Helium is a gas used to fill balloons.it is present in the air in very small quantitie.diffusion can be used to separate it from the air. air at 1000 degrees Celsius is on one side of a porous barrier.the air which passes through the barrier has a large amount of helium in it. why does the air on the other side of the barrier contain more helium?​

The symbol [o] written above a reaction arrow means that oxygen is present in the reaction. The symbol [o] indicates that oxygen is a reactant or a product in the reaction equation. An arrow usually represents a chemical reaction in chemical equations.

In chemical equations, the [o] symbol is used to indicate oxygen as a reactant or product. Here, we must understand that Oxygen is one of the essential elements of the periodic table. It is colorless, odorless, and tasteless gas. Its atomic number is 8, and it is a member of the chalcogen group in the periodic table. The element oxygen is essential for most organisms to perform cellular respiration. It is also used extensively in the chemical industry, as well as in various other industrial processes.

Therefore, the symbol [o] is used to show the presence of oxygen in the reaction and to indicate the role of oxygen in the reaction. It is used in reaction equations to differentiate between reactants and products and to provide a clear picture of the reaction taking place.

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a. UV radiation is higher energy, causing DNA damage and increased skin cancer risk.

b. Lead shields X-rays due to density, but gamma radiation requires thicker, denser materials for effective blocking.

a. Ultraviolet (UV) radiation has shorter wavelengths and higher energy compared to visible light. This higher energy allows UV radiation to penetrate the skin and interact with cellular components, including DNA. UV radiation can cause damage to the DNA in skin cells, leading to mutations and an increased risk of skin cancer. Tanning is considered dangerous because it indicates exposure to UV radiation, which can have harmful effects on the skin.

b. X-rays and gamma radiation are both forms of high-energy electromagnetic radiation. However, they differ in their ability to penetrate materials. X-rays have lower energy and can be blocked by materials with high density and atomic number, such as lead. Lead effectively shields X-rays by absorbing and scattering the radiation, preventing it from reaching sensitive tissues. On the other hand, gamma radiation has higher energy and requires thicker and denser materials, such as concrete or lead combined with other shielding materials, for effective attenuation.

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The enthalpy of the given reaction is -1416 kJ.

1. 2M(s) + 6HCl(aq) → 2MCl₃(aq) + 3H₂(g); ΔH₁ = -609 kJ

2. HCl(g) → HCl(aq); ΔH₂ = -74.8 kJ

3. H₂(g) + Cl₂(g) → 2HCl(g); ΔH₃ = -1845.0 kJ

4. MCl₃(s) → MCl₃(aq); ΔH₄ = -481.0 kJ

We have to calculate the enthalpy of the following reaction:

2M(s) + 3Cl₂(g) → 2MCl₃(s)

Enthalpy change for the given reaction will be equal to the sum of enthalpies of the first and third reactions and the negative of enthalpy of the fourth reaction. ΔH2 will be ignored since it is not included in the reaction equation.

ΔHrxn = [ΔH₁ + ΔH₃] + [-ΔH₄]

ΔHrxn = [(-609 kJ) + (-1845.0 kJ)] + [481.0 kJ]

ΔHrxn = -1416 kJ

Therefore, the enthalpy of the given reaction is -1416 kJ.

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Complete question is:

Consider these reactions, where M represents a generic metal.

1. 2M(s) + 6HCl(aq) → 2MCl₃(aq) + 3H₂(g); ΔH₁ = -609 kJ

2. HCl(g) → HCl(aq); ΔH₂ = -74.8 kJ

3. H₂(g) + Cl₂(g) → 2HCl(g); ΔH₃ = -1845.0 kJ

4. MCl₃(s) → MCl₃(aq); ΔH₄ = -481.0 kJ

Use the information above to determine the enthalpy of the following reaction:

2M(s) + 3Cl₂(g) → 2MCl₃(s)

Answer: B) the ideal gas constant

Explanation:

All gases obey an equation of state known as the Ideal gas law: PV = nRT,

Where Pressure = P, volume = V, and temperature = T, n is the number of moles of the gas and R is the Ideal Gas Constant = 8.314 joules per kelvin per mole.

Therefore the Correct Option is B.

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The bioavailability of calcium depends in part on vitamin D intake, amount of calcium consumed, and the presence of other substances that affect absorption.

The bioavailability of calcium is determined by a variety of factors. The bioavailability of calcium is the proportion of calcium ingested that is actually absorbed and used by the body. Calcium bioavailability is influenced by a variety of factors, including the amount of calcium consumed, vitamin D intake, and the presence of other substances that affect absorption.

Calcium is best absorbed in doses of no more than 500 mg at a time. Calcium is absorbed most effectively when consumed with meals. Calcium bioavailability is decreased by high levels of sodium, caffeine, and alcohol. Calcium is absorbed more effectively when it is consumed with other minerals and nutrients such as vitamin D, magnesium, and phosphorus.

Vitamin D is necessary for calcium absorption, and calcium cannot be utilized without it. Vitamin D deficiency is a major cause of calcium deficiency. Vitamin D is produced in the skin when it is exposed to sunlight. Vitamin D supplements or fortified foods are also available.

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The nuclear model of the atom was proposed by Rutherford and his co-workers in 1911.

The model was a result of their famous alpha-particle scattering experiment. The experimental evidence for the development of the nuclear model of the atom was given by the alpha-particle scattering experiment.In this experiment, a thin gold foil was bombarded with alpha particles.

It was observed that most of the alpha particles passed straight through the foil, but a few of them were deflected by large angles. Some of the alpha particles even returned back to the source.This observation was contrary to the plum pudding model of the atom proposed by Thomson.

According to this model, the positive charge of the atom was concentrated in a very small volume called the nucleus. The electrons revolved around the nucleus in circular orbits. The nuclear model of the atom explained the experimental results of the alpha-particle scattering experiment and became the basis for our current understanding of the atomic structure.

In conclusion, the experimental evidence for the development of the nuclear model of the atom was given by the alpha-particle scattering experiment which was a result of Rutherford and his co-workers in 1911.

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The modified formula for the multiplicity of the two-dimensional ideal gas is Ω = (1/N!) * (Aⁿ / hⁿ) * (2πm/ħ²)ⁿ/²

(a) In a similar manner to the three-dimensional ideal gas, we can use the formula for the multiplicity (Ω) of a two-dimensional ideal gas given by the equation:

Ω = (1/N!) * (Vⁿ / h²ⁿ)) * (4πm/2πħ²)ⁿ/²

However, since the gas is now in a two-dimensional universe, we need to modify this equation to account for the area (A) instead of volume (V). The modified formula for the multiplicity of the two-dimensional ideal gas is:

Ω = (1/N!) * (Aⁿ / hⁿ) * (2πm/ħ²)ⁿ/²

(b) The expression for the entropy (S) of the two-dimensional ideal gas can be obtained by using the relationship between entropy and multiplicity:

S = k * ln(Ω)

Substituting the modified formula for Ω derived in part (a), we get:

S = k * ln[(1/N!) * (Aⁿ / hⁿ)) * (2πm/ħ²)ⁿ/²]

S = k * [ln(Aⁿ) - N * ln(h) + (N/2) * ln(2πm/ħ²) - ln(N!)]

(c) To determine the temperature (T), pressure (P), and chemical potential (μ), we need to take partial derivatives of entropy (S) with respect to energy (U), area (A), and number of particles (N).

Temperature (T):

(∂S/∂U) = 1/T

Pressure (P):

(∂S/∂A) = P/T

Chemical potential (μ):

(∂S/∂N) = -μ/T

To simplify the expressions further, it is necessary to evaluate the logarithmic term and apply Stirling's approximation for the factorial term (N!). The resulting expressions may be complex and involve various constants and logarithms.

It is important to note that since we are in a two-dimensional universe, the concept of pressure is defined as force per unit length instead of force per unit area as in three dimensions. Additionally, the chemical potential reflects the behavior of the gas in two dimensions.

The specific simplification and interpretation of the results would require further mathematical calculations and analysis based on the given expressions and the specific values of U, A, and N.

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Answer:

Answer and Explanation: To determine the number of moles of silver (Ag), we simply need to divide the number of atoms of Ag by the Avogadro's number, N , which is equal to 6.02 10 atoms of Ag per mole of Ag. Therefore, c) 6.3 moles of Ag are present in a sample of 3.8 10 atoms Ag.

When an electrical current is applied to an aqueous solution of lithium sulfide, hydrogen gas will be produced at the cathode and sulfur will be produced at the anode.

At the cathode, positively charged hydrogen ions (H+) gain electrons and are reduced to hydrogen gas (H2).2H+ + 2e- → H2

At the anode, negatively charged sulfide ions (S2-) lose electrons and are oxidized to form elemental sulfur (S).

S2- → S + 2e-

It's worth noting that lithium ions (Li+) will also be present in the solution but they will not be produced at either the anode or cathode.

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The factors that determine how much chemical energy an object has include the object's mass, chemical composition, and the types of bonds that are present.

Chemical energy is one of the many different types of energy that exist, and it is the energy that is stored within an object's chemical bonds. Chemical energy has the potential to be released through a chemical reaction.

The factors that determine how much chemical energy an object has include the object's mass, chemical composition, and the types of bonds that are present.

The more mass an object has, the more chemical energy it will contain because there will be more bonds between the particles in the object's molecules.

The chemical composition of an object also plays a role in determining its chemical energy. For example, molecules that contain more carbon and hydrogen atoms will typically have more chemical energy than molecules that contain fewer carbon and hydrogen atoms.

Finally, the types of bonds that are present in an object also play a role in determining its chemical energy. Bonds that are stronger and more stable will contain more chemical energy than bonds that are weaker and less stable.

In conclusion, the amount of chemical energy an object contains depends on its mass, chemical composition, and the types of bonds that are present in it. The chemical energy is the potential energy that can be released through a chemical reaction.

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The pH of the base solution after adding the [tex]HNO_3[/tex] solution is approximately 2.14.

To calculate the pH of the base solution after adding the [tex]HNO_3[/tex] solution, we need to consider the acid-base reaction between methylamine ([tex]CH_3NH_2[/tex]) and nitric acid ([tex]HNO_3[/tex]). Methylamine acts as a base, while nitric acid is an acid. The reaction can be represented as follows:

[tex]CH_3NH_2 + HNO_3 \rightarrow CH_3NH_3^+ + NO_3^-[/tex]

Since methylamine is a weak base, we need to consider its reaction with water as well:

[tex]CH_3NH_2 + HNO_3 \rightarrow CH_3NH_3^+ + NO_3^-[/tex]

To solve this problem, we'll use the Henderson-Hasselbalch equation, which relates the pH of a solution to the pKa and the ratio of the conjugate acid and base forms. The pKa of methylamine is given as 3.36.

1. Calculate the initial moles of methylamine in the base solution:

Initial moles of methylamine = volume of solution (L) * molarity of methylamine (mol/L)

Initial moles of methylamine = 0.1323 L * 0.7100 mol/L

Initial moles of methylamine = 0.093963 mol

2. Calculate the moles of nitric acid added to the solution:

Moles of nitric acid = volume of solution (L) * molarity of nitric acid (mol/L)

Moles of nitric acid = 0.1114 L * 0.7500 mol/L

Moles of nitric acid = 0.08355 mol

3. Calculate the moles of methylamine remaining after the reaction:

Moles of methylamine remaining = Initial moles of methylamine - Moles of nitric acid added

Moles of methylamine remaining = 0.093963 mol - 0.08355 mol

Moles of methylamine remaining = 0.010413 mol

4. Calculate the concentration of the conjugate acid ([tex]CH_3NH_3^+[/tex]) formed:

The concentration of [tex]CH_3NH_3^+[/tex] = moles of methylamine remaining / volume of solution (L)

Concentration of [tex]CH_3NH_3^+[/tex] = 0.010413 mol / (0.1323 L + 0.1114 L)

The concentration of [tex]CH_3NH_3^+[/tex] = 0.010413 mol / 0.2437 L

Concentration of [tex]CH_3NH_3^+[/tex] = 0.0427 M

5. Use the Henderson-Hasselbalch equation to calculate the pH of the base solution:

pH = pKa + log10 ([concentration of [tex]CH_3NH_3^+[/tex]] / [concentration of [tex]CH_3NH_2[/tex]])

Since the pKa of methylamine is given as 3.36:

pH = 3.36 + log10 (0.0427 M / 0.7100 M)

pH = 3.36 + log10 (0.0601)

pH = 3.36 + (-1.22)

pH = 2.14

Therefore, the pH of the base solution after adding the [tex]HNO_3[/tex] solution is approximately 2.14.

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Water vapor is the gas that has a variable concentration in the atmosphere. Its concentration can vary greatly depending on factors such as temperature, humidity, and weather patterns.

Water vapor is constantly being added to the atmosphere through evaporation from bodies of water and transpiration from plants. It can also condense into clouds and precipitation, leading to fluctuations in its concentration in different regions and over time. On the other hand, carbon dioxide, methane, and ozone are considered trace gases and their concentrations in the atmosphere are relatively stable, with variations mainly due to human activities and natural processes.

The gases that have variable concentrations in the atmosphere are:

- Carbon Dioxide (CO2): The concentration of carbon dioxide in the atmosphere can vary due to natural processes such as photosynthesis and respiration, as well as human activities like the burning of fossil fuels. Changes in land use, deforestation, and industrial processes can contribute to fluctuations in carbon dioxide levels.

- Methane (CH4): Methane concentrations in the atmosphere can vary as a result of both natural and anthropogenic sources. Natural sources include wetlands, termites, and natural gas seepage, while human activities such as livestock farming, rice cultivation, and fossil fuel extraction contribute to increased methane emissions.

- Ozone (O3): Ozone concentrations in the atmosphere can vary regionally and temporally. While ozone is naturally present in the stratosphere, where it plays a crucial role in protecting the Earth from harmful UV radiation, ground-level ozone is formed through chemical reactions involving pollutants emitted by human activities, including vehicle emissions and industrial processes.

- Water Vapor (H2O): Water vapor is highly variable in the atmosphere and its concentration can vary significantly depending on the location, temperature, and weather conditions. It is influenced by factors such as evaporation from bodies of water, transpiration from plants, and atmospheric dynamics. Water vapor is a key component of the Earth's climate system and plays a crucial role in weather patterns.

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The symbol for carbon is C.

The symbol for hydrogen is H.

The symbol for nitrogen is N.

The symbol for iron is Fe.

The symbol for copper is Cu.

These symbols are derived from the names of the elements in English and Latin. The choice of symbols for elements is based on several factors, including the element's name, its Latin translation, and historical reasons.

Carbon, with an atomic number of 6, is represented by the symbol C. This symbol comes from the Latin word "carbo," meaning charcoal or coal, which reflects carbon's association with carbon-based materials.

Hydrogen, with an atomic number of 1, is represented by the symbol H. The symbol H is derived from the first letter of its name, hydrogen.

Nitrogen, with an atomic number of 7, is represented by the symbol N. The symbol N is derived from the Latin word "nitrogenium," which comes from "nitrum" (saltpeter) and "gen" (to produce), reflecting nitrogen's role in the formation of nitrates.

Iron, with an atomic number of 26, is represented by the symbol Fe. The symbol Fe comes from the Latin word "ferrum," which means iron. This symbol is derived from the ancient name for iron and has been used for centuries.

Copper, with an atomic number of 29, is represented by the symbol Cu. The symbol Cu comes from the Latin word "cuprum," which means copper. The symbol Cu is derived from the ancient name for copper and has been used since ancient times.

In summary, the symbols for carbon, hydrogen, nitrogen, iron, and copper are C, H, N, Fe, and Cu, respectively. These symbols are based on the element names, Latin translations, and historical conventions.

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Neon (Ne) has 8 electrons in its outer shell. Neon belongs to the noble gases group on the periodic table, specifically Group 18 or Group 8A.

The chemical elements are arranged in rows and columns on the periodic table, also known as the periodic table of the elements. It is frequently used in physics and other sciences as a chemistry organizing symbol.

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The enolase reaction is inhibited by sodium fluoride (NaF).

Enolase is an enzyme that catalyzes the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP) in the glycolysis pathway. The reaction involves the removal of a water molecule from 2-PG to form a double bond in the enol form, which is then converted to the keto form to produce PEP.

The reaction can be represented as follows:

2-Phosphoglycerate (2-PG) ⇌ Phosphoenolpyruvate (PEP)

The presence of sodium fluoride (NaF) inhibits this reaction. NaF is known to interact with metal ions, particularly magnesium ions (Mg2+), which are essential cofactors for enolase activity. NaF forms a complex with Mg2+ ions, reducing their availability for enolase, thus inhibiting its catalytic function.

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Proper storage and handling of decontaminated PPE help ensure its integrity and effectiveness when needed for future use. D) None of these is correct.

After undergoing decontamination, personal protective equipment (PPE) should not be placed in areas such as the vehicle cab, living area, or sleeping area. These locations can potentially contaminate the previously decontaminated PPE and compromise its effectiveness. It is important to maintain a clear distinction between clean and contaminated areas to prevent cross-contamination.

Ideally, decontaminated PPE should be stored in designated areas or containers specifically designed for clean items. These areas should be separate from areas where contamination may occur.

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The concentration of the species in a 0.140 M solution of H₂CO₃ is given by:

[H₂CO₃] = 0.140 M, [HCO₃⁻] = 1.45×10^−7 M, [CO₃²⁻] = 1.45×10^−10 M, [H₃O⁺] = 4.5×10^−4 M, [OH⁻] = 2.2×10^−11 M.

Carbonic acid is a diprotic acid, which means that it has two acid dissociation constants. The first step is for the acid to donate a proton to form bicarbonate, and the second step is for the acid to donate another proton to form carbonate. H₂CO₃(aq) + H₂O(l) ⇌ H₃O⁺(aq) + HCO₃⁻(aq) Ka₁ = 4.3×10−7

HCO₃⁻(aq) + H₂O(l) ⇌ H₃O⁺(aq) + CO₃²⁻(aq) Ka₂ = 4.7×10−11

The formula for the concentrations of the species present in the solution is as follows:

[H₂CO₃] = 0.140 M

[HCO₃⁻] = Ka₁

[H₂CO₃]/[H₃O⁺] = 1.45×10^−7 M

[CO₃²⁻] = Ka₂[HCO₃⁻]/[H₃O⁺]

= 1.45×10^−10 M

[H₃O⁺] = Ka₁[H₂CO₃]/[HCO₃⁻]

= 4.5×10^−4 M

[OH⁻] = Kw/[H₃O⁺] = 2.2×10^−11 M, where Kw is the ion product constant for water.

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Spiral galaxies have spiral arms that emanate from a central disk. Elliptical galaxies are shaped like a rugby ball and lack spiral arms. Irregular galaxies have a chaotic, asymmetric shape.

Galaxies are the building blocks of the Universe. They are the massive assemblages of stars, gas, and dust that make up the visible Universe. Galaxies are categorized into three major groups based on their shapes: spiral, elliptical, and irregular. Spiral galaxies have spiral arms that emanate from a central disk. They have a central bulge with a bar or without a bar. Spiral galaxies are usually rich in gas and dust, which form stars. They are considered to be sites of star formation, and they typically have a blue color. Examples include the Milky Way and Andromeda.

Elliptical galaxies are shaped like a rugby ball and lack spiral arms. They range in size from dwarf galaxies to giants. They are generally spherical, with a central bulge, and lack spiral arms. They are reddish or yellow in color and are considered to be old and no longer forming stars. Irregular galaxies have a chaotic, asymmetric shape. They do not have any well-defined shape or structure. They are often distorted by interactions with other galaxies or as a result of being a remnant of a galaxy collision. Irregular galaxies are blue or red and contain both young and old stars. Examples include the Magellanic Clouds.

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The chemical formula for cobalt(III) hydroxide is Co(OH)₃. In the chemical formula, Co represents the element cobalt, and OH represents the hydroxide ion.

The Co represents the element cobalt, and OH represents the hydroxide ion. The hydroxide ion (OH⁻) consists of one oxygen atom (O) bonded to one hydrogen atom (H), and it carries a negative charge.

In cobalt(III) hydroxide, the cobalt ion has a +3 charge (Co³⁺). Since the hydroxide ion carries a -1 charge, it takes three hydroxide ions to balance the charge of one cobalt(III) ion.

By combining the cobalt ion and the hydroxide ions in the appropriate ratio, we get Co(OH)₃ as the chemical formula for cobalt(III) hydroxide.

Roman numeral (III) in the name "cobalt(III) hydroxide" indicates the oxidation state of the cobalt ion, which is +3. Cobalt can form different ions with varying charges, and the oxidation state affects the chemical behavior of the element in compounds.

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Mercury is a dense and small planet. It orbits closer to the sun than any other planet in the solar system, with an orbital distance of 36 million miles.

As a result of its proximity to the sun, mercury has a surface temperature range of -280 degrees Fahrenheit to 800 degrees Fahrenheit, making it the planet with the greatest temperature extremes. These two properties, size, and density, indicate that Mercury is differentiated.

Mercury's small size implies that it has a relatively small volume. However, the planet's high density implies that the materials that make up the planet are compressed. The compression caused the materials to rearrange according to density, with the most dense materials at the center.

As a result, Mercury has a core made up of iron and nickel, as well as a mantle composed of silicates that surround the core.In conclusion, the properties of density and small size imply that Mercury is differentiated.

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Bromothymol blue is a pH-indicator that changes color depending on the acidity or alkalinity of a solution, At pH 9, the bromothymol blue solution would appear blue-green in color.

Bromothymol blue is typically yellow in acidic solutions with a pH below 6. At neutral pH (around 7), it transitions to a green color. As the pH increases, bromothymol blue turns blue and then blue-green as it reaches alkaline conditions.

At pH 9, which is slightly alkaline, the bromothymol blue solution would exhibit a blue-green color. This color transition occurs due to the change in the ionization state of the indicator molecule as the pH changes.

The blue-green color indicates that the solution is more alkaline than neutral but not strongly basic.

It's important to note that the color change of bromothymol blue can vary slightly depending on factors such as concentration, temperature, and specific experimental conditions.

Additionally, precise color interpretation is best done by comparing the observed color with a standard color chart or known pH values.

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The pair of isotopes is O 16 and O 18.

An isotope is a chemical element that has the same number of protons in the nucleus but a different number of neutrons. This gives them a different atomic weight. For example, carbon-12, carbon-13, and carbon-14 are isotopes of carbon.

The given options, OHH 32, s. 32 5-2 16 16 O02, 03 O14 C, LAN N, do not match the criteria to be isotopes of each other. OHH32 is not an element, while s. 325-2 is an ion. O02 and O03 are isotopes of oxygen but have different atomic numbers. Lastly, 14C and LAN N are not the isotopes of each other because they are from different elements.

Thus, the correct pair of isotopes is O16 and O18.

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The element that has two electrons in its 4d sublevel is Ruthenium (Ru) with the atomic number of 44.

Ruthenium (Ru) is a rare transition metal from the platinum group of the periodic table. It is a hard, brittle, silvery-white metal with a slight bluish tint and an atomic number of 44. Ruthenium is one of the densest materials, and it has four stable isotopes. It is commonly found in ores containing other platinum metals.

Ruthenium is frequently used in electrical contacts due to its hardness, wear resistance, and low contact resistance. It is also utilized in some alloys with platinum and other platinum-group metals to make wear-resistant electrical contacts. Ruthenium can also be used as a catalyst in some chemical reactions. It can oxidize and reduce many molecules, making it useful in various oxidation-reduction reactions.

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The reducing agent in the following reaction 2Na + 2H₂O → 2NaOH + H₂ is Na. The correct answer is option A.

Oxidation-reduction reactions or redox reactions are chemical reactions that involve the transfer of electrons between two species. In such reactions, the reducing agent is the one that is oxidized, i.e., it loses electrons. On the other hand, the oxidizing agent is the one that is reduced, i.e., it gains electrons. The reducing agent reduces the oxidizing agent by donating electrons to it.

In this reaction, sodium (Na) is oxidized, and hence acts as the reducing agent. Na loses an electron and becomes positively charged Na+ ion, which then combines with hydroxide (OH-) ion to form sodium hydroxide (NaOH). The hydrogen ion (H+) produced by the dissociation of water is reduced to hydrogen gas (H₂) by accepting the electron donated by sodium.

Thus, the reducing agent in the reaction 2Na + 2H₂O → 2NaOH + H₂ is Na. The correct answer is option A.

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The factors that cause changes between the solid and liquid state are temperature and pressure.

The physical state of matter can be altered by changing the temperature and pressure. A solid is a state of matter in which molecules are tightly packed and cannot move freely. When heat energy is added to a solid, the molecules gain kinetic energy and begin to vibrate more vigorously, eventually causing them to break free from their rigid structure. This process is called melting, and it results in a change from a solid to a liquid state. The reverse process, from a liquid to a solid state, occurs when heat energy is removed from a liquid, causing the molecules to lose kinetic energy and become more organized.

In addition to temperature, pressure can also cause changes between solid and liquid states. As pressure increases, molecules become more tightly packed and move more slowly. This can cause a substance to change from a liquid to a solid state. The reverse process, from a solid to a liquid state, can occur when pressure is reduced.  

Overall, temperature and pressure are the two primary factors that cause changes between the solid and liquid state of matter.

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Answer:

The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.

Explanation:

Answer:

Atomic nuclei consist of electrically positive protons and electrically neutral neutrons.

Explanation: Hope it helps :)

Answer:

mass=8,640g

Explanation:

[tex]n = \frac{mass}{molar \: mass} [/tex]

where

mole(n)= 120mol

Molar mass = Ar2

= 36×2

= 72g/mol.

Mass = ?

Therefore mass =

[tex]120 = \frac{m}{72} . \\ 120 \times 72 = m \\ 8640g = m[/tex]

Mendeleev constructed his periodic table based on the similarities in the properties of elements and the periodic repetition of their physical and chemical properties.

Mendeleev constructed his periodic table based on certain observations. He observed that the elements have similar chemical properties, and he arranged them in the same vertical column. The properties of elements show periodic repetition. He took the atomic weights of the elements and arranged them in a periodic manner. He also kept some gaps in the table for the yet-to-be-discovered elements and predicted their properties. This led to the development of the concept of periodicity.

In his table, Mendeleev also recognized the existence of certain trends among the properties of elements. For instance, the first element in each group has the smallest atomic weight. The atomic weights of elements increase from left to right across each row. The most reactive metallic elements are at the bottom left-hand corner of the table, while the non-metallic elements are at the top right-hand corner of the table.

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The term used for the geometrical isomer shown below is the term "cis-isomer."

Cis-trans isomerism, also known as geometric isomerism or configurational isomerism, is a type of stereoisomerism that occurs in alkenes and cyclic compounds.

Cis-isomer and trans-isomer are two types of stereoisomers.

Cis-isomer refers to a molecule in which two functional groups or substituents are on the same side of the double bond or ring.

Cis-isomerism occurs when substituents on a double bond or ring have the same spatial orientation.

The molecule shown below is an example of a cis-isomer.

Cis-isomers and trans-isomers have the same molecular formula and sequence of bonded atoms but differ in their spatial arrangement.

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