I need help...................... ​

The selenide ion concentration [Se2-] for a 0.300 M H2Se solution with the given stepwise dissociation constants is option D) 3.9 x 10^-16 M.

To find the selenide ion concentration [Se2-], we first need to write out the chemical equation for the dissociation of H2Se:

H2Se ⇌ H+ + HSe-  (Ka1 = 1.3 x 10^-4)
HSe- ⇌ H+ + Se2-  (Ka2 = 1.0 x 10^-11)

At equilibrium, we can use the equilibrium constant expression to relate the concentrations of the species:

Ka1 = [H+][HSe-]/[H2Se]
Ka2 = [H+][Se2-]/[HSe-]

We know the initial concentration of H2Se is 0.300 M, and since the dissociation constants are small, we can assume that the concentration of H+ is negligible compared to the initial concentration of H2Se. Therefore, we can simplify the equilibrium expressions to:

Ka1 = [HSe-]/[H2Se]
Ka2 = [Se2-]/[HSe-]

Using the first equilibrium expression and solving for [HSe-], we get:

[HSe-] = Ka1[H2Se] = (1.3 x 10^-4)(0.300) = 3.9 x 10^-5 M

Now we can use the second equilibrium expression and substitute in the value we just found for [HSe-]:

Ka2 = [Se2-]/[HSe-]
1.0 x 10^-11 = [Se2-]/(3.9 x 10^-5)
[Se2-] = (1.0 x 10^-11)(3.9 x 10^-5) = 3.9 x 10^-16 M

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Answer:

20

Explanation:

Hi there!

We need to find the atomic number of an atom that has 20 protons and 20 neutrons

the atomic number of an atom is equivalent to the amount of protons an atom has, as the number of protons determines what element an atom is.

Since the atom has 20 protons, the atomic number of the said atom is 20

Hope this helps!  

Answer:

Non-polar

Explanation:

Non-polar bonds occur when the electrons in a covalent bond are equally shared between the two atoms.

The indicated bond is most likely non-polar because the two atoms are identical (both carbons). In addition, these two carbons are balanced (their other bonds are identical). This means there is no reason for the electrons in the bond to be pulled in any particular direction.

The balanced equation for the reaction is:

2H2 + O2 -> 2H2O

From the balanced equation, we can see that for every 1 mole of oxygen (O2), we need 2 moles of hydrogen (H2) to react and produce 2 moles of water (H2O).

Given that you start with 6.0 moles of oxygen and 4.0 moles of hydrogen, we need to determine the limiting reactant, which is the reactant that will be completely consumed first and determines the maximum amount of product that can be formed.

To find the limiting reactant, we compare the moles of each reactant to the stoichiometric ratio in the balanced equation.

For oxygen (O2):

Moles of O2 = 6.0 moles

For hydrogen (H2):

Moles of H2 = 4.0 moles

Moles of H2 needed = 2 * Moles of O2 = 2 * 6.0 moles = 12.0 moles

Since we have 4.0 moles of hydrogen, which is less than the required 12.0 moles, hydrogen is the limiting reactant.

The balanced equation tells us that 2 moles of water are formed for every 2 moles of hydrogen. Therefore, the number of moles of water produced will be equal to the number of moles of hydrogen.

Moles of water produced = 4.0 moles

Therefore, you will produce 4.0 moles of water.

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The volume occupied at STP by the given mixture of gases is approximately 67.16 L.

To determine the volume occupied by a mixture of gases at STP (Standard Temperature and Pressure), we need to use the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.

At STP, the temperature is 273.15 K and the pressure is 1 atm. The ideal gas constant is 0.08206 L·atm/mol·K.

First, we need to find the number of moles of each gas using its mass and molar mass.

For helium (He), the molar mass is 4.00 g/mol, so the number of moles is:

n(He) = 4.00 g / 4.00 g/mol = 1.00 mol

For hydrogen (H2), the molar mass is 2.02 g/mol, so the number of moles is:

n(H2) = 2.00 g / 2.02 g/mol = 0.9901 mol

For oxygen (O2), the molar mass is 32.00 g/mol, so the number of moles is:

n(O2) = 32.0 g / 32.00 g/mol = 1.00 mol

The total number of moles is:

n(total) = n(He) + n(H2) + n(O2) = 1.00 mol + 0.9901 mol + 1.00 mol = 2.9901 mol

Now, we can use the ideal gas law to find the volume of the gas mixture:

V = nRT/P = (2.9901 mol)(0.08206 L·atm/mol·K)(273.15 K)/(1 atm) = 67.16 L

Therefore, the volume occupied at STP by the given mixture of gases is approximately 67.16 L.

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Some of the acids and bases included in the Arrhenius theory are not acids and bases according to the Bronsted-Lowry theory. The statement is true.

The Arrhenius theory defines an acid as a substance that produces hydrogen ions (H+) in water, and a base as a substance that produces hydroxide ions (OH-) in water. However, according to the Bronsted-Lowry theory, an acid is a substance that donates a proton (H+) to another substance, while a base is a substance that accepts a proton. Therefore, some substances that may be considered acids or bases according to the Arrhenius theory may not fit the definition of an acid or base according to the Bronsted-Lowry theory.

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The lewis structure for these anions are-

a fairly straightforward manner to visualize a molecule's valence shell electrons is through a Lewis structure. It gives insight into the pairing and association of the electrons surrounding every atom in the molecule.

every electron inside the Lewis dot structure can be represented via a dot, and a line connecting the dots is drawn to shape an electron bond.

simplest the valence electrons are taken under consideration whilst sketching the Lewis dot shape, ignoring the electrons that don't belong to the outermost shell.

The Lewis shape is the most effective and maximum constrained speculation; it does no longer describe how bonds are created or how electrons are disbursed most of the atoms. And that is visible as the essential constraint at the Lewis shape.

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Answer:

An indication of calories consumed during anaerobic energy production

Explanation:

RER stands for respiratory exchange ratio, which is the ratio of the volume of carbon dioxide, CO₂, produced to the volume of oxygen, O₂ used in metabolism. RER is used in determining the respiratory quotient during aerobic exercise and rest, from which it can be determined if carbohydrate or fat is the source of fuel consumed in the production of energy for the body through metabolism

Therefore, the answer that is not correct is an indication of calories consumed during anaerobic energy production

Answer:Uranium

80 years

To make that nuclear reaction that makes that heat, those uranium pellets are the fuel. And just like any fuel, it gets used up eventually. Your 12-foot-long fuel rod full of those uranium pellet, lasts about six years in a reactor, until the fission process uses that uranium fuel up.

Transuranic wastes, sometimes called TRU, account for most of the radioactive hazard remaining in high-level waste after 1,000 years. Radioactive isotopes eventually decay, or disintegrate, to harmless materials. Some isotopes decay in hours or even minutes, but others decay very slowly.

Explanation:

Hope this helps

The smallest compound that does not have appreciable torsional, twisting, or dihedral strain is Ethane. Ethane is a hydrocarbon with the formula C2H6. It consists of two carbon atoms and six hydrogen atoms.

The smallest compound that does not have appreciable torsional, twisting, or dihedral strain is Ethane. Ethane is a hydrocarbon with the formula C2H6. It consists of two carbon atoms and six hydrogen atoms. The carbon atoms are bonded together by a single covalent bond, and each carbon atom is also bonded to three hydrogen atoms.Ethane is a straight-chain alkane with a molecular weight of 30.07 g/mol. It is the simplest hydrocarbon compound that has no significant torsional or dihedral strain. Its carbon-carbon bond angle is 109.5 degrees, which minimizes torsional strain. Ethane is used as a fuel in some industrial processes. It is also used as a refrigerant and a feedstock for the production of chemicals.

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The complete Lewis structure of Lorazepam has 6 lone pairs.

Lewis structures, also known as Lewis dot formulas, electron dot structures, or Lewis electron dot structures, are diagrams that depict the interactions between the atoms in a molecule as well as any lone pairs of electrons that may be present.

Lorazepam is a medication used to treat insomnia and anxiety. The time it takes for lorazepam to start working can vary based on the form it is taken in. Specifically, there are a total of 6 lone pairs in the molecule, with two on each of the oxygen atoms and one on each of the nitrogen atoms.

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Answer:

2K + 2H2O → H2 + 2KOH

Explanation:

Find how many atoms you have on both sides then add 2 to both sides.

Reactant:       Products:

K: 1+1=2                K: 1+1=2

H: 2+2=4             H: 3+1=4

O: 1+1=2                O: 1+1=2

Therefore it is balanced. Hope this helps

The distance between the earth and star = 8 ✕ (9.46 ✕ 1012) = 7.6 ✕ 1013 km.

What is exoplanet?

Every planet in our solar system orbits the Sun. Planets known as exoplanets orbit other stars. It is quite challenging to directly observe exoplanets with telescopes. They are hidden by the bright light from the stars they orbit.

It is challenging to give distances in kilometers for many celestial objects since they are so far away from the earth, such as galaxies or stars.

How far light may travel in a year is measured in large units called light-years. The vast distances are therefore expressed in terms of light-years.

9.46 x 1012 kilometres make up a light year.

In other words, if a star is eight light-years away, light would travel that distance in eight years. This is how the distance between a star and the earth is calculated.

Therefore, the distance between the earth and the star is 8 (9.46 1012) = 7.6 1013 kilometers.

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A germinating seed is one from which a plant has started to grow. A non-germinating seed is usually dry, and a new plant has not yet emerged. The germinating corn seed consumed more oxygen than the non-germinating corn seed. This statement is true.  Therefore, option A is correct.

A dry seed starts to absorb water through its seed coat when it comes into touch with damp soil or growing medium. The seed swells and the seed coat splits open as it absorbs more water. Small shoots and roots make up the embryo inside the seed. First to appear from the seed is the root.

The prerequisites for seed germination include oxygen, water, temperature, and, only for particular seeds, light. The sprouting of seeds is impacted when one or more of these are missing. Similar internal elements that impact this process include seed viability, dormancy, and embryonic maturity.

Thus, option A is correct.

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Answer:

maybe C?

Explanation:

srry if wrong

hope it helps

Answer: C.

Explanation:

A. Is out because we know that it can melt iron and nickel B. Is out because metal is most definitely meltable

And for D. Between 8,132° and 9,932° Fahrenheit Is the temperature of the outer core

To determine how many moles of oxygen can be produced from 25 grams of potassium chlorate, we first need to calculate the number of moles of potassium chlorate in 25 grams.

The molar mass of potassium chlorate (KClO3) is 122.55 g/mol. Therefore, the number of moles of KClO3 in 25 grams is:

25 g / 122.55 g/mol = 0.204 moles of KClO3

Next, we can use the stoichiometry of the chemical equation to determine the number of moles of oxygen produced. According to the balanced equation, for every 1 mole of KClO3, 3 moles of oxygen are produced. Therefore, the number of moles of oxygen produced from 0.204 moles of KClO3 is:

0.204 moles KClO3 x 3 moles O2 / 1 mole KClO3 = 0.612 moles O2

Therefore, 25 grams of potassium chlorate can produce 0.612 moles of oxygen.

The volume of carbon dioxide produced when 10.0 L of oxygen is consumed is 6.67 L of CO2 (rounded to two decimal places).

Given balanced equation: C2H4(g) + 3 O2(g) → 2 CO2(g) + 2 H2O(g)The molar volume of all gases at standard temperature and pressure is 22.4 L/mol.Using the balanced equation, we can find the ratio of the volume of oxygen used to carbon dioxide produced.C2H4(g) + 3 O2(g) → 2 CO2(g) + 2 H2O(g)3 moles of O2 produce 2 moles of CO2So, 1 mole of O2 produces (2/3) moles of CO2 or 1 mole of CO2 produces (3/2) moles of O2.

To find the volume of carbon dioxide produced when 10.0 L of oxygen is consumed, we need to use the mole ratio:3 mol O2 → 2 mol CO22/3 mol CO2 is produced by 3 mol O210.0 L of O2 is consumed, which is equal to 10.0/22.4 = 0.4464 moles of O2Thus, using the mole ratio:0.4464 mol O2 × (2/3) mol CO2/1 mol O2 = 0.2976 mol CO2The volume of 0.2976 mol CO2 is:0.2976 mol CO2 × 22.4 L/mol = 6.67 L of CO2 (rounded to two decimal places).

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Answer:

Glasses or contact lenses correct vision because they allow the eye to focus light in the right spot on the retina the spot that produces the clearest image. Because everyone's eyes are different, a pair of glasses that makes one person see wonderfully may look terribly blurry to someone else.

Nearsighted- unable to see things clearly unless they are relatively close to the eyes, owing to the focusing of rays of light by the eye at a point in front of the retina; myopic.

Farsighted- a common vision condition in which you can see distant objects clearly, but objects nearby may be blurry. The degree of your farsightedness influences your focusing ability.

Explanation:

I hope that makes sense

In summary, option A - Ag(s) + 1/2 Br2 → AgBr(s), ΔG = 96.9 kJ/mol, would be coupled with the given reaction to produce silver.

The reaction that would couple with the given reaction to produce silver is option A - Ag(s) + 1/2 Br2 → AgBr(s), ΔG = 96.9 kJ/mol.

This is because the ΔG value for this reaction is positive and greater than the ΔG value for the given reaction, which is also positive. According to the law of thermodynamics, for two reactions to be coupled, the ΔG value for the overall reaction should be negative. This means that the negative ΔG value for one reaction should be greater than the positive ΔG value for the other reaction.

In the given options, option A has the highest positive ΔG value, which makes it suitable to be coupled with the given reaction. The overall reaction would be:

Ag2O(s) + 1/2 Br2 + heat → 2 AgBr(s) + 1/2 O2

This reaction has a negative overall ΔG value, indicating that it is thermodynamically favorable.

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Answer: 392.71 g of O2 would be necessary to produce 221.3g of H2O

Explanation:

The question requires us to calculate the mass of oxygen gas (O2) necessary to produce 221.3g of H2O, given the following balanced equation:

The problem presented can be classified as a mass to mass stoichiometry problem. To solve it, we'll need to follow the steps:

mass of H2O → moles of H2O → moles of O2 → mass of O2

First, let's determine the number of moles of H2O contained in 221.3g of it, knowing that the molar mass of H2O is 18.02g/mol:

(where n is the number of moles, m is the mass of the sample and MM corresponds to the molar mass of the compound)

Therefore, 12.28 moles of H2O need to be produced in the reaction.

Next, let's determine the number of moles of O2 necessary to produce 12.28 moles of H2O. According to the balanced chemical equation, 6 moles of O2 are necessary to produce 6 moles of H2O:

6 mol H2O ------------------- 6 mol O2

12.28 mol H2O ------------- x

Solving for x, we have that 12.28 moles of O2 would be necessary to produce 12.28 moles of H2O.

At last, we need to convert the calculated number of moles of O2 to its correspondent mass, in grams. Knowing that the molar mass of O2 is 31.98g/mol, we can calculate the mass of O2 as:

Therefore, 392.71 g of O2 would be necessary to produce 221.3g of H2O.

Answer:

Sulphate ion

Explanation:

Zinc will undergoes oxidation. Zn2+ - - > Zn + 2e-

Copper will undergoes reduction. Cu2+ + 2e- - - > Cu

Once the boiling point of a solution is reached, any additional heat added will cause the liquid to undergo a phase change from liquid to gas without increasing the temperature.

When a solution reaches its boiling point, it means that the liquid has absorbed enough heat energy to overcome the intermolecular forces holding the molecules together, allowing them to escape as gas. At this point, the temperature of the solution remains constant until all the liquid has evaporated.

Any additional heat energy added to the system will be used solely for the phase change process, converting the remaining liquid into gas rather than increasing the temperature.

This is because the heat energy is being used to break the intermolecular forces and transition the liquid molecules into the gas phase, rather than raising the average kinetic energy (temperature) of the molecules. Once all the liquid has evaporated, any further increase in heat will cause the temperature of the gas to rise.

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D5W refers to one of the solutions used as an intravenous fluid. It is a 5% by mass solution of dextrose, C6H12O6 in water. The density of D5W is 1.08 g/ml. The molarity of the solution is 0.3 M. Thus, option a is correct.

The formula for molarity is as follows:

Molarity (M) = Moles of Solute ÷ Volume of Solution (in liters).

As a result, let's start by calculating the moles of solute:

Mass (M) = Density (D) x Volume (V)

= 1.08 g/ml x 1000 ml Mass (M) = 1080 g

Since the percentage of dextrose in D5W is 5% by mass, the mass of dextrose in 1000 ml of D5W can be calculated as follows:

Mass of Dextrose = (5/100) x 1080 g Mass of Dextrose = 54 g

Moles of Dextrose = Mass of Dextrose ÷ Molar mass of dextrose

Moles of Dextrose = 54 g ÷ 180 g/mol = 0.3 mol

Molarity (M) = Moles of Solute ÷ Volume of Solution (in liters) = 0.3 mol ÷ 1 L = 0.3 M

Therefore, the molarity of the solution is 0.3 M.  Thus, option a is correct.

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Answer:

As there are many units of mass and volume covering many different magnitudes there are a large number of units for mass density in use. The SI unit of kilogram per cubic metre (kg/m3) and the cgs unit of gram per cubic centimetre (g/cm3) are probably the most commonly used units for density.

Explanation:

Answer: True

Air is a mixture of many things; it's not just Oxygen, but Hydrogen, Carbon, and Nitrogen as well are made up of air. Fun fact: Nitrogen is actually more abundant in air

The major non-covalent interaction that dictates the interaction between chloromethane and water Hydrogen bonding .

The interaction known as hydrogen bonding, which involves a hydrogen atom sandwiched between two other atoms with a high affinity for electrons, is stronger than van der Waals forces but weaker than ionic or covalent bonds. Atoms in separate molecules or distinct regions of the same molecule can form hydrogen bonds with one another. A hydrogen atom (FH, NH, or OH) is covalently bound to one of the pair's (the donor) typically fluorine, nitrogen, or oxygen atoms, with which it shares electrons unevenly. As a result of this high electron affinity, the hydrogen gains a little positive charge.

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(A) 14C undergoes beta decay since it has too many neutrons in its nucleus. In beta decay, a neutron is converted into a proton, and an electron and an antineutrino are emitted from the nucleus. In this case, 14C will decay into 14N with the emission of a beta particle.

(B) 120I undergoes positron emission since it has too many protons in its nucleus. In positron emission, a proton is converted into a neutron, and a positron and a neutrino are emitted from the nucleus. In this case, 120I will decay into 120Te with the emission of a positron.

(C) 102Ag undergoes beta decay since it has too many neutrons in its nucleus. In beta decay, a neutron is converted into a proton, and an electron and an antineutrino are emitted from the nucleus. In this case, 102Ag will decay into 102Cd with the emission of a beta particle.

(D) Sr-89 undergoes beta decay since it has too many neutrons in its nucleus. In beta decay, a neutron is converted into a proton, and an electron and an antineutrino are emitted from the nucleus. In this case, Sr-89 will decay into Y-89 with the emission of a beta particle.

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Helium fusion requires higher temperatures than hydrogen fusion because of the increased electrostatic repulsion between helium nuclei.

Helium has two protons, while hydrogen only has one, the strong nuclear force, which binds the atomic nuclei together, is powerful but short-ranged. To overcome the electrostatic repulsion and allow the strong nuclear force to act, helium nuclei must come very close to each other.  At higher temperatures, the particles have greater kinetic energy, which increases the chances of helium nuclei colliding with enough force to overcome the repulsion.

The temperature required for helium fusion, known as the triple-alpha process, is around 100 million Kelvin, significantly higher than the 15 million Kelvin needed for hydrogen fusion through the proton-proton chain reaction. In summary, the increased electrostatic repulsion between helium nuclei and the need for a closer approach for the strong nuclear force to take effect result in helium fusion requiring higher temperatures than hydrogen fusion.

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