 3.0 moles of O₂.
The no. of all atoms is the same in both of reactants and products side.K (2), Cl (2), and O (6).
What are the products of the reaction between aluminum and copper nitrate?
aluminum and aluminum nitrate
copper and aluminum
copper and aluminum nitrate
copper and copper nitrate
Answer:
Copper and aluminium nitrate
Explanation:
The reaction is a simple redox reaction. Where copper ions are reduced to copper atoms and the aluminium atoms oxidized to aluminium ions.
The equation for the reaction is as follows:
2Al₍s₎ + 3Cu(NO₃)₂₍aq₎ ⇒ 2Al(NO₃)₃ + 3Cu₍s₎
The ionic equation:
2Al₍s₎ + 3Cu²⁺₍aq₎⇒2Al³⁺₍aq₎ + 3Cu₍s₎
Answer:
copper and aluminum nitrate
Explanation:
Aluminum is more reactive than copper. So, aluminum will replace copper in the nitrate compound, and pure copper will be produced.
• How can pollution affect water as a resource?
Answer:
Dead fish, birds, dolphins, and many other animals often wind up on beaches, killed by pollutants in their habitat.
If an atom has 1 to 3 valence electrons, what will it do?
-move electrons to a lower shell
-accept electrons
-move electrons to a higher shell
-donate electrons
Answer:
[tex]\boxed{\text{donate electrons}}[/tex]
Explanation:
An atom with one to three valence electrons would have to gain seven to five valence electrons, respectively to get a stable octet.
It is easier for it to donate electrons and expose the stable octet of electrons in the shell below..
(A) is wrong. You can't move electrons to a lower shell, because it's already full.
(B) is wrong. The atom will donate electrons.
(C) is wrong. Moving electrons to a higher shell will make the atom more unstable.
which is more reactive, Rubidium or Hydrogen?
Answer:rubidium is the second most reactive metal so it is more reactive than hydrogen
Explanation:
Final answer:
Rubidium is more reactive than hydrogen, especially when reacting with water. It is part of the alkali metals that are highly reactive due to their position in the periodic table, while hydrogen, despite its reactivity, is less reactive with water and forms covalent compounds.
Explanation:
Between rubidium and hydrogen, rubidium is more reactive when it comes into contact with water. This is demonstrated by the vigorous and instantaneous reaction that occurs when rubidium solid is added to water, often resulting in an explosion. This reactivity is due to its position in the periodic table as an alkali metal, which are known for their high reactivity with water. In contrast, hydrogen, although reactive with some elements, has a lower reactivity towards water and forms covalent compounds with various elements.
The chemical equation 2 Rb(s) + 2 H₂O(l) → 2 RbOH(aq) + H₂ (g) depicts this reaction more accurately than a reaction in equilibrium with a low concentration of hydronium ions, as it conveys the fast and vigorous nature of the interaction between rubidium and water. The alkali metals, which include lithium, sodium, potassium, rubidium, cesium, and francium are part of Group 1 of the periodic table and are known for their reactivity, especially with water.
1. What is heat capacity?
2. What is specific heat?
3. You have a 10 gram piece of aluminum and a 10 gram piece of gold sitting in the sun. Which metal will warm by ten degrees first?
4. You have a 20 gram piece of aluminum and a 40 gram piece of aluminum sitting in the sun. Which piece will arm by ten degrees first?
Answer:
1. Heat capacity is the ratio of the amount of heat energy transferred to an object to the resulting increase in its temperature.
2. Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass.
3. The gold will warm by ten degrees first because it needs a low amount of heat (12.9 J) while Aluminium needs (90.3 J).
4. The 20 gram piece of aluminum will warm first.
Explanation:
1. What is heat capacity?
Heat capacity is the ratio of the amount of heat energy transferred to an object to the resulting increase in its temperature.
2. What is specific heat?
Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass.
3. You have a 10 gram piece of aluminum and a 10 gram piece of gold sitting in the sun. Which metal will warm by ten degrees first?
The amount of heat absorbed by Al or Au (Q) can be calculated from the relation:Q = m.c.ΔT.
where, Q is the amount of heat absorbed by Aluminium or gold (Q = ??? J),
m is the mass of Aluminium or gold (m = 10.0 g),
c is the specific heat capacity of Aluminium or gold (c of Al = 0.902 J/g °C, c of Au = 0.129 J/g °C),
ΔT is the temperature difference (final T - initial T) (ΔT = 10.0°C).
Q is the amount of heat absorbed by Aluminium = m.c.ΔT = (10.0 g)(0.902 J/g °C)(10.0°C) = 90.2 J.Q is the amount of heat absorbed by Gold = m.c.ΔT = (10.0 g)(0.129 J/g °C)(10.0°C) = 12.9 J.
So, the gold will warm by ten degrees first because it needs a low amount of heat (12.9 J) while Aluminium needs (90.3 J).
4. You have a 20 gram piece of aluminum and a 40 gram piece of aluminum sitting in the sun. Which piece will warm by ten degrees first?
∵ Q ∝ m.
∴ The piece of higher mass (40 g) will needs a heat larger twice than that needed to warm the (20 g) piece.
So, the 20 gram piece of aluminum will warm first.
Heat capacity is the amount of heat energy necessary to change the temperature of a substance, while specific heat is similar but normalized to the mass of the substance. Therefore, substances with higher specific heat heat up more quickly. Aluminum has a higher specific heat than gold, so it will heat up more quickly when exposed to the sun.
Explanation:Heat capacity is the amount of heat energy required to raise the temperature of a substance by a given amount. It's measured in joules per degree Celsius (J/°C).
On the other hand, specific heat refers to the amount of heat energy required to raise the temperature of a specific quantity (typically 1 gram or 1 kilogram) of a substance by one degree Celsius. It's a characteristic property of a substance, and its units are usually Joules per gram degree Celsius (J/g°C).
Regarding the two 10 gram pieces of aluminium and gold sitting in the sun, aluminium will heat up faster. This is because aluminium has a higher specific heat compared to gold, meaning it requires less energy to increase its temperature.
For the 20 gram and 40 gram pieces of aluminium, the 20 gram piece will warm faster by ten degrees given that it has less mass and therefore needs less energy to increase its temperature.
Learn more about Heat Capacity and Specific Heat here:https://brainly.com/question/28302909
#SPJ3
Cobalt-60 can be used by scientists for the purpose of radioactive dating. Cobalt-60 has a half-life of 5,272 years. A fossilized rock originally contained 25 grams of Co-60. When tested, the rock only contains 6.25 grams of Co-60. Approximately how old is the item?
A) 2,600 years
B) 5,200 years
C) 10,500 years
D) 15,600 years
the correct answer is C
Answer:
C) 10,500 years.
Explanation:
The decay of cobalt-60 is a first order reaction.The rate constant of the reaction (k) in a first order reaction = ln (2)/half-life = 0.693/(5272 year) = 1.314 x 10⁻⁴ year⁻¹.The integration law of a first order reaction is:
kt = ln [A₀]/[A]
k is the rate constant = 1.314 x 10⁻⁴ year⁻¹.
t is the time = ??? years.
[A₀] is the initial percentage of cobalt-60 = 25.0 g.
[A] is the remaining percentage of cobalt-60 = 6.25 g.
∵ kt = ln [Ao]/[A]
∴ (1.314 x 10⁻⁴ year⁻¹)(t) = ln (25.0 g)/(6.25 g)
(1.314 x 10⁻⁴ year⁻¹)(t) = 1.386.
∴ t = 1.386/(1.314 x 10⁻⁴ year⁻¹) = 10,550 years ≅ 10,500 years.
Answer:
answer is c
Explanation:
The pressure on 2.50 L of gas changes from 100 kPa to 40 kPa. What is the new volume of the temperature is constant?
Answer: 6.25 L (6L if sig figs)
Explanation:
The relationship between pressure and volume is inverse when temperature is constant, where P1V1=P2V2
P1 = 100
P2 = 40
V1 = 2.5
Plug in to get 100(2.5) = 40v2
Solve for v2 = 250/40 = 6.25 L
This makes sense because if the pressure decreases the volume increases.
if your teacher has you do sig figs and you kept the sig figs from the problem, then there should be 1 sig fig (from 40 kPa) so the answer would be 6 L.
The volume of the gas when temperature is constant is 6.25 L.
What is the relation between pressure and volume?Relation between the pressure and volume of the gas by using the ideal gas equation will be represented as:
P₁V₁ = P₂V₂, where
P₁ & V₁ are the initial pressure and volume.
P₂ & V₂ are the final pressure and volume.
On putting values from the question, we get
V₂ = (100)(2.5) / (40) = 6.25 L
Hence required volume is 6.25 L.
To know more about ideal gas equation, visit the below link:
https://brainly.com/question/25290815
#SPJ2