a 7.300 gram sample of aluminum combined quantitatively with some selenium to form a definite compound. the compound weighed 39.35 grams. what is the empirical formula for this compound?

Mass percentage of potassium bromide KBr is 40.0% and the mole fraction of potassium bromide KBr is 0.0915.

The ratio of the mass of the solute contained in a solution to the mass of the solution as a whole is known as the mass percent. When the mass of the solute and the volume of the solution are supplied, the mass/volume percent is employed to indicate the  Mole fraction concentration of the solution. Mole fraction is the ratio of the moles of one component to the total moles that represent all the components in a solution or other combination.

Brief explanation of solution :-

Molarity of KBr solution = 4.60 mol/L

Density of solution d= 1.37 g/mL

Molar mass of KBr=119.002 g/mol

a) Mass percentage of KBr ,(%):

We have formula that M = mxdx10/MW

Here, m is mass of KBr and MW is molar mass of KBr.

M is molarity of solution

Then, m= MXMW/dx10

             = 4.60×119.002 /1.37×10

             =39.95 or 40.0

mass percentage of KBr is 40.0%.

b) Mole fraction of KBr in solution:

Weight of solution, w = dxV

                                   =1.37g/mL *1000mL

                                   =1370g

So, mass of water, [tex]W_{H2O}[/tex] = 1370-(4.60x119.002)

                                          =1370-547.409

                                          = 822.59g

No. of moles of water = mass of water / MW. of water

                                    = 822.59g/18.02 g/mol

                                    =45.65mol

Now, the mole fraction of KBr (solute) is

                                    квт    = No. of moles of KBr / Total no. of moles in solution

                                         = 4.60 mol (4.60+45.65)mol =0.0915  

Mole fraction of KBr= 0.0915

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When a nucleus of 235U undergoes fission, it breaks into two smaller, more tightly bound fragments. The binding energy per nucleon for 235U  is 7.59 MeV/nucleon and for the fission product 137Cs is  8.39 MeV/nucleon.

What is nucleons ?

Nucleons is a term in chemistry that is used designate both protons and nucleus. The atomic nucleus holds them with a very strong force.

1) m_proton + m_netron + m_electron - m_U

= 92*1.007276466812 + 92*5.4857990943e-4 + 143*1.008664916 - (235.0439299)

= 1.9151 u

= 931.494061 * 1.9151 MeV

= 1784 MeV

=> 1784/235 = 7.59 MeV/nucleon

2) m_proton + m_netron + m_electron - m_Cs

= 55*1.007276466812 + 55*5.4857990943e-4 + 82*1.008664916 - (136.9070895)

= 1.2338 u

= 931.494061 * 1.2338 MeV

= 1149 MeV

=> 1145/137 = 8.39 MeV/nucleon

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Answer:

√K = [.08-2x]/[.1+x]

Explanation:

As instructed by the question asker, I am putting this answer down. Hopefully it is correct (fingers crossed).

The density of the given metal is 19.4g/cm³ which is calculated using the density formula.

For the FCC crystal, atoms are in contact along the diagonal of the unit cell.

4r= √2a

where a is  edge length of unit cell and r is  radius of atom.

Substituting values in the above given expression, we get

r= 144pm

Number of the atoms per unit cell (FCC) =4

Mass of 1 unit cell = 197×4=788amu

=1.66×10⁻²⁷  ×788kg=1.30808×10⁻²⁴  kg

Volume of 1 unit cell =(407×10⁻¹² )³ m³

=6.741×10⁻²⁹

 =2.824×10⁻²⁸

Hence the density=  1.30808×10⁻²⁴/ 6.741×10⁻²⁹

=19404.83kg/m³

=19.4g/cm³

The density of the crystal will be 19.4g/cm³

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The molar solubility of Fe(OH)2 at 25 C if K sp of the compound is 7.9 x 10^16 is 5.8 x 10^6 M.

The equilibrium solubility of Fe(OH)2 is as follows:

Fe(OH)2(s) <--------> Fe2+(aq)   +   2OH-(aq)

The equilibrium constant expression for this equilibrium, i.e. Ksp, is as follows.

  Ksp = [Fe2+] [OH-]2

where,

                 [Fe2+] = molar concentration of Fe2+

                  [OH-] = molar concentration of OH-

sp stands for solubility product

The value of Ksp = 7.9×10-16

Now,

Let S represent the molar solubility of Fe(OH)2.

Fe(OH)2 having one Fe2+ and two OH-

So,

                 [Fe2+] = 1S

                 [OH-] = 2S

substitute 1S and 2S in Ksp expression

             Ksp = 1S × (2S)^2

             Ksp = 4S^3

So,

               4S^3 = 7.9 ×10^-16 M3

                 S^3 = 1.975 × 10^-16 M3

                     S = 5.8×10^-6 M

Therefore,

The Molar solubility of Fe(OH)2 = 5.8 ×10-6 M

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Answer:

296,875,000 mol

Explanation:

1mol of SO2 is 64g

1.9×10⁷ kg ----> 1.9×10¹⁰g

1mol ----> 64g

x -----> 1.9×10¹⁰g

x= 1.9×10¹⁰/64 mols

= 296,875,000 mol

The specific heat capacity of water is 1.00 cal/g.°C, 2940 J much heat is required to raise the temperature of 25.0 g water from 22°C to 50.0°C

The specific heat capacity is measured in J/(kg K) or J/(kg °C), and it is the amount of heat (J) absorbed per unit mass (kg) of the material when its temperature rises by 1 K (or 1 °C).

The amount of heat required to increase the temperature of 1 gram of a material by 1 degree Celsius (°C) is known as specific heat. Since water has a higher specific heat than other substances, it requires more energy to raise its temperature.

Given that,

T₁ = 22°C

T₂ = 50.0°C

here

Specific heat capacity of water (Cp) = 1.00 cal/g.°C = 4.2 J/g.°C

Heat required to convert liquid from 22°C to 50.0°C.

Q₁ = m × Cp × (T₂-T₁)

or, Q = 25 g × (4.2 J/g.°C) × (50-22) °C

or, Q = 2940 J

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When pieces of two ionic compounds swap places to create two new compounds, the reaction is known as a double replacement (also known as a double displacement, exchange, or metathesis reaction).

When one reactant is partially replaced by another, the reaction is referred to as a twofold displacement reaction.

The list of double displacement reactions is as follows:

CB + CD + AB = AD

A twofold replacement process replaces the ions in two reactant ionic compounds with the same ions in two new product compounds.

When two reactants transfer cations or anions to create two new products, the reaction is called a double replacement.

Metathesis reactions and double displacement reactions are two other names for double replacement processes.

Examples of double replacement reactions include precipitation, gas production, and neutralization.

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An acid-base titration involves a neutralization reaction

An acid-base titration is a laboratory technique that is used to determine the concentration of an acid or a base in a solution. The basic principle behind this technique is the fact that acid-base reactions are reversible, meaning that an acid and a base can react with each other to form a neutral compound.

In an acid-base titration, a known concentration of a base is added to a solution containing an unknown concentration of an acid. The acid and the base react with each other to form a neutral compound, such as water. By carefully measuring the volume of the titrant that is required to neutralize the acid, the concentration of the acid in the solution can be determined. This process is known as a neutralization reaction.

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The correct response is option C: The attractive interaction between the valence electrons and the atoms' nucleus weakens.

The force of attraction is an attraction that draws the body to it. In nature, there are many alluring forces at work. Among these are gravitational force, magnetic force, electric force, and electrostatic force.

The force of attraction between two bodies, according to Newton's law of gravitation, is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. The gravitational force is always alluring in the natural world.

Give an illustration of an alluring force in nature.

Examples include gravitational force, electric force, electrostatic force, and magnetic force. Since it draws objects regardless of their distance, gravity is a well-known illustration of an attraction force.

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Answer: c

Explanation:

A. 7 x 10^8 mole of H2 requires 8.48 x 10^10 Coulombs of electrical charge, and a voltage of 632.2 V. The minimum electrical energy required to raise the Titanic is 4.02 x 10^13 kW hr, and the minimum cost is $9.2 x 10^7.

1. The amount of H2 gas required to buoy the Titanic is 7 x 10^8 mole.

2. The number of Coulombs of electrical charge required to generate this amount of H2 gas is computed using Faraday's Law:

Q = nF

Where n is the number of moles of H2, F is the Faraday constant (96485 C/mol), and Q is the number of Coulombs.

Therefore, Q = (7 x 10^8) x (96485 C/mol) = 8.48 x 10^10 C.

3. The minimum voltage required to generate H2 and O2 gases is computed using the Nernst Equation:

E = E° - (RT/nF) ln(Q/Q°)

Where E is the voltage, E° is the standard voltage (1.229 V at 300 atm and 25°C), R is the gas constant (8.314 J/molK), T is the temperature (288 K at 2 miles depth), n is the number of moles of H2, F is the Faraday constant (96485 C/mol), Q is the number of Coulombs, and Q° is the standard charge (1 C).

Therefore, E = 1.229 - (8.314 J/molK x 288 K / (7 x 10^8 mol x 96485 C/mol)) ln(8.48 x 10^10 C / 1 C) = 632.2 V.

4. The minimum electrical energy required to raise the Titanic is calculated using the equation:

E = QV

Where E is the electrical energy, Q is the number of Coulombs, and V is the voltage.

Therefore, E = (8.48 x 10^10 C) x (632.2 V) = 4.02 x 10^13 kW hr.

5. The minimum cost of the electrical energy required to generate the necessary H2 gas is calculated using the equation:

Cost = (E x Price) / (1000 x 3600)

Where E is the electrical energy, Price is the cost per kW hr, and 1000 and 3600 are conversion factors.

Therefore, Cost = (4.02 x 10^13 kW hr x $0.23/kW hr) / (1000 kW hr/kW hr x 3600 s/hr) = $9.2 x 10^7.

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Complete question:

Some years ago a unique proposal was made to raise the Titanic. The plan involved placing pontoons within the ship using a surface‐controlled submarine‐type vessel. The pontoons would contain electrodes (cathodes) and would be filled with H2 gas as a result of the electrolysis of water. It has been estimated that it would require about 7 x 10^8 mole of H2 gas to provide the buoyancy to lift the ship

a) How many Coulombs of electrical charge would be required?

b) What is the minimum voltage required to generate H2 and O2 if the pressure on the gases at the depth of the wreckage (2 miles) is 300 atm?

c) What is the minimum electrical energy (in kW hr) required to raise the Titanic by electrolysis?

d) What is the minimum cost of the electrical energy required to generate the necessary H2 gas if the electricity costs $0.23 per kilowatt‐hour (kW hr) to generate at the site?

There are a total of 24 atoms in 3 Na₃PO₄. 9 sodiums, 3 phosphorous and 12 oxygens are there.

Sodium phosphate is an ionic compound formed by the loss of electron from sodium atom to the phosphate group. There are 3 sodium atoms in one sodium phosphate Na₃PO₄. One electrons from each sodium atom donates to the phosphate group.

The number of atoms in a compound are written as the subscripts for each chemical symbol. In Na₃PO₄, there are 3 sodium atoms, one phosphorous and 4 oxygen atoms. Thus, there are total 8 atoms.

In 3 Na₃PO₄, thus, contains 8 × 3 = 24 atom. Hence, the total number of atoms in 3Na₃PO₄ is 24.

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The system goes through a reversible process, but because there is no heat movement, the entropy of the system stays the same. Entropy must rise if the process is irreversible.

In other words, it doesn't go down. Entropy change occurs solely as a result of irreversibilities in the absence of any heat transmission, and its consequence is invariably a rise in entropy. In a process that is only adiabatic, entropy does not remain constant.

In an adiabatic process that is also reversible, entropy doesn't change.

where there is no mass transfer in a close system. Because the process is adiabatic, there is no heat transmission and no entropy change as a result of heat transfer. If the process is likewise reversible, then neither entropy inside the system is generated nor is there any entropy change as a result of entropy formation. Therefore, for an adiabatic process that is also reversible, the entropy change is zero.

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The density of the irregular object, given that it has a mass 42.67 g and it displaces a volume of water equivalent to 12.9 mL is 3.31 g/mL

We know that the density of a substance is defined as mass per unit volume as shown below:

Density = mass / volume

With the above formula, we can obtain the density of the irregular object as illustrated below:

Density = mass / volume

Density of irregular object = 42.67 / 12.9

Density of irregular object = 3.31 g/mL

Thus, from the above calculation, the density of the irregular object is 3.31 g/mL

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Therefore, the solution's needed molarity is:6.01M

Check the table below to understand the computations.

Molarity:

Calculating the concentration of a solute that is present in a certain volume of solution is done using the Molarity (M) or Molar Concentration approach. The unit of measurement for the solute is the mole, whereas the unit of measurement for the solution is the liter. The amount of moles of a solute present in one liter of a solution, or moles per liter of a solution, is consequently defined as molarity, represented by the symbol M.

This is, Molarity=moles/volume

Due to it,

mass KF=78.6 g.

KF moles = mass / molar

                =78.6/58.09

                =1.353mol

volume = 0.225 L from 225 ml.

Using the aforementioned method, we can now get the necessary molarity as,

Molarity=moles/volume

             =1.353/0.225

Molarity=6.01M

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Answer:

Explanation:

Correct option is (D).

When human body bend at the elbow , then there is contraction of biceps.

After this there is relaxation of biceps and on other hand the triceps contracts so that elbow is straightened.

The statement that is true is bending of arms involves the contraction and relaxation of a pair of muscles. The correct option is D.

The process of shortening the sarcomere and, consequently, the whole myocyte during muscle contraction involves the sliding of the thin filaments through the thick filaments.

The tendon transfers the ensuing longitudinal tension from the extracellular matrix (ECM) to the bone. An Action Potential that travels from the nerves to the muscles causes a muscle contraction. The neurological system sends a signal, which triggers the onset of muscle contraction.

The biceps contract whenever the human body bends at the elbow. Following this, the triceps contract while the biceps relax, causing the elbow to straighten.

Therefore, the correct option is D. Bending of arms involves the contraction and relaxation of a pair of muscles.

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It is true that the most common type of regenerated fiber, which is derived from cellulose and is mostly plant in origin, is rayon.

The most widely used type of regenerated fibre is rayon, which is mostly derived from plants and is manufactured from cellulose. Synthetic polymer fibres with a cellulose base are all derived from petroleum. 

Dietary fibres are produced from indigestible plant parts and frequently consist of long, repeated chains of carbohydrates. The majority of fibers come from cereal and grain husks, which contain the insoluble fibers cellulose and lignin. The bulk of plant fibers are made of cellulose, sometimes in combination with other materials like lignin.

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In an at-home lab, the best course of action to take in the event that a chemical gets in your eye is to flush your eye with a clean water source.

An eye wash station is an emergency device used to provide immediate and sustained irrigation to the eyes in the event of a hazardous material splash or other accident involving the eyes. It consists of a bowl or basin of potable water connected to a pressurized water source, often with an adjustable flow-control device. Eye wash stations are designed to allow for the user to tilt their head back and irrigate both eyes at the same time, usually for a period of 15 minutes. This is necessary in order to remove hazardous material from the eye before it can cause damage. Eye wash stations should be installed in areas where hazardous materials are handled, stored, or used, as well as areas where workers may be exposed to hazardous materials. They should also be clearly marked and easily accessible in case of an emergency.

This can be done by holding your eye open and running clean water over it for at least 15 minutes. This will help to flush out the chemical and reduce the risk of eye damage. Additionally, it is important to seek medical attention as soon as possible after flushing your eye to ensure that the chemical did not cause any further damage.

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Answer:

The Pacific ocean

Explanation:

Why because it Causes by the amount of movement of tectonic plates in the area.

Answer:

Fe + 3NaBr FeBr3 + 3No

Explanation:

In a single replacement reaction, a single element is replaced by another element in a compound. In this case, the iron (Fe) atom is replaced by a bromine (Br) atom, forming the compound iron (III) bromide (FeBr3) and sodium (Na) ions.

The other reactions you provided are not single replacement reactions. For example, in the first reaction, Ca(OH)2 and H2SO4 react to form CaSO4 and H2O, but no element is replaced by another element. In the second reaction, CH4 and O2 react to form CO2 and H2O, but again, no element is replaced. In the third reaction, H2O and CO2 react to form H2CO3, a compound known as carbonic acid. This reaction is not a single replacement reaction because no elements are replaced by other elements.

If you placed a magnet in a furnace capable to melting any mineral and turned it to maximum then magnet will lose its magnetic force.

anything that can produce a magnetic field around itself and draw iron with it is a magnet. Every known element and several compounds had undergone magnetism tests by the end of the 19th century, and it was found that each one of them possessed some magnetic properties. The only three elements that exhibit ferromagnetism are iron, nickel, and cobalt. All ferromagnetic materials exhibit hysteresis, a lag in response to shifting forces brought on by energy losses from internal friction. When B is measured for various values of H and the results are graphically displayed, a loop of the kind shown in the accompanying figure is created. A hysteresis loop is what this loop is called.

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When the electrons in an atom transition between energy levels, according to Bohr, an atomic spectrum is produced. When energy is absorbed, the electrons would leap to a greater energy level than they normally would, creating an excited and unstable condition. Electrons ordinarily have the lowest energy attainable.

The characteristic wavelengths of electromagnetic radiation (or a subset of it) that are released or absorbed by a material, atom, or molecule are known as a spectrum.

The term "spectrum" alludes to how various people experience autism in a variety of ways; autism is a condition that is highly diverse. Autism is seen as a spectrum disorder because each autistic person experiences it differently. Some autistic people may require more care than others in order to live the lifestyles they desire.

The sun's spectrum of colors, the rainbow, and a molecule's infrared absorption wavelengths are a few examples of spectra.

Continuous, emission, and absorption spectra are the many types.

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At the equivalence point, the molarities of the two solutions are equal, so the volume of the NaOH required to neutralize the HCl is also 40.0 mL, for the titration.

The concentration of HCl multiplied by the volume of HCl must be equal to the concentration of NaOH multiplied by the volume of NaOH. The concentration of the HCl is 0.120 moles/L and the volume of the sample is 40.0 mL. This means that the concentration of NaOH multiplied by the volume of NaOH must equal 0.120 x 40.0 = 4.8 moles. The concentration of NaOH is also 0.120 moles/L, so the volume of NaOH must be 4.8/0.120 = 40.0 mL. This means that 40.0 mL of 0.120 m NaOH is needed at the equivalence point of the titration to neutralize a 40.0 mL sample of 0.120 m HCl.  To determine the volume of 0.120 m NaOH needed at the equivalence point of a titration, the moles of HCl and NaOH must be equal. This means that the concentration of HCl multiplied by the volume of HCl must be equal to the concentration of NaOH multiplied

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The biogas produced by anaerobic fragmentation has the most content of methane, CO₂, H₂S, and water.

Biogas can be described as a mixture of gases consisting of methane, carbon dioxide, and hydrogen sulfide, formed from raw materials such as agricultural waste, municipal waste, sewage, plant material, green waste, and food waste. Biogas can be described as a renewable energy source.

Biogas can be produced by anaerobic digestion with anaerobic organisms inside an anaerobic digester, bioreactor, or biodigester. Biogas is methane, carbon dioxide, and may have little amounts of hydrogen sulfide, moisture, and siloxanes.

The gases methane and carbon monoxide can be combusted or oxidized with oxygen. This energy release permits biogas to be used as fuel, for any heating purpose, such as cooking. Biogas can be used in a gas engine to transform the energy in the gas into electricity and heat.

In some cases, biogas consists siloxanes. Hydrogen sulfide is corrosive in the biogas stream.

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More material per mole can be found in helium.

The unit of measurement for quantity is the mole. Things react in straightforward mole ratios. However, as balances do not provide readings in moles, you must convert them into grams when comparing the amount of one material to another using moles.

To convert molecular weights to grams, follow these three procedures.

1. Determine the number of moles mentioned in the question.

2. Determine the substance's molar mass.

3. Multiply the two figures.

Avogadro's number of atoms makes up one mole. The amount of a mole can be translated to grams if you know how many there are, and vice versa.

80g/4g/mol helium = 20 Mol

400g/40g/mol of argon = 10 mol

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The right-hand side of the atomic numbers contains nonmetals, which have relatively high electronegativity values and a propensity to gain electrons.

Atoms in molecules are held together by chemical bonds. Electrostatic forces between negative-charged electrons and ionized atomic nuclei produce bonds (the positions of which in space are determined by quantum mechanics).

A chemical bond is the term used to describe the attraction amongst atomic nuclei. To form bonds, atoms exchange or swap their valence electrons. The valence electrons, which make up an atom's lowest energy level, have the capacity to interact chemically. The most straightforward explanation is that atoms are trying to enter the safest (lowest-energy) state they can.

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Atoms with a strong attraction for electrons they share with another atom exhibit high electronegativity.

The tendency of an atom of a certain chemical element to attract shared electrons (or electron density) when forming a chemical bond is known as electronegativity. The atomic number of an atom and the distance of its valence electrons from the charged nucleus both have an effect on how electronegative that atom is.

An atom or substituent group will attract electrons more when the corresponding electronegativity is stronger. In order to define a bond along the continuous scale from covalent to ionic bonding, electronegativity provides a simple method for quantitatively measuring the bond energy as well as the orientation and strength of a bond's chemical polarity.

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