mendeleev is given the most credit for the concept of a periodic table of the elements because:

Answer:

One problem that people may encounter when using a hot and cold compress pillow is that the pillow may not stay hot or cold for a long enough period of time. This can be frustrating for people who are using the pillow to alleviate muscle pain or reduce inflammation, as they may need to continually reheat or refreeze the pillow in order to maintain its therapeutic benefits. To solve this problem, people may need to find a pillow that is better at retaining heat or cold, or they may need to use additional heating or cooling elements (such as hot water bottles or ice packs) in conjunction with the pillow.

Explanation:

16.5 g is the mass of sodium chloride that must be dissolved in the same mass of X to produce the same depression at freezing point.

Avogadro's number (6.022 x 1023) of molecules (or formula units) make up one mole of a substance (ionic compound). The mass of 1 mole of a chemical is indicated by its molar mass. It provides you with the number of grams per mole of a substance, to put it another way.

ΔT = Kc*W*i

Kc = cryoscopy constant of the solute X

W = molality of the solution

i = van't Hoff factor, For organic molecules, such as alanine, i = 1.

n = 45.8/89.09

n = 0.5141 mol

W = 0.5141/1.2 = 0.4284 mol/kg

So, Kc of X is:

4.10 = Kc*0.4284*1

Kc = 9.57 °C.kg/mol

So, if now sodium chloride is added to X, and the temperature change is the same, and i = 1.82:

4.10 = 9.57*W*1.82

W = 0.2354 mol/kg

The number of moles of the solute is then:

W = n/1.2

0.2354 = n/1.2

n = 0.2825 mol

The molar mass of sodium chloride is 58.44 g/mol, thus the mass is the molar mass multiplied by the number of moles:

m = 58.44*0.2825

m = 16.5 g

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Answer:

White color

Explanation:

This compound when heated losses its water of crystallization and become anhydrous copper sulphate

Ribose is an important sugar with a molar mass of 150.15 g/mol and an empirical formula of CH₂O . Its molecular formula is C₅H₁₀O₅

A molecular formula  is defined as the exact number of different atoms present in the molecule of a compound. On the other hand, an empirical formula is defined as the simplest whole number ratio of the different atoms present in a molecule of a compound.

Given here,

molar mass of ribose sugar = 150.15 g/mol

empirical formula = CH₂O

To find: molecular formula

empirical formula mass of ribose sugar

=  (12+ 1×2+ 16) g/mol

= 30 g/mol

molar mass/ empirical formula mass

= 150.15 gmol⁻¹ / 30  gmol⁻¹

=5.005

≈5

we know that

molecular formula

= molar mass/ empirical formula mass  × empirical formula

=5 ×CH₂O

= C₅H₁₀O₅

Thus, the molecular formula is C₅H₁₀O₅

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At 55 °C, the equilibrium constant for this reaction is 6.68. A pharmaceutical chemist prepares 15.0 L of an initial 0.275 M acetic acid and 3.85 M ethanol solution.

Create an equation that can be solved for x by plugging the equilibrium concentrations (expressed in terms of x) into the formula for the equilibrium constant. (d) The equation from subpart (c) is cubic (it bears the formula ax3 + bx2 + cx + d = 0). In general, it is impossible to solve cubic equations in closed form. Indicate the direction (toward product or toward reactants) in which the mixture must change if it is not at equilibrium. The concentrations of SO 2 Cl 2 and SO 2 are 0.108 M and 0.052 M, respectively, in a mixture of the three gases that has reached equilibrium.

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Entropy and the inefficiency of energy transfer are part of the Second Law of Thermodynamics.

The first law of thermodynamics states that neither creation nor destruction of energy is possible. The universe becomes more entropic when a spontaneous process occurs, according to the second law of thermodynamics. Thermodynamics' third law: The entropy of a perfect crystal is 0 at absolute zero Kelvin. The overall entropy of a system may only ever increase or stay constant during spontaneous processes, according to the second law of thermodynamics. If the physical process is irreversible, the overall entropy of the system and its surroundings must increase. For a process to be irreversible, the final entropy needs to be higher than the starting entropy: Sf > Si (irreversible process). The overall entropy of a system and its surroundings can remain constant when a system is in thermodynamic equilibrium or undergoing a reversible process. The second law is sometimes known as the Law of Increased Entropy.

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The number of moles of a monoprotic acid neutralized is equal to 0.025 mol.

A neutralization reaction can be defined as a reaction in which reaction of an acid and base generates salt and water. When a strong acid and a strong base react the salt can be neither acidic nor basic.

When monoprotic acid HA reacts with NaOH (a strong base), the resulting salt is NaA and water.

HA    +    NaOH   →   NaA  +   H₂O

Given, the concentration of NaOH = 0.544 M

The volume of the NaOH = 45.50 ml = 45.50 × 10⁻³

The number of moles of NaOH, n = M × V = 0.544 × 45.50 × 10⁻³ = 0.025 mol

The number of moles of HA monoprotic acid = moles of NaOH = 0.025 mol

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0.0432 moles of CH3CH2OH are contained in 548 mL of a 0.0788 M CH3CH2OH solution.

Molarity is a unit of concentration that expresses the amount of solute in a solution in terms of moles of solute per liter of solvent. It is represented by the symbol M. It is calculated by dividing the number of moles of solute by the number of liters of solvent in the solution. For example, a 0.5 M solution of NaCl would contain 0.5 moles of NaCl dissolved in every liter of water.

To determine the number of moles of a solute in a solution, you can use the formula: moles = (concentration (M) x liters of solution).

In this case, the concentration of the CH3CH2OH solution is given as 0.0788 M and the volume is given as 548 mL. Converting mL to L by multiplying it by 10^-3, we get 0.548 L. By applying the formula, moles = 0.0788 M x 0.548 L = 0.0432 moles of CH3CH2OH.

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The amount of work required to increase the separation of the two ions to an infinite distance is 3.68×10⁻¹⁸joules.

When a push or pull applied to an object causes the object to move, that movement is referred to as work. We refer to energy as the ability to perform the work. The work completed in a given amount of time is referred to as power.

Mg²⁺with a charge is 3.2×10⁻¹⁹C

O²⁻with a charge of −3.2×10⁻¹⁹C

distance = 0.25 = 0.25 ×10⁻⁹m

We know that the constant of proportionality is equal to 8.99×10⁹Jm/C²

Work = -kq₁q₂/d

Substitute given values into the formula,

Work = 8.99×10⁹× 3.2×10⁻¹⁹× -3.2×10⁻¹⁹/ 0.25 ×10⁻⁹

Work =  8.99×10⁹×-1.024×10⁻³⁷/0.25×10⁻⁹

Work = 9.21×10⁻²⁸/ 0.25×10⁻⁹

Work = 3.68×10⁻¹⁸Joules.

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Heterogeneous and homogeneous mixtures are the two types of mixtures.

When compared to homogeneous mixtures, heterogeneous mixtures can be visually divided into individual components. The most prevalent kind of homogeneous mixture is a solution, which can be a solid, liquid, or gas.

Solid, liquid, or gaseous homogeneous mixtures can exist. They are uniform in both appearance and chemical make-up. Water, air, steel, detergent, saltwater mixture, and other substances are examples of homogeneous mixtures. When two or more metals are combined in a specified proportion, an alloy is created.

A combination is said to be heterogeneous if its composition is not constant throughout. Vegetable soup is a complex concoction.

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When a hydrogen atom is part of a molecular structure, it is always a terminal atom.

On the periodic table, hydrogen belongs to the group 1 element. Consequently, a hydrogen molecule contains two valence electrons. There are two identical atoms in the H2 molecule. As a result, any atom can be regarded as a centre atom. An atom attached to a central atom is referred to as a terminal atom if it is not H. Here are two illustrations of this differentiation. Add bonding electrons to the total number of electrons. The end of hydrogen will never come. The centre will often contain the least electronegative element. Since hydrogen can only have two electrons in its valence shell and hence can only make one bond, it can never be the centre atom.

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Phosphorus, which has the atomic number 15 and is located in period 3 and group 15 of the periodic table.

Based on the information, UV light is more likely to damage the material.

Due to the fact that the infrared light bounces off the quartz, which increases its energy, the quartz may become warm.

The colors of paper and fabric can deteriorate due to ultraviolet light from the sun. In the presence of ultraviolet light waves, the chemicals in colored dyes can degrade. Sunburns may also result from ultraviolet radiation.

Paper and other organic materials will deteriorate, bleach, and deteriorate due to ultraviolet radiation. All of these modifications may reduce readability, affect how well artwork is regarded for its aesthetic qualities, and restrict access to the information it contains.

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A quality of matter that is unrelated to a change in its chemical makeup is called a physical property. Density, color, hardness, melting and boiling points, and electrical conductivity.

A quality of matter that is unrelated to a change in its chemical makeup is called a physical property. Density, color, hardness, melting and boiling points and electrical conductivity are a few common examples of physical qualities.

A substance with a given mass and a certain volume in space is referred to as matter. Examples of matters are pens, pencils, toothbrushes, water, and milk, as well as vehicles like cars, buses, and bicycles. Therefore, the matter is divided into two categories: living and non-living.

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Physical properties are characteristics of matter that are independent of changes in its chemical composition. Electrical conductivity, hardness, melt and boiling points, and density.

Physical properties are characteristics of matter that are independent of changes in its chemical composition. Physical characteristics include things like density, color, durability, melting , boiling temperatures, and electrical conductivity, to name a few.

Matter is defined as a material having a certain mass and spatial volume. Pencils, pencils, toothbrushes, water, milk, as well as automobiles, buses, and bicycles, are examples of matters. 

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The force of 9.8 N must be applied to a 1 kg puck to make it accelerate on a friction-free air table of 9.8 m/s²​.

Force is the influence that can change the state of the body of motion or rest. The S.I. unit of measurement of force can be written as Newton and force is a vector.

Force can change the direction as well as the speed. The force can be calculated from the mass (m) & acceleration.

F = ma

Given, the mass of the puck, m = 1 Kg

The acceleration  of the puck, a = 9.8 m/s²​

The force acting on the puck can be calculated as:

F = ma = 1 × 9.8

F = 9.8 N

Therefore, the force needed to apply on a puck is equal to 9.8 N.

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Left C would be neither linear and neither planar since, in accordance with the preceding definition, it has a tetrahedral form.

Since no links cross one another, graph A is planar. Because so many connections overlap, graph B is not plane. Additionally, graph B's linkages cannot be rearranged in a way that makes it planar.

A compound is said to be planar if every atom inside it is located on the same plane. - Take the organic compound, for example. When the carbon atoms of an organic molecule lay within a single plane, the complex is referred to as a planar compound.

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HCl will be the limiting reactant for the above question

When HCl and Ca(OH)2 are mixed, they react to form water and calcium chloride (CaCl2) according to the following equation: HCl(aq) + Ca(OH)2(aq) -> CaCl2(aq) + 2H2O(l). To determine which species is the limiting reactant, we need to compare the amount of HCl and Ca(OH)2 present in the reaction.The number of moles of HCl present in the reaction is given by the equation n=CV, where n is the number of moles, C is the concentration of the solution and V is the volume. Hence  number of HCL moles is:

n = 3.00 M 6.00L = 18.0 moles The number of moles of Ca(OH)2 present in the reaction is given by the equation n=CV, where n is the number of moles, C is the concentration of the solution and V is the volume. So the number of moles of Ca(OH)2 is: n = 2.00 M 5.00L = 10.0 moles. The number of moles of HCl is greater than the number of moles of Ca(OH)2, so HCl will be the limiting reactant.

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The quantity of energy required to convert 0.562 kg ice at -20.0°C to steam at 250°C is equal to 1885.4 KJ.

The specific heat capacity can be described as the amount of energy needed to raise the temperature in one unit of material by one-degree celsius.

The addition or emission of heat from the system will the temperature of the substance will be changed:

Q = mCΔT

Given, the amount of ice, m = 0.562 Kg = 562 g

The change in the temperature = 100 -20 = 80°C

The specific heat capacity of the water, C = 4.18J/g°C

The specific heat capacity of the ice, C = 2.03 J/g°C

The phase transition from ice to steam:

H₁ = 562 × 2.03 × (0-(-20))

H₁ = 22,817 J = 22.8 KJ

The enthalpy of the fusion will be absorbed:

H₂ =  n × H(fus)

The number of moles of water = 562/18 = 31.22 mol

H₂ = 31.22 × 6.02 kJ/mol

H₂ = 187.95 KJ

Phase transition from water at 0°C to water at 100°C:

H₃ = 562 × 4.18 × 100

H₃ = 234 KJ

The phase transition from water at 100°C to steam at 100°C:

H₄ = n × H(vap)

H₄ = 31.22 × 40.7 kJ/mol

H₄  = 1270.65 KJ

The heat to make steam at a temperature of 250°C:

H₅ = m × S×ΔT

H₅ = 562 × 2.02 ×150 = 170 KJ

The total energy needed to convert  0.562 kg ice at -20.0°C to steam at 250.0°C:

H = H₁ + H₂+ H₃+ H₄ +H₅

H = 1885.4 KJ

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In an electrolytic cell, an oxidation-reduction reaction occurs. This type of reaction involves the transfer of electrons from one species to another.

The voltage of an electrolytic cell is typically greater than the voltage of a galvanic cell and is determined by the reactants and the reaction conditions.

In an electrolytic cell, a chemical reaction is driven by an external electrical current. This current causes electrons to flow between two electrodes, typically a cathode and an anode. At the cathode, electrons are gained, leading to a reduction reaction, while at the anode, electrons are lost, leading to an oxidation reaction.

The voltage of an electrolytic cell is typically greater than the voltage of a galvanic cell, and is determined by the reactants and the reaction conditions. The voltage must be high enough to provide the energy needed to drive the reaction, and can be adjusted by changing the current. The reaction rate of an electrolytic cell can also be controlled by varying the current.

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Four water molecules are created for every ten oxygen atoms that are reacting.

A three carbon alkane, propane has the chemical formula C3H8. At room temperature and pressure, it is a gas, but it can be compressed into a liquid for transportation.

Its primary applications include home and water heating, food preparation and storage, clothing drying, and the powering of industrial and farm machinery. The production of plastics and other chemicals in the chemical sector also uses propane as a raw ingredient.

Cons of propane heating

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The periodic chart has many different types of elements. Some elements are metals, some are nonmetals, and yet others are metalloids. Therefore, ductility is the property of metals that explains the given phenomenon.

Metals are hard, conduct electricity, are ductile, lustrous, and malleable materials. Since metals have free electrons that's why they can conduct electricity. Since atoms in metals are very closely packed in a definite crystal solid. It is not brittle that is it can not be broken down easily.

If a strong force acts on the metal towers of the suspension bridge, the towers will not break into pieces, like glass would, but will bend instead. Ductility is the property of metals that explains the given phenomenon.

Therefore, ductility is the property of metals that explains the given phenomenon.

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The volume of methane is 69.15L.

Heat (Q) of methane =Heat(Q) of water

                        Q = mcΔt

water mass = volume(V) × pressure(P)

                    1L×1kg/L=1kg

298 K to 373k = 25°C to 100 °C

c water = 75.2J/mol K =4.2 J/g °C = 4200 J/kg °C

Heat of water (Q) = 1×4200 (100 -25)

Heat of water (Q) = 315000J

∴ Heat of methane = Heat of water = 315000 J

                         = 315 KJ

n (mol) methane = ΔH/Q

                890.4/315 = 2.83

According to the ideal gas law,

PV = nRT

Where;

            P = Pressure

            V = Volume

             n = amount of substance

             R = ideal gas constant

              T = temperature

    Now,  

             V = nRT/P

            V = 2.83 × 0.082 ×298/1

             V = 0.23206 ×298/1

             V = 69.15L

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Option - a is correct answer, H₂SO₄ is a molecular compound that produces H⁺ ions when dissolved in water.

Molecule-shaped inorganic substances are known as molecular compounds. Examples include common compounds like water (H₂O) and carbon dioxide (CO₂). When compared to ionic compounds like sodium chloride, these compounds are very different (NaCl).

Molecules that have a formula that reflects the number of atoms actually bound together in the molecule make up a molecular compound. The bonds between the atoms are joined to form a distinct shape, which is determined by the bond lengths and angles.

Acid produces proton when there is water present.

H₂SO₄ + H₂O → H₃O⁺ + HSO₄⁻

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Ice will not melt as we need 16.72 KJ of heat but we have only 3.76 KJ

In thermodynamics, the enthalpy of fusion can be described as the change in its enthalpy resulting from giving energy, heat, to a specific amount to change its state from a solid to a liquid.

Given the reaction is  2 Na (s) + 2 H₂O(l) → 2 NaOH (aq) + H₂ (g)

Given the mass of sodium = 0.470 g

The moles of sodium = 0.470/23 = 0.020 mol

Given that two moles of sodium (Na) release heat = 368 KJ

Heat released by 0.020 mol of sodium (Na) = (368/2) × 0.020 = 3.76 KJ

Given the mass of ice = 50g

The number of moles = 50/18 = 2.78 mol

For melting, one mole of ice heat is required = 6.02 kJ/mol.

For 2.77 mol of ice = 6.02 × 2.78 = 16.72 KJ

But we have only 3.76 KJ of heat therefore, the ice will not melt.

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The relationship between the enthalpy (ΔH) and entropy (ΔS) of a reaction that is never spontaneous is -ΔH, +ΔS option - B is correct answer.

When a reaction occurs spontaneously, the system doesn't require any additional energy input because the change in free energy is negative.

When the enthalpy change is negative and the entropy change is positive, the reaction is always spontaneous.

The free energy change is always positive and the reaction is never spontaneous if the reaction is endothermic (H positive) and the entropy change S is negative (less disorder).

Although a spontaneous reaction may result in an increase or decrease in entropy or enthalpy, it will always result in a decrease in free energy, which is a negative G.

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Answer:

C- It has been examined, tested and supported over centuries.

Explanation:

The conservation of mass is a scientific law that states that matter cannot be created or destroyed, only transformed from one form to another. This law has been extensively tested and supported over centuries of scientific investigation, and it is considered to be a fundamental principle of chemistry and physics.

Energy transfer from one region of the atmosphere to another is critical in meteorology because it affects the weather.

What is Meteorology?

Meteorology is the science of studying the atmosphere and its phenomena such as weather, climate, and air pollution. It is a branch of the atmospheric sciences and studies the physical processes that make up the atmosphere and how the atmosphere affects the Earth and its inhabitants.

The amount of heat needed to be supplied to the parcel is given by the equation:

Q = nRT∆V

Where n is the number of moles of air, R is the ideal gas constant, T is the temperature in Kelvin and ∆V is the change in volume.

Therefore, the amount of heat needed to be supplied to the parcel is given by:

Q = (1.00 mol)(8.314 J/molK)(300 K)(30.0 dm3 - 22.0 dm3)

Q = 4, 573.2 J.

This is important because it demonstrates the amount of energy that must be supplied in order to keep the parcel of air at a constant temperature as it expands. Without this energy, the temperature of the parcel would decrease as it expands, resulting in a change in its weather patterns.

Hence, the amount of heat needed is: Q = 4, 573.2 J.

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One mole of Helium contains 6.02 × 10²³ atoms. Mass of one mole is 4 g. Then, He containing 5.6 × 10²⁶ atoms weighs 3720.9 g.

Any substance containing 6.02 × 10²³ atoms is called one mole of that substance. This number is called Avogadro number. Thus, one mole of every element contains Avogadro number of atoms.

Helium is second element in periodic table. Atomic mass of helium that is mass of one mole = 4 g

4 g contains 6.02 × 10²³ atoms. Then weight of He containing 5.6 × 10²⁶ atoms is calculated as follows:

no. of moles = 5.6 × 10²⁶/ 6.02 × 10²³ = 930.2

mass of 930.2 moles = 930.2 × 4 =3720.9 g

Therefore, the mass of He containing 5.6 × 10²⁶ atoms is 3720.9 g.

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When two atoms of chlorine and iodine join together to form a covalent bond, their outermost electrons interact to form a chemical bond.

What is a Covalent bond?

A covalent bond is a type of chemical bond that involves the sharing of a pair of electrons between two atoms. Covalent bonds are formed when two atoms come together to share their electrons in order to reach a more stable electron configuration. As a result, the two atoms become bonded together by the attraction of their shared electrons.

The chlorine atom has seven valence electrons, while the iodine atom has seven as well. Both atoms will want to complete their octets, so the two atoms share their outermost electrons with each other. During the formation of the covalent bond, the chlorine atom will donate one of its electrons to the iodine atom, while the iodine atom will donate one of its electrons to the chlorine atom. This sharing of electrons allows the two atoms to form a single bond and fill their octets, forming a covalent bond.

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