how do the methods of scientist lead to knowlodge

Based on the given relative atomic masses of the isotopes, the mass of Na-22 contained in this sample is 0.086 g.

The relative atomic mass of an element is the average mass of one mole of an atom of an element calculated from the atomic masses of the atoms of an element and their relative abundances.

Isotopes of elements are atoms of an element that differ from each other by their masses. The difference in the mass of the isotopes is a result of the difference in the number of neutrons contained within the nucleus of the atoms of the isotopes.

Considering the naturally occurring sodium isotope, Na-23, and the synthetic, radioactive isotope of sodium, Na-22:

the relative atomic mass of Na-23 = 22.9898 u

the relative atomic mass of Na-22 = 21.9944 u.

mass of sample = 2.4698 g

the apparent atomic mass of the isotope = 22.9551 u

Sum of the relative abundances = 1

Let relative abundance of Na-22 = x

relative abundance of Na-22 = 1 - x

22.9898 * (1 - x) + 21.9944 * x = 22.9551

22.9898 - 22.9898x + 21.9944x = 22.9551

0.9954x = 0.0347

x = 0.035

Mass of Na-22 in the sample = 2.4698 * 0.035

Mass of Na-22 in the sample = 0.086 g

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The osmotic pressure of the solution is 25.48atm

Data;

The osmotic pressure of the solution is calculated as

\(\pi = iMRT\)

The Vant hoff factor of the factor = 4

Let's calculate the molarity of the solution;

\(M = \frac{number of moles}{volume}\)

Number of moles = mass / molar mass

\(n = \frac{mass}{molar mass} \\\)

substitute the values into the formula and solve for it

\(n = \frac{69.5}{162.20} \\n = 0.428 moles\)

The molarity of the solution is calculated as

\(M = \frac{number of moles}{volume} \\M = \frac{0.428}{2.35} = 0.182 mol/L\)

The osmotic pressure of the solution is calculated as

\(\pi = iMRT\\\pi = 4 * 0.182 * 35\\\pi = 25.48 atm\)

The osmotic pressure of the solution is 25.48atm

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Answer:  the substance in which another substance

Explanation:

done

Factors that will increase product formation are;

The position of chemical equilibrium is affected by the following factors:

When equilibrium is altered by an external factor, the reaction shifts to annul the effect of that change.

For the reversible exothermic synthesis, low temperature and high pressure will shift the reaction farthest toward the products.

For the reaction of the 2.0g piece of Mg with HNO3. increasing the surface area of magnesium metal as well as increasing the concentration of HNO3 would produce the GREATEST reaction rate.

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Answer:

16.2 g

Explanation:

Step 1: Write the balanced reaction

3 A + 2 B ⇒ 5 C

Step 2: Calculate the moles corresponding to 26.96 g of A

The molar mass of A is 159.7 g/mol.

\(26.96 g \times \frac{1mol}{159.7g} = 0.1688 mol\)

Step 3: Calculate the moles of C produced from 0.1688 moles of A

The molar ratio of A to C is 3:5. The moles of C produced are 5/3 × 0.1688 mol = 0.2813 mol.

Step 4: Calculate the mass corresponding to 0.2813 moles of C

The molar mass of C is 57.6 g/mol.

\(0.2813 mol \times \frac{57.6g}{mol} = 16.2 g\)

18 moles of oxygen can be produced by decomposing 12 moles of KClO₃.

The balanced chemical equation for the decomposition of KClO₃ is:

2KClO₃ → 2KCl + 3O₂

According to the equation, for every 2 moles of KClO₃ decomposed, 3 moles of O₂ are produced. So, to determine how many moles of O₂ are produced by decomposing 12 moles of KClO₃, we can use the following proportion:

2 moles KClO₃ / 3 moles O₂ = 12 moles KClO₃ / x moles O₂

where x is the number of moles of O₂ produced.

Solving for x, we get:

x = (3 moles O₂)(12 moles KClO₃) / (2 moles KClO₃)

x = 18 moles O₂

Therefore, 12 moles of KClO₃ can produce 18 moles of O₂.

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The free energy  of the system is  13.9 kJ/mol. Option D

Gibbs free energy, also known as Gibbs energy or simply free energy, is a thermodynamic property that combines enthalpy (heat content) and entropy (measure of disorder or randomness) to predict the feasibility of a chemical reaction.

It represents the maximum amount of work that can be obtained from a system at constant temperature and pressure. A negative Gibbs free energy value indicates that a reaction is spontaneous and can proceed without input of energy, while a positive value means energy must be added for the reaction to occur.

Now we know that;

ΔG = -RTlnK

R = gas constant

T = temperature

K = equilibrium constant

Then we have;

ΔG = -(8.314 * 298) ln(3.7 * 10^-3)

ΔG = 13.9 kJ/mol

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Answer:evaluations of seismic data

Explanation:

Ortho and para hydrogen are nuclei forms

Taking into account the definition of pH and pOH, the hydroxide ion concentration will be 6.61×10⁻⁵ M.

pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.

The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:

pH= - log [H⁺]= - log [H₃O⁺]

Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:

pOH= - log [OH⁻]

The following relationship can be established between pH and pOH:

pOH + pH= 14

In this case you know that the hydrogen ion concentration is 1.5×10⁻¹⁰ M, this is, [H⁺]= 1.5×10⁻¹⁰ M.

Replacing in the definition of pH:

pH= - log (1.5×10⁻¹⁰ M)

Solving:

pH=  9.82

Replacing in the relationship established between pH and pOH, the pOH can be calculated as:

pOH + 9.82= 14

Solving:

pOH= 14 - 9.82

pOH= 4.18

Replacing in the definition of pOH, the concentration of hydroxide ion is obtained:

- log [OH⁻]= 4.18

Solving:

[OH⁻]= 10⁻⁴ ¹⁸

[OH⁻]= 6.61×10⁻⁵ M

In summary, the hydroxide ion concentration will be 6.61×10⁻⁵ M.

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2.01214904 × 10²² silver atoms are there in 3.74 g of silver

The most common isotope of silver has 60 neutrons, 47 protons, and 47 electrons. Silver is a soft metal with a glossy metallic luster under normal circumstances. It is exceedingly malleable and ductile (can be formed into a wire).

The molar mass of silver is as follows:

Molar mass of Ag = 107.8682 g/mol

The number of atoms in a molar mass is Avogadro’s number:

6.022140857 × 10²³

Therefore 3.8 g of silver contains 3.8 times 6.022140857 × 10²³ divided by 107.8682 that equals 0.03522818 times

6.022140857 × 10²³

= 2.01214904 × 10²² atoms.

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Explanation:

pls the question is not clear to me

The chloride ion (Cl-) has a single negative charge and a full octet of electrons in its outermost shell. It has a tetrahedral shape, with three equatorial lone pairs and one axial bond to a hydrogen or other positively charged ion.

The conjugate acid of chloride ion is HCl (hydrogen chloride), which is formed when the chloride ion accepts a proton (H+) from an acid. The resulting molecule has a positive charge and a linear shape, with a single bond between the hydrogen and chlorine atoms.

The conjugate acid of chloride ion, HCl, is a strong acid that readily donates a proton (H+) to a base to form the chloride ion. In water, HCl dissociates completely to form H+ and Cl- ions. The hydrogen ion (H+) has a positive charge and no electrons, while the chloride ion (Cl-) retains its original tetrahedral shape and three lone pairs of electrons.

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Answer:

So cute and my favorite is Lion and ot is my inner pet with my zodiac sign so cute hehe

The moles of Cl₂(g) will be present at equilibrium is 3.94 × 10⁻⁴ mol

To determine the number of moles of Cl₂(g) at equilibrium, we need to use the given equilibrium constant (Kₑ) and the initial concentrations of CO(g) and COCl₂(g).

Given:

[CO(g)] = 0.3500 mol

[COCl₂(g)] = 0.05500 mol

Kₑ = 1.2 × 10²

The balanced equation for the reaction is:

CO(g) + Cl₂(g) ⇌ COCl₂(g)

Let's denote the number of moles of Cl₂(g) at equilibrium as x. At the start, we have [Cl₂(g)] = 0 mol, but it will change by x at equilibrium.

Using the equilibrium expression, we can write:

Kₑ = [COCl₂(g)] / ([CO(g)] * [Cl₂(g)])

Plugging in the values:

1.2 × 10² = [COCl₂(g)] / (0.3500 * [Cl₂(g)])

To solve for [Cl₂(g)], we need to isolate it on one side of the equation:

[Cl₂(g)] = [COCl₂(g)] / (0.3500 * Kₑ)

Now, let's substitute the given values:

[Cl₂(g)] = 0.05500 / (0.3500 * 1.2 × 10²)

[Cl₂(g)] ≈ 3.94 × 10⁻⁴ mol

Therefore, approximately 3.94 × 10⁻⁴ moles of Cl₂(g) will be present at equilibrium.

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The question was Incomplete, Find the full content below:

Starting with 0.3500 mol CO(g) and 0.05500 mol COCl₂(g) in a 3.050-L flask at 668 K, how many moles of Cl₂(g) will be present at equilibrium

CO(g) + Cl₂(g) ⇄ COCl₂(g)  Ke 1.2 x 10^{2} at 668 K

Answer:

∆Hrxn 1 + ∆Hrxn 3 - ∆Hrxn 2 = ?

-1410.9kJ - 571.6kJ + 3119.4kJ = ?

-2801.1kJ

Answer:

All ionic substances are written as separate ions in solution

All ionic substances are written as separate ions in solution in a complete ionic equation. Therefore, option (C) is correct.

A complete ionic equation can be described as a particular chemical equation where charged atoms such as ions are expressed in a given solution. The complete ionic equations always contain all ions that are formed or act during a particular chemical reaction.

The net ionic equation can be described as an equation that provides information about ions that exists in an aqueous medium. Salts get dissolved in polar solvents such as water which are present as cations and anions in their dissolved state.

The ionic equation shows the chemical species that undergo a chemical change. The ions which are present on both sides of the equation are considered to be spectator ions. Therefore, in order to obtain the net ionic equation we can eliminate them.

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The reaction order and specific reaction rate constant can be determined by performing the kinetics experiment on irreversible polymerization A. Kinetic experiments can be used to investigate the rate and mechanism of chemical reactions. Chemical kinetics is the study of chemical reactions' speed and pathway.

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The average rate of reaction for the time interval from 0 s to 155 s is 0.00444 M/s, the average rate of reaction for the time interval from 155 s to 516 s is 0.00371 M/s, and the average rate of reaction for the time interval from 516 s to 735 s is 0.00412 M/s.

To calculate the average rate of reaction for each successive time interval, we will use the formula:

Average rate of reaction = (change in concentration)/(change in time)

The table is derived as follows:

Time interval (s) [N2O4] (M) Change in [N2O4] (M) Average rate of reaction (M/s)

0-155 2.482 2.482 - 1.794 = 0.688 0.688/155 = 0.00444

155-516 1.794 1.794 - 0.735 = 1.059 1.059/(516-155) = 0.00371

516-735 0.735 0.735 - 0.516 = 0.219 0.219/(735-516) = 0.00412

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Answer:

In an exothermic reaction, the products are at a lower energy than the reactants. The difference between the energy of the reactants and the energy of the products is called the enthalpy change (∆H) of the reaction. For an exothermic reaction, the enthalpy change is always negative.

The amount of matter stays the same between the substances,

Answer: An electron con only exist in a limited number of quantized energy levels.

Explanation:

When cyclohexene is mixed with a sulfonitric mixture (H2SO4/HNO3), it reacts to form nitrocyclohexane and sulfur dioxide.

This reaction proceeds in two steps. Firstly, cyclohexene undergoes electrophilic addition with the nitronium ion (NO2+), which is generated from the reaction between HNO3 and H2SO4. This results in the formation of nitrocyclohexane, giving the initial pale yellow color to the solution.

In the second step, nitrocyclohexane reacts with the excess sulfuric acid present in the mixture. This step is highly exothermic, releasing a significant amount of energy. The sudden release of energy causes an explosion. The exact mechanism of the explosive reaction is complex, involving the generation of reactive intermediates. It is believed that the reaction proceeds via a radical mechanism, where nitrocyclohexane decomposes into highly reactive nitrogen and carbon-centered radicals. These radicals further react with sulfur dioxide, which is produced in the reaction, to form stable compounds. As a result, the solution turns dark brown after the explosion.

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Answer:

No. it,s not possible.

Explanation:

Because you know that ionic compound is having large inter-molecular forces. -77C* is for a compound having v.very small inter-molecular forces.you must know that M.B is directly varing with inter-molecular forces.

Answer:

The answer is "Option b".

Explanation:

Given equation and value:

\(\Rightarrow C_2H_2 \ (g)+ \frac{5}{2}O_2 \ (g) \longrightarrow 2CO_2\ (g)+H_2O\ (g)\)

\(\left\begin{array}{ccc}C \equiv C&839\\C-H &413\\O=O &495\\ C=O &799\\ O-H &467 \end{array}\right \\\\\)

calculating equation value:

\(\Rightarrow 839 + 2(413) +\frac{5}{2} (495) \longrightarrow 2(2)799+2 \times 467 +E\)

\(\Rightarrow 839 + 826 +1237.5 = 3196+934 +E\\\\\Rightarrow 2902.5 =4130 +E\\\\\Rightarrow 2902 = 4130 +E\\\\\Rightarrow 2902 - 4130 +E\\\\\Rightarrow E = -1228 \ KJ \\\\\)

The heat(enthalpy) of combustion of acetylene = -1228 kJ

The heat of combustion refers to the amount of heat released when 1 mole of a substance is burned.

The chemical reaction is given in the equation;

The bond energy of the reactant is:

Following the bond energies given in the question, we have:

= ( 1 × 839) +(5/2 × 495) +(2 × 413)

= 2902.5 kJ

The bond energy of the product is:

= (4× 799) +(2 × 467)

= (3196 + 934) kJ

= 4130 kJ

The heat(enthalpy) of combustion of acetylene = bond energy of reactant - bond energy of the product.

The heat(enthalpy) of combustion of acetylene = 2902.5 kJ - 4130 kJ

The heat(enthalpy) of combustion of acetylene = -1227.5 kJ

≅  -1228 kJ

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Answer:

a. The Zn and HCl both retained their identity.

Answer:

The answer is "The First choice".

Explanation:

The whole question can be found in the file attached.

The water vapor inside the air freezes thru the entrance of its nitrogen. This is because liquid nitrogen has a very low temperature and seems to be sufficiently cold to condensed and freeze the steam of water. At air pressure, it has a boiling temperature of -196°C. Freezing the skin producing freeze or cold burns can be associated with direct contact.