For each of the following strong base solutions, determine [OH−],[H3O+], pH, and pOH

A) 0.11 M NaOH

B) 1.5 x 10^-3 M Ca(OH)2

C) 4.8 x 10^-4 M Sr(OH)2

D) 8.7 x 10^-5 M KOH

Answer:

Option A. 52.00 amu

Explanation:

From the question given above, the following data were obtained:

Isotope A:

Mass of A = 49.946 amu

Abundance (A%) = 4.345%

Isotope B:

Mass of B = 51.941 amu

Abundance (B%) = 83.789%

Isotope C:

Mass of C = 52.941 amu

Abundance (C%) = 9.501%

Isotope D:

Mass of D = 53.939 amu

Abundance (D%) = 2.365%

Average atomic mass =.?

The average atomic mass of the unknown element can be obtained as follow:

Average atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] [(Mass of C × C%)/100] + [(Mass of D × D%)/100]

Average atomic mass = [(49.946 × 4.345)/100] + [(51.941 × 83.789)/100] + [(52.941 × 9.501)/100] + [(53.939 × 2.365)/100]

= 2.170 + 43.521 + 5.029 + 1.276

= 51.996 ≈ 52.00 amu

Therefore, the average atomic mass of the unknown element is 52.00 amu

Answer:

Supercooled

Explanation:

you can cool very pure water well below zero degrees Celsius without it freezing. Water in this condition is called "supercooled".

Answer:

It is supercooled.....

Answer:

maybe sun is the answer

Explanation:

because it is the source of almost every energy of eaeth becoz even we human and other every living organisms cant leave without sun

Answer:

Sun

Explanation:

I just took the quiz

The standard enthalpy change for reaction (3) is 117.1 kJ.

The standard enthalpy change for reaction (3) can be calculated by using the enthalpy changes of reactions (1) and (2) and applying Hess's Law.

To do this, we need to manipulate the given equations so that the desired reaction (3) can be obtained.

First, we reverse reaction (1) to get the formation of C2H4(g) from C2H6(g):

C2H4(g)C2H6(g) ΔH° = -52.3 kJ

Next, we multiply reaction (2) by 2 and reverse it to obtain 2 moles of C2H6(g) reacting to form 3 moles of H2(g):

2C2H6(g)2C(s) + 3H2(g) ΔH° = 169.4 kJ

Now, we add the two modified equations together:

C2H4(g)C2H6(g) ΔH° = -52.3 kJ
2C2H6(g)2C(s) + 3H2(g) ΔH° = 169.4 kJ

When adding these equations, the C2H6(g) on the left side cancels out with the C2H6(g) on the right side, leaving us with the desired reaction (3):

C2H4(g) + H2(g)C2H6(g) ΔH° = -52.3 kJ + 169.4 kJ = 117.1 kJ

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Answer:

blizzard because it is cold and rainy all the time.

Explanation:

Blizzard is a natural disaster that is least likely to occur in Maryland.

Maryland was a home to 7th state in united states. Maryland’s most common natural disasters include :

Maryland has been impacted by several floods. Hurricane season begins one June 1st. Different storms are seen in Maryland.  There are two types of disaster manmade and natural. Floods, volcanoes are natural disasters.

Maryland has vast variety of tropological features which include lakes, rivers, mountains and pine forests. Blizzard is a dangerous weather event, it is a snowfall.

Therefore, Blizzard is a natural disaster that is least likely to occur in Maryland.

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A precipitate is a solid that forms in a solution when two or more chemicals react. The chemicals that make up the precipitate are usually insoluble, which means they cannot be dissolved in the liquid.

The precipitate forms because the chemicals react to form a new compound that is insoluble in the liquid.  Out of the given options, the combination that will produce a precipitate is AgNO3 (aq) and Ca(C2H3O2)2 (aq).

The balanced chemical equation for the reaction between these two compounds is given below: AgNO3(aq) + Ca(C2H3O2)2(aq) → Ag2(C2H3O2)2(s) + Ca(NO3)2(aq) Combining these two compounds, the silver ions from AgNO3 and the acetate ions from Ca(C2H3O2)2 will combine to form the precipitate silver acetate Ag2(C2H3O2)2(s), which is insoluble and thus will be precipitated out of the solution. Therefore, the correct answer is option C: AgNO3 (aq) and Ca(C2H3O2)2 (aq).

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Given that Koxygen (Henry's Law constant) is 1.3 x 10^-3 mol/L atm, we can calculate the mass of oxygen dissolved in grams.

Henry's Law states that the concentration of a gas dissolved in a liquid is directly proportional to the partial pressure of the gas above the liquid. The equation for Henry's Law is C = K * P, where C is the concentration of the gas, K is the Henry's Law constant, and P is the partial pressure of the gas.

First, let's convert the given partial pressures to atm:

Partial pressure of O2 in lungs (P) = 25 mmHg to 40 mmHg

P = 25 mmHg * (1 atm / 760 mmHg) = 0.0329 atm

P = 40 mmHg * (1 atm / 760 mmHg) = 0.0526 atm

Now, we can calculate the concentration of oxygen using Henry's Law:

C = K * P

Concentration of O2 at 25 mmHg:

C1 = (1.3 x 10^-3 mol/L atm) * (0.0329 atm) = 4.267 x 10^-5 mol/L

Concentration of O2 at 40 mmHg:

C2 = (1.3 x 10^-3 mol/L atm) * (0.0526 atm) = 6.838 x 10^-5 mol/L

To calculate the mass of oxygen dissolved, we need to multiply the concentration by the molar mass of oxygen (32 g/mol) and the volume of water (1.0 L):

Mass of oxygen dissolved at 25 mmHg = (4.267 x 10^-5 mol/L) * (32 g/mol) * (1.0 L) = 0.001366 g

Mass of oxygen dissolved at 40 mmHg = (6.838 x 10^-5 mol/L) * (32 g/mol) * (1.0 L) = 0.002188 g

Therefore, the mass of oxygen that can dissolve in 1.0 L of water at 25°C at a partial pressure ranging from 25 mmHg to 40 mmHg is approximately 0.001366 g to 0.002188 g.

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The molar mass of chromium is 51. 966 gmol , the number of atoms of chromium in 125.8 g is 1.46 × 10²⁴ atoms.

Step 1: Find the number of moles of chromium using the formula:

n = m/M. Where,

m = mass of chromium = 125.8 g

M = molar mass of chromium = 51.966 g/mol

n = 125.8 g/51.966 g/mol = 2.42 mol

Step 2: Find the number of atoms of chromium using Avogadro's number (6.022 × 10²³ atoms/mol).

The formula is: Number of atoms = n × N where N is Avogadro's number. Number of atoms of chromium = 2.42 mol × 6.022 × 10²³ atoms/mol = 1.46 × 10²⁴ atoms (Answer).Therefore, the number of atoms of chromium in 125.8 g is 1.46 × 10²⁴ atoms.

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Unopened beer is a homogeneous mixture. A homogeneous mixture, also known as a solution, is a mixture where the components are uniformly distributed throughout the entire mixture.

Resulting in a consistent composition and properties. In the case of unopened beer, it is a homogeneous mixture because the water, ethanol, carbon dioxide, and flavoring compounds (such as those from hops and malt) are evenly distributed at the molecular level. This means that any small portion of the beer will have the same composition and taste as any other portion.

The homogeneity of beer is primarily due to the process of brewing, where the ingredients are thoroughly mixed and dissolved in water to create a consistent blend. During fermentation, yeast converts sugars into alcohol and carbon dioxide, contributing to the formation of ethanol and carbon dioxide in the beer. The various flavors from hops, malt, and other ingredients further enhance the complexity of the mixture.

The uniformity of beer is important for ensuring a consistent taste experience for consumers. It allows for the desired balance of flavors and aroma, creating the characteristic profile of different beer styles. Additionally, the uniformity of the mixture facilitates quality control during production, as brewers can sample and analyze any portion of the beer to assess its attributes. Overall, the homogeneous nature of unopened beer as a mixture is crucial for its enjoyment and the ability to reproduce its desirable characteristics batch after batch.

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Answer:

lilpeep66661

Explanation:

add me i play

The mass of the trifluoroacetic acid sample is approximately 205.2 g.

Given, a sample of trifluoroacetic acid, C2HF3O2, contains 51.3 g of carbon.To find: The mass of the trifluoroacetic acid sample.Step-by-step explanation:To calculate the mass of the trifluoroacetic acid sample, we need to find the molecular mass of the compound.To find the molecular mass of trifluoroacetic acid, we need to add the atomic masses of all the atoms present in the molecule.C2HF3O2Number of carbon atoms (C) in the compound = 2Number of hydrogen atoms (H) in the compound = 3 Number of fluorine atoms (F) in the compound = 3Number of oxygen atoms (O) in the compound = 2Atomic masses:C = 12.01 g/molH = 1.008 g/molF = 18.998 g/molO = 15.999 g/molNow, let's calculate the molecular mass of trifluoroacetic acid.Molecular mass of trifluoroacetic acid= (2 × 12.01) + (3 × 1.008) + (3 × 18.998) + (2 × 15.999)= 96.02 g/molThus, the molecular mass of trifluoroacetic acid is 96.02 g/mol.Now, we have to find the mass of the sample containing 51.3 g of carbon.Carbon content in the compound = (2 × 12.01)/96.02= 0.250 g/gmoleMass of the sample containing 51.3 g of carbon= (51.3/0.250) gmole= 205.2 g (approx.).

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The ionic charges of the ions formed by magnesium and oxygen are Mg²⁺ and O²⁻, respectively. When these ions combine, they form a neutral compound.

To determine the empirical formula of the compound, we need to find the lowest whole number ratio of Mg²⁺ ions to O²⁻ ions that results in a neutral compound. This can be done by finding the least common multiple of the two charges.The least common multiple of 2 and 2 is 2. Therefore, the empirical formula for the compound formed between magnesium and oxygen is MgO.
Similarly, the ionic charges of the ions formed by lead and iodine are Pb²⁺ and I⁻, respectively. The least common multiple of 2 and 1 is 2. Therefore, the empirical formula for the compound formed between lead and iodine is PbI₂.
The experimental results would match the predictions if the empirical formulas obtained from the charges of the ions formed by the elements match the formulas of the actual compounds formed between the elements.

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The freezing point of the solution is -11.8 °C.

The boiling point of the solution is 103.31 °C.

To determine the freezing point of the solution, we can use the equation:

ΔTf = Kf * m

where:

ΔTf is the freezing point depression,

Kf is the cryoscopic constant (for water, Kf = 1.86 °C/m),

m is the molality of the solution (moles of solute per kilogram of solvent).

First, let's calculate the molality (m) of the solution:

Molar mass of ethylene glycol (C2H6O2):

C = 12.01 g/mol

H = 1.01 g/mol (x 6) = 6.06 g/mol

O = 16.00 g/mol (x 2) = 32.00 g/mol

Total molar mass = 12.01 g/mol + 6.06 g/mol + 32.00 g/mol = 50.07 g/mol

Number of moles of ethylene glycol (C2H6O2) = mass / molar mass

Number of moles = 30.8 g / 50.07 g/mol = 0.615 mol

Mass of water = volume x density = 96.6 mL x 1.00 g/mL = 96.6 g

Now, let's calculate the molality:

Molality (m) = moles of solute / mass of solvent (in kg)

Molality = 0.615 mol / 0.0966 kg = 6.36 mol/kg

Now we can calculate the freezing point depression (ΔTf):

ΔTf = Kf * m

ΔTf = 1.86 °C/m * 6.36 mol/kg = 11.8 °C

To find the freezing point of the solution, subtract the freezing point depression from the freezing point of pure water (0 °C):

Freezing point = 0 °C - 11.8 °C = -11.8 °C

To determine the boiling point of the solution, we can use the equation:

ΔTb = Kb * m

where:

ΔTb is the boiling point elevation,

Kb is the ebullioscopic constant (for water, Kb = 0.52 °C/m),

m is the molality of the solution (same value as calculated before: 6.36 mol/kg).

ΔTb = 0.52 °C/m * 6.36 mol/kg = 3.31 °C

To find the boiling point of the solution, add the boiling point elevation to the boiling point of pure water (100 °C):

Boiling point = 100 °C + 3.31 °C = 103.31 °C

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Answer:

0.5

Explanation:

Answer:

《HOPE IT WILL HELP YOU 》

Explanation:

2 Atom of Hydrogen are present in 2 (NaHCO3)

The atoms of hydrogen are present in 2(NaHCO3) is 2 atoms.

Atoms are defined as a material component that specifically characterizes a chemical element. An atom is made up of a core nucleus and one or more negatively charged electrons that orbit it. The positively charged, comparatively hefty protons and neutrons that make up the nucleus may be present. The typical radius of an atom is 0.1 nm. An average pin head may hold about 5 million hydrogen atoms.

Its chemical formula is NaHCO3. Its formula consists of one sodium (Na) atom, one hydrogen (H) atom, one carbon (C) atom and three oxygen (O) atoms. But in this it is given as 2(NaHCO3) so it contain two sodium atom, two hydrogen atom, two carbon atom and six oxygen atom.

Thus, the atoms of hydrogen are present in 2(NaHCO3) is 2 atoms.

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At 25 degrees Celsius, the osmotic pressure across a semipermeable membrane separating pure water from seawater, with a total ion concentration of 1.177 M, is approximately 63.4 atm.

To calculate the osmotic pressure across a semipermeable membrane separating pure water from seawater, we can use the ideal gas law in the form of the van't Hoff equation for osmotic pressure.

The van't Hoff equation for osmotic pressure is given by:

π = i * M * R * T

Where:

π is the osmotic pressure

i is the van't Hoff factor (number of particles formed per solute particle)

M is the molarity of the solution

R is the ideal gas constant (0.0821 L·atm/(mol·K))

T is the temperature in Kelvin

For seawater, the total concentration of all the ions is given as 1.177 M. However, since the osmotic pressure calculation requires the molarity of the solute particles, we need to determine the effective molarity by considering the van't Hoff factor.

The van't Hoff factor for seawater varies depending on the specific ions present. As a general approximation, we can assume an average van't Hoff factor of 2 for ionic compounds, as many ions dissociate into two particles in water.

Given:

M = 1.177 M

R = 0.0821 L·atm/(mol·K)

T = 25 + 273.15 K (converting from Celsius to Kelvin)

Substituting the values into the van't Hoff equation:

π = 2 * 1.177 M * 0.0821 L·atm/(mol·K) * (25 + 273.15) K

π ≈ 63.4 atm

Therefore, the osmotic pressure across the semipermeable membrane separating pure water from seawater at 25 degrees Celsius is approximately 63.4 atm.

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Explanation:

The kinetic energy of an object given it's mass and velocity can be found by using the formula

where

m is the mass

v is the velocity

Hope this helps you

Answer:

it's physical change because none of the components of the bar of solid have been tampered with so solid to liquid is physical change

The melting of  solid gold into liquid and then being poured into molds is a physical change.

Physical changes are the type of changes which affect the state of a chemical substance,thereby only bringing about physical change but it does not change it's chemical composition.

They are used to separate mixtures into their components. It involves change in physical properties.A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not change.

Melting is a physical change  because physical changes occur to solid which are change in shape,size,density ,volume as well as structure.During melting of gold no  chemical change or reaction takes place.

As the solid gold is melted to make coins and as melting is a physical change which just changes the state of substance.    

Therefore,the melting of gold  to make coins is a physical change.    

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The energy required to break one mole of hydrogen-hydrogen bonds in H2 is 436 kJ/mol divided by Avogadro's number, which is equal to 7.246 x 10-19 J/bond. To calculate the longest wavelength of light, we substitute the values in the formula as given below:  = (6.626 x 10-34 J.s) x (2.998 x 108 m/s) / (7.246 x 10-19 J/bond).The longest wavelength of light with sufficient energy to break a single hydrogen-hydrogen bond is 2.742 x 10-7 m.

To calculate the longest wavelength of light, we will use the formula: Energy of a photon (E) = Planck's constant (h) x speed of light (c) / wavelength (λ)Rearranging the above formula we can get,

λ = hc/E where λ is the wavelength, h is Planck's constant, c is the speed of light, and E is the energy of the photon.

The energy required to break one mole of hydrogen-hydrogen bonds in H2 is 436 kJ/mol.

The energy required to break one bond in H2 is 436 kJ/mol divided by Avogadro's number (6.022 x 1023), which is equal to 7.246 x 10-19 J/bond.

So the energy of the photon required to break a single hydrogen-hydrogen bond is 7.246 x 10-19 J/bond.To calculate the wavelength of this photon, we need to substitute the values in the formula as given below:

λ = (6.626 x 10-34 J.s) x (2.998 x 108 m/s) / (7.246 x 10-19 J/bond)λ

= 2.742 x 10-7 m

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Answer:

-2 charge

Explanation:

Each electron has a -1 charge so assuming at the was originally neutral, 2 more electrons would give it a -2 charge.

Answer:

C) A mixture

Explanation:

Bronze is a mixture of copper and tin. Water is a compound of the elements hydrogen and oxygen.

Hope this helps!

When electrons reach the filament of an incandescent lightbulb, they transfer their kinetic energy to the atoms in the filament, causing them to become excited.

When electrons reach the lightbulb, several processes occur that result in the emission of light. The specific behavior of electrons in a lightbulb depends on the type of lightbulb, such as incandescent, fluorescent, or LED. In this response, we will focus on the incandescent lightbulb, which is a commonly used type.

In an incandescent lightbulb, the filament is made of a material such as tungsten. When an electric current flows through the filament, the following happens:

Electron Flow: The electric current, which is the flow of electrons, passes through the filament. The filament resists the flow of electrons, causing them to collide with the atoms of the filament material.

Heating and Excitation: The collisions between electrons and atoms in the filament result in energy transfer. The kinetic energy of the electrons is converted into thermal energy, which heats up the filament. As the temperature increases, the atoms in the filament become excited, moving to higher energy levels.

Radiative Decay: As the excited atoms in the filament return to their ground state, they release the excess energy in the form of light. This process is known as radiative decay. The released energy corresponds to specific wavelengths or colors of light. The emitted light consists of a broad spectrum of wavelengths, ranging from infrared to visible light.

Incandescent Light Emission: The emitted light is a result of the thermal radiation from the heated filament. The energy of the emitted photons determines the color of the light. For example, a higher filament temperature emits more energy, resulting in a brighter and "warmer" light, while a lower temperature emits less energy, producing a dimmer and "cooler" light.

It's important to note that in incandescent bulbs, a significant portion of the energy is also emitted as heat, making them relatively inefficient compared to other lighting technologies.

In summary, as the excited atoms return to their ground state, they emit light through radiative decay. This process of electron excitation and subsequent light emission creates the illumination we observe from the lightbulb.

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The percent ionization of a 0.250 M solution of HC2H3O2 is approximately 1.3%.

To find the percent ionization, we need to calculate the concentration of the dissociated ions and compare it to the initial concentration of the acid. In this case, HC2H3O2 (acetic acid) partially dissociates into H+ and C2H3O2- ions.

Given:

Initial concentration of HC2H3O2 = 0.250 M

Ka (acid dissociation constant) = 1.8×10^(-5)

Let x be the concentration of H+ ions and C2H3O2- ions formed upon dissociation.

The equilibrium expression for the dissociation of acetic acid is:

Ka = [H+][C2H3O2-] / [HC2H3O2]

Assuming x is small compared to the initial concentration of HC2H3O2, we can approximate it as x.

Ka = x * x / (0.250 - x)

Since Ka is very small compared to 0.250, we can simplify the equation to:

Ka ≈ x^2 / 0.250

Solving this quadratic equation, we find:

x ≈ √(Ka * 0.250)

Substituting the given values:

x ≈ √(1.8×10^(-5) * 0.250)

x ≈ 7.07×10^(-3) M

The percent ionization is given by:

Percent ionization = (concentration of dissociated ions / initial concentration of acid) * 100

Percent ionization = (7.07×10^(-3) M / 0.250 M) * 100

Percent ionization ≈ 2.83%

Rounded to two significant figures, the percent ionization of the 0.250 M solution of HC2H3O2 is approximately 1.3%.

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Answer:

protons only

Explanation:

proton is present in the nucleus of atom as sub atomic particle ..

proton has + charge in the it's top as p+..

Answer: B. Protons Only

Reason: I just took the Pretest!!!!!!

Atomic mass is the mass of an atom of a chemical element. It is given as the sum of the number of protons and neutrons in the nucleus of an atom. The correct answer to the question is option A, i.e., 106.803 amu.

The atomic mass of an element is determined by the relative abundance of its isotopes. An isotope is an element that has a different number of neutrons than protons. The atomic mass of silver is given as 107.868 amu. Silver has two isotopes - Ag-107 and Ag-109 - with atomic masses of 106.905 amu and 108.905 amu, respectively. Ag-109 has an abundance of 48.16%. Therefore, the percentage abundance of the other isotope is 100% - 48.16% = 51.84%.Let X be the atomic mass of the other isotope. Therefore, the average atomic mass of silver can be written as:

(106.905 × 0.5184) + (X × 0.4816)

= 107.868

Solving the above equation for X, we get:

X = (107.868 - 55.46) / 0.4816

= 52.408 / 0.4816

= 108.7 amu (approx.)

Therefore, the atomic mass of the other isotope is 106.905 amu.

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Given data: Volume of radioactive neon-19 = 5.0 LTime interval = 103.2 sTo calculate: Percentage of the original radioactive neon-19 that will remain after that time.

Radioactive decay of Neon-19 follows the first-order kinetics, which is given by the equation N = N₀e^(-λt)

where N₀ is the initial amount of the radioactive sample, N is the amount of the radioactive sample left after time t, λ is the decay constant of the radioactive sample and t is the time taken.

The half-life of the neon-19 is given by the formula,

ln(2) / λ = T₁/₂

It is given that volume of neon-19 is 5.0 L.

The total amount of neon-19 in the container can be calculated by using the formula,

M = ρ × V

where M is the mass, ρ is the density and V is the volume of neon-19.

The atomic mass of Neon is 20.1797 g/mol and the natural abundance of Ne-19 is 9.23 %.

The molar mass of neon-19 can be calculated as follows,

Molar mass of Ne-19 = (0.0923 × 19) + (0.9077 × 20.1797)

Molar mass of Ne-19 = 18.4924 + 18.3425

Molar mass of Ne-19 = 36.835 g/molDensity of Ne-19 is 0.900 g/L.M = 0.900 × 5.0M = 4.50 g

Now, the initial number of moles of Ne-19 can be calculated using the formula,

n = M / M

Molar mass of Ne-19 = 36.835 g/moln = 4.50 / 36.835n = 0.12225 mol

Now, we need to calculate the decay constant (λ) of the Neon-19 using the half-life value.

The half-life of the Neon-19 is 17.22 s.ln(2) / T₁/₂ = λln(2) / 17.22

= λλ = 0.0402624 s⁻¹

Now, we can calculate the amount of Neon-19 after 103.2 s using the equation,N = N₀e^(-λt)N

= 0.12225 × e^(-0.0402624 × 103.2)N

= 0.08579 mol

The final amount of Neon-19 is 0.08579 mol.

The percentage of the original radioactive Neon-19 that will remain after 103.2 seconds is calculated as follows, Percentage of original sample remaining

= (Final amount / Initial amount) × 100Percentage of original sample remaining

= (0.08579 / 0.12225) × 100Percentage of original sample remaining

= 70.1506 %.

When a radioactive sample undergoes radioactive decay, the number of radioactive nuclei in the sample decreases with time.

The rate of decrease of the number of radioactive nuclei is proportional to the number of radioactive nuclei present in the sample at that time. This type of decay is called exponential decay. The decay constant is a measure of the probability that a given nucleus will decay per unit time. The decay constant is a characteristic property of the radioactive material and is independent of the number of radioactive nuclei present in the sample.The half-life of a radioactive substance is the time taken for half of the original number of radioactive nuclei present in the sample to decay. The half-life of a radioactive material is also a characteristic property of the material and is independent of the initial number of radioactive nuclei present in the sample. The half-life is usually denoted by T₁/₂.

When the number of radioactive nuclei present in the sample becomes very small, the rate of decrease of the number of radioactive nuclei becomes very slow. At this stage, the radioactive decay can be ignored and the sample is considered to be stable. The time taken for the number of radioactive nuclei to decrease to this level is usually taken as seven times the half-life.The percentage of the original radioactive sample that remains after a given time is calculated by dividing the amount of the radioactive sample left after the given time by the original amount of the sample and then multiplying the result by 100. The percentage of the original sample remaining is a measure of the activity of the radioactive sample.

The percentage of the original radioactive Ne-19 that will remain after 103.2 seconds is 70.1506 %.

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The reaction in the coffee-cup calorimeter is an exothermic reaction.  The water lost a heat of 2799.4 J of heat during the reaction

a. The reaction between HCl and water in the coffee-cup calorimeter is exothermic. This can be determined by comparing the initial and final temperatures of the substances.

The initial temperature of the HCl was higher than the initial temperature of water, indicating that the HCl had more thermal energy.

However, after the reaction, the final temperature of both substances decreased, which means heat was released into the surroundings. Therefore, the reaction is exothermic.

b. To calculate the heat gained or lost by the water, we can use the equation q = mcΔT, where q represents the heat, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.

The mass of water is given as 100.0 g, and the specific heat capacity of water is approximately 4.18 J/g·°C. The change in temperature is calculated as (31.3 - 24.6) = 6.7 °C.

Plugging these values into the equation, we get q = (100.0 g)(4.18 J/g·°C)(6.7 °C) = 2799.4 J. Therefore, the water lost 2799.4 J of heat.

In the second part of the question, the total pressure in the 20.0 L flask can be calculated using the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant (0.0821 L·atm/mol·K), and T is the temperature in Kelvin.

The total number of moles of gas in the flask is given as 0.400 mol of H2(g) and 0.215 mol of N2(g), which sums up to 0.615 mol. The temperature is given as 293.15 K.

Plugging these values into the equation, we get (P)(20.0) = (0.615)(0.0821)(293.15), which simplifies to P = 0.765 atm. Therefore, the total pressure in the flask is 0.765 atm.

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Answer:

atomic structure

Explanation:

Its pretty obvious. Nothing here can test atomic structure. You can test melting point, with a hot plate. You can test the ability to dissolve something with the container of water. You can test brittleness  with the hammer.

Answer:

Atomic Structure

Explanation:

This chemical element has Solids,Gasses, Liquids, and Plasma that are composed from ionized atoms.

Answer:

Physical weathering is caused by purely mechanical changes to the rock, while chemical weathering is caused by chemical reactions.

Explanation:

Chemical weathering happens when the chemicals get diluted and dissolved in water and seep and percolate down the rock surfaces.

Physical weathering happens when rocks are fragmented into minor fragments while ensuring no alterations in their chemical makeup. The main causes behind physical weathering include spontaneous fluctuations in temperature like too high or too low heat or cold