The atomic number represents the number of protons, whereas the mass number represents the quantity of protons and neutrons. The number of protons equals the amount of electrons.
In a Bohr diagram, where do you determine the number of neutrons?The atomic number is the number of protons. The number of neutrons may be calculated by subtracting the number of protons from the atomic mass, which is then rounded to the closest whole number.
For neutrally charged species, the number of electrons in an atom equals the atomic number of an element. This signifies that the number of electrons and protons in an element are equal. As a result, the number of electrons in oxygen is eight.
The number of valence electrons in neutral atoms equals the atom's main group number. A periodic table column can be used to determine an element's main group number. Carbon, for example, belongs to group 4 and contains four valence electrons.
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The diameter of the he atom is approximately 0.10 nm. calculate the density of the he atom in g/cm3 (assuming that it is a sphere).
The density of the He atom is 12.69 g/cm³.
d(He) = 0.1 nm = 1 × 10⁻⁸ cm; a diameter of helium atom
V(He) = 1/6 × (1 × 10⁻⁸ cm)³ × 3.14
V(He) = 5.23 × 10⁻²⁵ cm³; volume of helium atom
m(He) = 4 amu; mass of helium atom
d(He) = m(He) / V(He)
d(He) = 4 × 1.66 × 10⁻²⁴ g / 5.23 × 10⁻²⁵ cm³
d(Cr) = 12.69 g/cm³; density of the helium atom
Volume of the helium is the measure of the amount of space occupied by the helium.
Diameter or the atomic radius of an atom is a measure of the size of that atom. It is distance from the center of the nucleus to the outermost isolated electron of an atom.
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Rubidium-86 (86Rb) undergoes beta decay. A 9.52 x 10^−5 mol sample of 86Rb emits 8.87 x 10^16 beta particles in one hour. Calculate the half-life (in hours) for 86Rb
The half-life (in hours) for 86Rb is mathematically given as
half-life= 447.1 hr
This is further explained below.
What is the half-life (in hours) for 86Rb?Generally, the equation for k is mathematically given as
k = (1/t)ln(a/x)
Where
No of mol of Beta particle
β= (8.87*10^16/(6.023*10^23))
β = 1.47*10^-7 mol
Therefore
k = (9.52*10^-5)-(1.473*10^-7)
= 9.50527*10^-5 mol
Hence
k = (1/1)ln((9.52*10^-5)/(9.50527*10^-5))
k = 0.693/t0.5
t0.5=half lifetime
t0.5= 0.693/(0.00155)
half-life= 447.1 hr
In conclusion, the half-life (in hours) for 86Rb
half-life= 447.1 hr
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___________ is a dangerous concept because toxic chemicals concentrate as they pass up the food chain. group of answer choices
Biomagnification is a dangerous concept because toxic chemicals concentrate as they pass up the food chain. group of answer choices
What is biomagnification?
Biomagnification is defined as the accumulation of a particular substance in the body of the organisms at different trophic levels of a food chain. An example for biomagnification is the accumulation of insecticide DDT which gets accumulated in zooplanktons. Zooplanktons are those which consumes small fishes.In the entire food chain or in the predators, the chemical toxic will gets increased.It makes all the animals to get more impact and also it makes the food chain to the higher toxic.Biomagnification can be also known as the biological magnification.Also in plants, if a farmer sprays pesticides on the crops which enters the food chain from crops these pesticides enter into the organisms that feed on it.Learn more about Biomagnification,
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What is the purpose of the sodium sulfate? Why did you rinse the sodium sulfate with an additional portion of methylene chloride?
sodium sulfate binds to water and forms a precipitate to ensure a pure solution of methylene chloride.
When you want to ensure a pure solution of methylene chloride, one way to do it is to add sodium sulfate to bind with the water. This forms a precipitate, which can then be removed from the solution. This leaves you with a purer solution of methylene chloride that can be used for your needs.
Sodium sulfate is a common precipitant in the purification of methylene chloride. When added to water, it forms a precipitate that ensures a pure solution of methylene chloride. This process is known as binding, and it is an essential step in ensuring the quality of the final product.
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A molecule with 4 single bonds (and any number of lone pairs) could have which type of molecular geometry?
A molecule with 4 single bonds (and any number of lone pairs) could have the tetrahedral geometry.
For example carbon(IV) chloride (CCl₄). There are four single covalent bonds between one carbon atom and four chlorine atoms (see the picture below).
Carbon has sp3 hybridization (hybridize one s-orbital and three p-orbitals) and four chlorine atoms are positioned symmetrically as corners in a tetrahedral configuration. Because of symmetrical geometry, carbon tetrachloride is non-polar molecule.
Electron configuration of carbon: ₆C 1s² 2s² 2p².
Electron configuration of chlorine: ₁₇Cl 1s² 2s² 2p⁶ 3s² 3p⁵.
The ammonium ion has exactly the same shape as methane, because it has exactly the same electronic arrangement, ammonium ion is tetrahedral (sp3 hybridized).
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Ivr Which order shows the levels of organization from largest to smallest? organism, organ system, cell, organ, tissue organism, tissue, organ system, organ, cell organism, organ, organ system, cell, tissue organism, organ system, organ, tissue, cell
The levels of organization from largest to smallest are - organism, organ system, organ, tissue, and cell.
Therefore, option (D) is correct.
The cell is the basic or fundamental unit of life of an organism.
A Group of cells with similar shapes and functions combines to form tissues.
Then the tissues organize to form organs.
A group of organs with similar functions combine to form an organ system.
A group of organ systems organizes to form an organism.
Hence, the correct order of levels of organization from largest to smallest is - organism, organ system, organ, tissue, and cell.
Option (D) is correct.
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calculate ionisation energy of hydrogen
2.18 x 10⁻¹⁸ J/atom is the ionisation energy of hydrogen.
The minimum energy required by an electron in an atom or ion to come out from the control of the nucleus is known as ionisation energy. It measures the capability of an element which can take part in a chemical reaction by accepting or donating electrons. It is expressed in electron volt (eV).
It will help in the understanding of the reactivity of the chemical compounds.
For Ionisation energy formula
1/λ =R[1/n₁²-1/n₂²]
n₁=1 n₂= ∞
R=1.0974 x10¹⁷m⁻¹
1/λ =1.0974 x10¹⁷m⁻¹x[1/1-0] ( 1/ ∞=0)
λ=9.116x10⁻⁸m
E=hc/λ
h=6.63x10⁻³⁴Js c=3x10⁸m/s λ = 9.116x10⁻⁸m
E=(6.63x10⁻³⁴Js x 3x10⁸m/s) ÷ 9.116x10⁻⁸m
E=2.18x10⁻¹⁸J/atom.
Ionisation energy of Hydrogen is 2.18x10⁻¹⁸J/atom.
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John wants to prove that the paved area of the playground is hotter than the grassy area of the playground. He measures the temperature of each area at three different times of the school day and records the temperatures. He does this for five days in a row. Thomas wants to replicate John's experiment. Which statement describes a situation that could cause Thomas's data to vary from John's data?
The statement that describes a situation that could cause Thomas's data to vary from John's data is as follows: Thomas measures the temperatures only on the sunny days.
How is an experiment replicable?An experiment is usually conducted under controlled conditions to test a hypothesis or determine the validity of an existing truth.
According to this question, John wants to prove that the paved area of the playground is hotter than the grassy area of the same playground. He measures the temperature of each area at three different times of the school day and records the temperatures.
However, Thomas wants to replicate this experiment carried out by John. To get the same results after replication, one must ensure to control every variable that was initially controlled.
Therefore, this means that if Thomas measures the temperatures only on the sunny days, he will get a different data from John's data because John measured the temperature on three different times of school days.
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what doed 2n2 denote ? Explain it with the help of two example.
The formula 2n^2 is used to find the number of electrons in a shell.
What does 2n^2?Atoms are composed of electrons in shells in addition to the protons and the neutrons in the nucleus. Electrons are known to be found in shells. The shells are arranged in order of increasing energy; KLMN. It is often important to find the number of electrons that could be found in a particular shell of an atom.
We can find the number of electrons in a shell or energy level by the use of the formula 2n^2. We know that the shells KLMN corresponds to 1, 2, 3, 4 ...
Using this model, the electrons in the K shell are 2(1)^2 = 2
Electrons in the L shell are; 2(2)^2 = 8 etc
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Explain in four sentences or less why menthone and isomenthone do not separate in capillary electrophoresis.
Capillary electrophoresis separates charged species according to their charge and size. Since menthone and isomenthone are stereoisomers, they have the same size and charge. As a result, they do not separate because they migrate at the same speed on electrophoresis.
Capillary electrophoresis is an analytical technique that separates ions based on their electrophoretic mobility using an applied voltage. Electrophoretic mobility depends on molecular charge, viscosity, and atomic radius.
Menthone is a mint-flavored monoterpene that is naturally present in many essential oils. l-Menthone is the most common of the four possible stereoisomers in nature, shown to the right. It is structurally related to menthol and has a secondary alcohol instead of a carbonyl.
Because of the same charge and size they do not separate through because they migrate at the same speed on electrophoresis.
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Enzymes are specific or picky. So the enzyme that works with a chemical reaction of triglycerides will.
Enzymes are specific or picky. So the enzyme that works with a chemical reaction of triglycerides will work with more triglycerides.
In living organisms, enzymes are kinds of proteins that work as catalysts and accelerate the rate of chemical reactions without consuming themselves.
Enzymes are essential ingredients for humans as they are responsible for respiration, nerve function, and food digestion.
Moreover, these proteins are also vital for catabolic and anabolic reactions as they build and break substances.
These are found in all living things and are synthesized naturally in the human body.
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Law of Conservation of Mass Practice
1. 3Na + Cl₂ → 3NaCl
30g ? 76g
What is the mass of Cl₂?
What are the reactants?
What are the products?
Are the reactants elements or compounds?
Is the product an element or compound?
In the laboratory, a student dilutes 29.0 ml of a 7.71 m hydroiodic acid solution to a total volume of 200.0 ml. what is the concentration of the diluted solution?
The concentration of the diluted solution is 1.11M , using formula M1V1=M2V2 (whereM = molarity , V = volume).
The formula M1V1=M2V2 is the most widely used.
You must ensure that M stands for Molarity and V for Volume in Liters in this formula. You must divide 29.0 mL by 1,000 in order to convert this problem's mL to L units (mL =.0290 L).
M1 is the specified molarity (7.71M), and V1 is the specified molarity's volume (.0290 L).
The final molarity M2 is what we are looking for, and the final volume V2 equals 1000 L. (remember to convert the 200.0 mL to L)
Fill in the formula with your numbers.
(X) × (0.2000 L) = (7.71M) × (0.0290 L)
(7.71M) × (0.0290 L) / (0.2000 L) = (X)
1.11M = X
Given that we maintained the same number of moles in the solution, this makes sense.
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The amount of energy that must be absorbed or lost to raise or lower the temperature of 1gram of liquid water by 1°c.
The amount of energy that must be absorbed or lost to raise or lower the temperature of 1 gram of liquid water by 1°C is 1 calorie.
A calorie (cal), or a small calorie, is the amount of energy needed to heat one gram of water by one degree Celsius. It is used to express the amount of energy released in a phase change or chemical reaction.
One small calorie is approximately 4.2 joules.
A calorie is a unit of energy.
A calorie was originally part of the metric system (SI), but now it is replaced with the joule (J).
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Biodiversity is important for the sustainability of ecosystems. However, many of the human actions that are aimed at growing communities are decreasing the biodiversity of these areas, leaving populations and ecosystems vulnerable. As human populations grow, the terrestrial and aquatic ecosystems they use may be transformed by the efforts of human beings and biodiversity losses typically accompany these processes. Which of these actions decrease biodiversity and threaten sustainability? Select ALL that apply.
A Invasive (non-native) species may outcompete native species for food and habitat. Invasive (non-native) species may outcompete native species for food and habitat.
B Regulated hunting seasons artificially decrease hunted populations, often leading to extinctions. Regulated hunting seasons artificially decrease hunted populations, often leading to extinctions.
C Pollution from building and commercialization can create health problems in exposed organisms. Pollution from building and commercialization can create health problems in exposed organisms.
D Decreased use of pesticides and fertilizers can allow for increased damage to plant life. Decreased use of pesticides and fertilizers can allow for increased damage to plant life.
E Habitat destruction reduces or eliminates the food resources and living space for most species. Habitat destruction reduces or eliminates the food resources and living space for most species.
The actions by humans that decrease biodiversity and threaten sustainability are;
Regulated hunting seasons artificially decrease hunted populations, often leading to extinctions.Pollution from building and commercialization can create health problems in exposed organisms.Habitat destruction reduces or eliminates the food resources and living space for most species.What is biodiversity?The term biodiversity has to do with the existence of different species that exist in an ecosystem. In a given ecosystem, there could be several species that exist together. This biodiversity is very much important for the continuity of balance in nature.
The actions by humans that decrease biodiversity and threaten sustainability are;
Regulated hunting seasons artificially decrease hunted populations, often leading to extinctions.Pollution from building and commercialization can create health problems in exposed organisms.Habitat destruction reduces or eliminates the food resources and living space for most species.Learn more about biodiversity:https://brainly.com/question/13073382
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What is the ph of a 0.0100 m sodium benzoate solution? kb (c7h5o2-) = 1.5 x 10-10
The pH of a 0.0100 M sodium benzoate solution is 8.09.
c(C₆H₅COONa) = 0.0100 M; concentration of the salt sodium benzoate.
Balanced chemical equation for reaction of benzoate ion (from the salt sodium benzoate) with water:
C₆H₅COO⁻(aq) + H₂O ⇄ C₆H₅COOH(aq) + OH⁻(aq)
Kb = 1.5 × 10⁻¹⁰; constant of base
Kb = c(C₆H₅COOH) × c(OH⁻) / c(C₆H₅COO⁻)
c(C₆H₅COOH) = c(OH⁻) = x
1.5 × 10⁻¹⁰ = x² ÷ 0.0100 M
x = c(OH⁻) = 1.225 × 10⁻⁶ M
pOH = -log c(OH⁻)
pOH = -log (1.225 × 10⁻⁶ M)
pOH = 5.91
pH = 14 - 5.91
pH = 8.09
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The elements of a brand that cannot be spoken are called the ______. brand mark trademark brand name brand equity
The elements of a brand that cannot be spoken are called option(a)i.e, brand mark.
A brand mark is a logo, design element, artistic creation, or other visual representation that facilitates the quick identification of a particular company. Building and maintaining a brand's reputation is essential.
The brand mark is significant because it draws attention, makes an impact, establishes your brand identity, is memorable, sets you apart from rivals, fosters brand loyalty, and is well-liked by your target market.
However, when examining examples of brand markings, Pepsi is without a doubt the superior firm to take into account. Coca-Cola still employs its name as part of its design, in contrast to Pepsi, which may get by with nothing more than its recognizable white, blue, and red globe to draw customers' attention.
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A theory:
a. Must be constantly tested and revised
b. Should not be consistent with pre-existing theories
c. Should never be tested
d. Both A and B
Answer:
a. Must be constantly tested and revised
Explanation:
theories should constantly be tested and revised.
At a pressure of 476 kPa, the volume of a gas is 6.00cm3. Assuming the temperature remains constant, what will be the pressure when the volume is 3.50 cm3?
The pressure when the volume is 3.50 cm³ is 816 kPa
What is the relationship between the volume and pressure of a gas at constant temperature?Pressure and volume of a gas have an inverse relationship at constant temperature
The relationship between the volume and pressure of a gas at constant temperature is given by the equation of Boyle's law:
P₁V₁ = P₂V₂P₁ = 476 kPa
V₁ = 6.00 cm³
V₂ = 3.50 cm³
P₂ = P₁V₁/V₂
P₂ = 476 * 6 /3.50
P₂ = 816 kPa
In conclusion, pressure and volume are inversely related at constant temperature.
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PLEASE HELP ME IM ALMOST DONE WITH MY TEST
Which of the following statements about polyatomic ions is false?
Select one:
a. Polyatomic ions act like a single atom.
b. Each polyatomic ion has a single oxidation number.
c. Polyatomic ions are found in nature.
d. Polyatomic ions do not combine with ions of the opposite charge to form chemical compounds.
Answer:
D
Explanation:
Opposite charge
If urine has a density of 1.08 g/ml, what would be the mass of a 139 ml urine sample?
The urine sample with a density of 1.08 g/ml and a volume of 139 ml, has a mass of: 0.39 g
The density formula and the procedure we will use is:
ρ = m/v
Where:
v= volumeρ= densitym= massInformation about the problem:
ρ= 1.08 g/mlv= 139 mlm= ?Applying the density formula and clearing the mass (m), we get:
m = ρ * v
m = 1.08 g/ml * 139 ml
m = 150.12 g
What is density?It is a physical quantity that expresses the ratio of the body mass to the volume it occupies.
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What is the net force and direction of the block?
Answer: The object moves downward towards gravity
Explanation:
Gravity exerts a force of 600 N which is greater than the force exerted by air which is 200 N. Hence the object moves in the direction of the greater force applied. The net force is 600- 200= 400N.
Write equation for the following acid-base reaction.
f3ccoona + br3ccooh
express your answer as a chemical equation.
[tex]Br_{3} CCOOH[/tex]+[tex]F_{3} CCOONa[/tex] → [tex]F_{3} CCOONaH + Br_{3} CCOO^{-}[/tex]
What is the significance of chemical equations?Chemical equations show us the products of reactions as well as how they form. They can be used to predict the outcomes of a reaction. We can predict what will happen if magnesium (a metal) reacts with hydrochloric acid (an acid, of course!) using this rule.When one or more chemicals are converted into one or more other chemicals, a chemical reaction occurs. Examples include iron and oxygen reacting to form rust, and vinegar and baking soda reacting to form sodium acetate, carbon dioxide, and water.A chemical equation is a symbolic representation of a chemical reaction in the form of symbols and formulae, with the reactant entities on the left and the product entities on the right, with a plus sign between the entities in both the reactants and the products and an arrow pointing towards the products and indicating the direction of the reaction. The absolute values of the stoichiometric numbers are represented by the coefficients next to the symbols and formulae of entities. Jean Beguin drew the first chemical equation in 1615.
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What would happen to the
Moon if the Earth's mass
increased?
When the Earth's mass is increased moon would spiral toward Earth.
The Moon, the fifth-largest moon in the solar system, is the sole natural satellite of Earth. Our planet's wobble is lessened and our climate is moderated by the moon's existence. The Moon is approximately 240,000 miles away from Earth (385,000km). The exosphere, the Moon's extremely thin atmosphere,
Earth's gravitational pull is influenced by its mass. The moon would move towards earth if the mass increased since the gravitational force would likewise increase.Likewise,The moon would move farther away if the mass reduced since the gravitational force would likewise decrease.The moon is close to the earth and visible at night because of gravity.
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What is the net charge of the following amino acids at ph 1.0, 4.0, 8.0, and 12.0? (2 point each)
(a) histidine
(b) leucine
(c) aspartic acid
(d) tyrosine
(e) asparagine
Net charge
(a) histidine 0, +2, 0, -1
(b) leucine 0,
(c) aspartic acid 0
(d) tyrosine 0
(e) asparagine 0
What is ph ?
The hydrogen ion concentration is measured using the pH scale. The pH values, which range from 0 to 14, are assigned to it. Therefore, we may say that the pH value is a number that represents how acidic or basic a solution is.
A solution with a pH below 7 is referred to as acidic, and one with a pH over 7 is referred to as basic, or alkaline.
Thus, histidine has a net charge of 0 at ph 1, of 2 at ph 4 of 0 again at ph 8 and finally of -1 at ph 12.
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A solution is 0.0460 m lif. what is the molarity of the solution if the density is 1.10 g/ml?
a. 0.0418 m
b. 0.0417 m
c. 0.0506 m
d. 0.0441 m
e. 0.0460 m
The molarity of the solution is c. 0.0506 m.
b(LiF) = 0.0460 m; molality of the solution
Molality is concentration expressed in moles per kilogram.
d(LiF) = 1.1 g/ml; the density of the solution
M(LiF) = 26 g/moll; molar mass of the solute
The solute is the component present in small quantities in solution.
The relation between molarity and molality is c = 1000d / (1000/b + M)
c = 1000×1.1 / (1000/0.046 + 26)
c = 0.0506 M; the molarity of the solution
Molarity is defined as the number of moles of the solute per liter of the solution. It is denoted by M.
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Which quantity is held constant when working with Boyle's, Charles's, and Gay-Lussac's laws?
O volume
O moles
O pressure
O temperature
Answer:
moles
Explanation:
for these three principles, the volume, pressure and temperature of the particles will change whereas the moles will stay constant because the number of the particles does not change throughout the experiment.
Moles is held constant when working with Boyle's, Charles's, and Gay-Lussac's laws and the correct option is option 2.
What are Gas Laws?All gases generally show similar behaviour when the conditions are normal. But with a slight change in physical conditions like pressure, temperature or volume these show a deviation.
The gas laws are a group of laws that govern the behaviour of gases by providing relationships between the following:
The volume occupied by a gas.The pressure exerted by a gas on the walls of its container.The absolute temperature of the gas.The amount of gaseous substance (or) the number of moles of gas.Therefore, Moles is held constant when working with Boyle's, Charles's, and Gay-Lussac's laws and the correct option is option 2.
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Describe (in words )the relationship between the distance and time2 as the duster accelerated down the slope (with its smooth surface in contact with the truck)
Distance and time have a direct relationship, meaning the value of one directly affects the value of the other.
Time and distance are directly related to one another. Direct relationship means that if one changes, the other changes as well. Conversely, if one changes, the other changes as well.
We can infer that there is a direct relationship between distance and time if it takes more time to travel a distance that is a huge amount, while it takes less time to travel a distance that is short.
When gravity is the only force affecting an object, freefall occurs. The length of time an object spends falling is proportionate to its distance since the acceleration of gravity on Earth is constant.
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which is the best unit of measurement for the volume of a liquid in science?
gallons
liters
feet
meters
Answer - Cubic meter (aka the meters)
Explanation - The SI unit of volume is the cubic meter (m3), which is a derived unit. Liter (L) is a special name for the cubic decimeter (dm3).
What happens to the pressure of an ideal gas if its volume is doubled and its kelvin temperature is halved, assuming the moles of gas does not change?
By ideal gas approximation, the final pressure is 4 times greater than the initial pressure.
We need to know about the ideal gas theory to solve this problem. The ideal gas is assumed that there is no interaction between particles in a gas. It can be determined by the equation
P . V = n . R . T
where P is pressure, V is volume, n is the number of moles gas, R is the ideal gas constant (8.31 J/mol.K) and T is temperature.
From the question above, we know that
V2 = 2V1
T2 = 1/2 . T1
n1 = n2 = n
When the initial and final temperature is the same, we can use the ratio of pressure as
P1 / P2 = (n1 . R . T1 / V1) / (n2 . R . T2 / V2)
P1 / P2 = (n . R . T1 / V1) / (n . R . (1/2.T1) / 2V1)
P1 / P2 = 4
Hence, the final pressure is 4 times greater than the initial pressure.
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