Witch hazel solution, an astringent for skin,
contains 14% ethyl alcohol, C₂H5OH, by volume.
How many mL of ethyl alcohol are contained in a
16 fluid ounce bottle of witch hazel?

Answer:

True (the statement is correct)

Explanation:

Yeah, resilience describes an ecosystem's ability to maintain dynamic equilibrium.

Resilience is the capacity to cure from difficulties. Hence, the statement is true.

The pH of the ethanoic acid can be obtained as 3.39.

We know that the pH has to do with the negative logarithm of the hydrogen ion concentration of a solution. We know that we have to apply the formula for the pH so as to obtain the pH of the solutions.

pH of hydrochloric acid = - log( 0.100) = 1

pH of sulphuric acid = - log( 0.025 ) =1.6

pH of nitric acid = - log (0.005) = 2.3

pH of phosphoric acid = - log ( 0.200) = 0.69

We say that HCl is a strong acid because it s able to dissociate completely in solution while the ethanoic acid does not dissociate completely in solution.

For the dissociation of ethanoic acid we have;

Ka = [[tex]H_{3} O^+[/tex]] [[tex]CH_{3} COO^-[/tex]]/[[tex]CH_{3} COOH[/tex]]

1.7 x10^-5 = x^2/0.01 - x

1.7 x10^-5(0.01 - x) =x^2

1.7 * 10^-7 - 1.7 x10^-5x - x^2 = 0

x^2 + 1.7 * 10^-5x - 1.7 * 10^-7 = 0

x=0.0004 M

pH = - log(0.0004 )

pH = 3.39

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The percent yield of KCl is 82.2 %. The percent yield of sodium hydroxide is 36.99 %. The reaction produces about 1.35 L of water.

1)

Number of moles of potassium chlorate = 1200.0 grams/122.55 g/mol

= 9.79 moles

If 2 moles of potassium chlorate produces 2 moles of potassium chloride then 9.79 moles of potassium chloride is produced.

Theoretical yield =  9.79 moles * 74.55 g/mol

= 729.8 g

Percent yield = actual/theoretical * 100/1

=  600.0 grams / 729.8 grams * 100/1

= 82.2 %

2)

Number of moles of water = 705 grams/18 g/mol = 39.2 moles

Number of moles of sodium oxide = 302 grams/62 g/mol

= 4.9 moles

If the reaction is 1:1 the sodium oxide is the limiting reactant

1 mole of sodium oxide produces 2 moles of sodium hydroxide

4.9 moles of sodium oxide produces 4.9 moles  * 2 moles/ 1 mole

= 9.8 moles

Theoretical yield of the sodium hydroxide = 9.8 moles * 40 g/mol

= 392 g

Percent yield = 145 g/392 g * 100/1

= 36.99 %

3)

Mass of the pentane = density * volume

= 0.6262 g/mL * 3000 mL

= 1878.6 g

Number of moles of the pentane = 1878.6 g/72 g/mol

= 26.1 moles

Number of moles of oxygen = 3200.0 g/32 g/mol

= 100 moles

If 1 mole of pentane reacts with 8 moles of oxygen

26.1 moles of pentane reacts with 26.1 moles * 8 moles/1 mole

= 208.8 moles

Hence oxygen is the limiting reactant

If 8 moles of oxygen produces 6 moles of water

100 moles of oxygen would produce 100 moles * 6 moles/8 moles

= 75 moles

Mass of water produced = 75 moles * 18 g/mol = 1350 g

Since volume = mass/density

Volume of water = 1350 g/1.00 g/mL

= 1350 mL or 1.35 L

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Calcium chloride, CaCl2, is a white, crystalline salt that is very soluble in water.

Calcium chloride is an inorganic compound, a salt with the chemical method CaCl 2. it is a white crystalline strong at room temperature, and it's miles exceptionally soluble in water.

Solubility is defined as the maximum amount of a substance in an effort to dissolve in a given quantity of solvent at a special temperature. Solubility is a characteristic asset of a particular solute-solvent combination, and special substances have significantly differing solubilities.

Solubility refers to the finest quantity of solute that may dissolve in a recognized quantity of solvent at a given temperature. In a solvent, an answer is a homogeneous mixture of one or more solutes. A not unusual instance of an answer is sugar cubes brought to a cup of tea or coffee.

Dissolution is the process where a solute in a gaseous, liquid or stable section dissolves in a solvent to shape an answer. Solubility is the maximum awareness of a solute that may dissolve in a solvent at a given temperature. at the most attention of solute, the solution is said to be saturated.

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There are two characteristics of molecules, one is geometry and other is shape. Shape is excluding lone pair surrounding the central element and geometry is including the lone pair. Therefore, the angle of the given molecule can be found out by VSEPR theory.

VSEPR stands for valence shell electron pair repulsions. VSEPR theory is used to predict the shape and geometry of molecules on the basis of valence electrons pairs that are present around the central element of the molecule.

According to VSEPR theory, Lone pair lone pair repulsion is greater than bond pair bond pair repulsion. There are so many limitations of VSEPR theory. There is a repulsion between bond pair electrons and lone pairs present on the central element.

a) bond angle is 180°

b)bond angle is 120°

c)bond angle is 107.28'

d)bond angle is 109.28'

Therefore, the angle of the given molecule can be found out by VSEPR theory.

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What are the following masses

Please complete the questions

The gravitational radius (Rg) of the black holes would be approximately; 4.0 Mʘ black hole: 0.00332179 miles, 10.0 Mʘ black hole: 0.00830584 miles, 25.0 Mʘ black hole: 0.0207646 miles, and 10^8 Mʘ black hole: 8,305.84 miles.

To calculate the Gravitational Radius (Rg) of a black hole, you can use the formula:

Rg = 2 × G × M

where Rg is gravitational radius, G is gravitational constant (approximately 6.67430 × 10⁻¹¹ m³ kg⁻¹ s⁻²), and M is mass of the black hole in solar masses (Mʘ).

Given that Rg is defined as 2 miles per solar mass (Mʘ), we can convert the result to miles using the conversion factor of 1 mile = 1.60934 kilometers.

Let's calculate the Rg for the different masses

For a 4.0 Mʘ black hole:

Rg = 2 × G × M = 2 × (6.67430 × 10⁻¹¹ m³ kg⁻¹ s⁻²) × 4.0

Rg = 5.33944 × 10⁻¹⁰ m = 0.00332179 miles

For a 10.0 Mʘ black hole:

Rg = 2 × G × M = 2 × (6.67430 × 10⁻¹¹ m³ kg⁻¹ s⁻²) × 10.0

Rg = 1.33486 × 10⁻⁹ m = 0.00830584 miles

For a 25.0 Mʘ black hole:

Rg = 2 × G × M = 2 × (6.67430 × 10⁻¹¹ m³ kg⁻¹ s⁻²) × 25.0

Rg = 3.33715 × 10⁻⁹ m = 0.0207646 miles

For a 10⁸ Mʘ black hole:

Rg = 2 × G × M = 2 × (6.67430 × 10⁻¹¹ m³ kg⁻¹ s⁻²) × (10⁸)

Rg = 1.33486 × 10¹⁰ m = 8,305.84 miles

Therefore, the gravitational radius (Rg) of the black holes would be approximately:

4.0 Mʘ black hole: 0.00332179 miles

10.0 Mʘ black hole: 0.00830584 miles

25.0 Mʘ black hole: 0.0207646 miles

10^8 Mʘ black hole: 8,305.84 miles

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--The given question is incomplete, the complete question is

"If the Gravitational Radius (Rg) of a black hole is 2 miles per solar mass (Mʘ), what would be the Rg  of the black holes with the following masses: A 4.0 Mo black hole? B 10.0 Mo black hole? C 25.0 Mo black hole? D 108 Mo black hole? "--

Answer:

Music has the ability to deeply affect our mental states and raise our mood. When we need it, music gives us energy and motivation. When we're worried, it can soothe us; when we're weary, it can encourage us; and when we're feeling deflated, it can re-inspire us.

Explanation:

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Answer:

As altitude increases, partial pressure of O2 increases. -

Explanation:

-As altitude increases, partial pressure of O2 increases. -As atmospheric pressure increases, available O2 increases. -As atmospheric pressure increases, partial pressure of O2 increases. Boyle's law states there is a direct relationship between the pressure and volume of a gas at a constant temperature.

The Fischer projection given here is for L-enantiomer and ketopentose. Option B is correct, as there is a ketone group present in the carbohydrate monomer. Carbohydrate can have an aldehyde or ketone as a functional group.

Carbohydrate monomer is a single unit that can either have an aldehyde functional group called aldose or a ketone functional group called ketose. Here in the given diagram, the monomer has a ketone group (C=O) and has five carbons, so it is considered a keto pentose. Carbohydrates are classified into L and D forms based on their OH group, and this L and D form differs from the "l" and "d" form (classified on the direction of movement around the plane polarized light).

Hence, this given diagram is L-enantiomer and keto pentose, which is option B.

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Taking into account the reaction stoichiometry, the percent yield of BaCO₃ is 81.07%.

In first place, the balanced reaction is:

BaCl₂ + Na₂CO₃ → BaCO₃ + 2 NaCl

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Molarity is a measure of the concentration of a solute in a solution and indicates the number of moles of solute that are dissolved in a given volume.

The molarity of a solution is calculated by:

molarity= number of moles÷ volume

In first place, you know:

Replacing in the definition of molarity:

0.500 M= number of moles of Na₂CO₃÷ 0.025 L

Solving:

number of moles of Na₂CO₃= 0.500 M× 0.025 L

number of moles of Na₂CO₃= 0.0125 moles

0.500 M= number of moles of BaCl₂÷ 0.025 L

Solving:

number of moles of BaCl₂= 0.500 M× 0.025 L

number of moles of BaCl₂= 0.0125 moles

This indicates that 0.0125 mol of Na₂CO₃ and 0.0125 mol of BaCl₂ are present.

Since the stoichiometric ratio of the reactants is 1:1, if 0.0125 mol of Na₂CO₃ and BaCl₂ are present, since the amounts are equal, it makes no difference to work with any of the reactants.

The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.

The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:

percent yield= (actual yield÷ theoretical yield)×100%

where the theoretical yield is the amount of product acquired through the complete conversion of all reagents in the final product, that is, it is the maximum amount of product that could be formed from the given amounts of reagents.

The following rule of three can be applied: if by reaction stoichiometry 1 mole of BaCl₂ form 1 mole of BaCO₃, 0.0125 moles of BaCl₂ form how many moles of BaCO₃?

moles of BaCO₃= (0.0125 moles of BaCl₂×1 mole of BaCO₃)÷ 1 mole of BaCl₂

moles of BaCO₃= 0.0125 moles

Being the molar mass of BaCO₃ 197.35 g/mole, the theoretical yield of BaCO₃ is calculated as:

theoretical yield of BaCO₃=  0.0125 moles× 197.35 g/mole

theoretical yield of BaCO₃= 2.466875 grams

In this case, you know:

Replacing in the definition of percent yield:

percent yield= (2 grams÷ 2.466875 grams)× 100 %

Solving:

percent yield= 81.07%

Finally, the percent yield for the reaction is 81.07%.

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Based on the concentration and pH of monoprotic acid, the Ka for the acid is 4.04 * 10⁻⁶.

Acids are defined as a substance that when dissolved in water produces hydrogen ions as the only positive ions in the solution.

The number of hydrogen ions that an acid produces per molecule of the solution is known as the basicity of the acid.

When an acid produces one mole of hydrogen ions per molecule of acid, the acid is said to be monobasic or monoprotic.

When an acid produces two moles of hydrogen ions per molecule of acid, the acid is said to be dibasic or diprotic.

The given acid is said to be monoprotic.

Let the monoprotic acid be HA.

The dissociation of HA in the solution is given as follows:

HA ⇄ H⁺ + A⁻

Ka = [H⁺] * [A⁻] / [HA]

[H⁺] = [A⁻]

The pH of the acid solution is 2.69

Hence

[tex][H^{+}] = 10^{-pH}[/tex]

[tex][H^{+}] = 10^{-2.69}[/tex]

[H⁺] = 0.00204

[A⁻] = 0.00204

[HA] = 1.03 M

Hence, Ka will be:

Ka = (0.00204 * 0.00204) / 1.03

Ka = 4.04 * 10⁻⁶

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Molarity (M) is the amount of a substance in a sure quantity of solution. Molarity is described because the moles of a solute according to liters of an answer. Molarity is also called the molar attention of an answer.

Calculation:-

mass = 0.600 g

the molar mass of NaNO₃ = 85 g

moles = 0.600/85

           = 0.007 moles

volume = 2 L

molarity = moles/volume

            = 0.007 /2

            = 0.035 M

Molar concentration is a measure of the attention of a chemical species, specifically of a solute in an answer, in terms of the amount of substance in step with the unit extent of the answer. In chemistry, the most generally used unit for molarity is the number of moles in keeping with liter, having the unit symbol mol/L or mol/dm³ in SI unit.

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The sample has a new pressure of 274kPa. If at 105 kPa and 275K, a 220 mL sample of helium gas is contained in a cylinder with a moving piston. The sample is pushed till it has a 95.0 mL volume and 310K .

The macroscopic characteristics of ideal gases are related by the ideal gas law (PV = nRT). A gas is considered to be perfect if its particles (a) do not interact with one another and (b) occupy no space (have no volume). Where P= pressure  V= volume and T = temperature.

From ideal gas equation

P₁V₁/T₁ =P₂V₂/T₂

105×220÷275 = P₂ ×95÷310

P₂= (105×220×310)÷(275×95)

P2= 7161000/26125

P2 = 274.105 kPa

Hence, the new pressure of helium gas is 274kPa

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Answer:

51.16% H₂O

Explanation:

To find the percent water in the hydrate, you need to

(1) calculate the masses of 7H₂O and MgSO₄ · 7H₂O

(2) calculate the percent composition

(Step 1)

Atomic Mass (Mg): 24.305 g/mol

Atomic Mass (S): 32.065 g/mol

Atomic Mass (O): 15.999 g/mol

Atomic Mass (H): 1.008 g/mol

Mass (MgSO₄): 24.305 g + 32.065 g + 4(15.999 g/mol) = 120.366 g

Mass (7H₂O): 14(1.008 g/mol) + 7(15.999 g/mol) = 126.105 g

Mass (MgSO₄·7H₂O): 120.366 g + 126.105 g = 246.471 g

(Step 2)

                                                Mass Water
Percent Composition  =  ----------------------------  x  100%
                                                Total Mass

                                                    126.105 g H₂O
Percent Composition  =  --------------------------------------  x  100%
                                          246.471 g MgSO₄·7H₂O

Percent Composition = 51.16% H₂O

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 0.25moles  of He are in a container with a volume of 5.6 L at STP.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

One mole of ideal gas has 22.4L volume at STP.

number of moles of Helium = Given volume ÷volume occupied by gas at STP

Given volume of helium = 5.6 L

Substituting all the given values, we get

number of moles of Helium = 5.6 L  ÷22.4L

number of moles of Helium =0.25moles

Therefore, 0.25moles  of He are in a container with a volume of 5.6 L at STP.

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Answer: 0.25 moles

Explanation:

Given volume of helium = 5.6 L

Substituting all the given values, we get

number of moles of Helium = 5.6 L  ÷22.4L

number of moles of Helium =0.25moles

Therefore, 0.25moles  of He are in a container with a volume of 5.6 L at STP.

Answer:

J.J. Thomson.

Explanation:

The credit for the discovery of the electron and its properties goes to J.J. Thomson based on his experiments carried out in a discharge tube. He suggested that electrons are necessary constituents of all atoms. J.J. Thomson carried out experiments by taking a gas at low pressure of 0.01mm Hg in a discharge tube.

Answer:

J.J. Thomson used a Crookes, or cathode ray, tube to conduct experiments that led to the discovery of the electron in 1897. He provided evidence that cathode rays have a negative charge. He also investigated positively charged neon gas particles.

Explanation:

The option that correctly describes a covalent species that has four electron groups around the central atom are:

It should be noted that when a molecule have four electron groups and it is been found around the central atom and this will orients the four groups in the direction of a tetrahedron.

However when there are  four atoms attached to these electron groups, in Tetrahedral Geometry, molecular shape  will also be also tetrahedral.

Instance of this is Methane (CH 4), in conclusion, in the case whereby all four electron pairs are bonding pairs, then it can be concluded that the  shape of the system is tetrahedral.

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missing options:

The ideal bond angle for a four-electron system is 109.5°.

If all four electron pairs are bonding pairs, the shape of the system is tetrahedral.

The eletron are not bonding in the system.

A bent shape is observed if there are two bonding pairs and two lone pairs.

The reaction used to prepare iodine in the laboratory is

2LiI(s)+2H₂SO₄(aq)+MnO₂(s)→Li₂SO₄(aq)+MnSO₄(aq)+I₂(aq)+2H₂O(l)

The oxidation state of Li in LiI is +1 and of I in LiI is -1.

The oxidation state of the element is defined as the number of electrons gained or lost by an element in the compound. Since Li is present in the 1st group of the periodic table and it contains one valence electron in it. It loses one electron to form Li⁺ ion. Hence, the oxidation state of Li in LiI is +1.

Iodine(I) element is present in the 17th group of the periodic table. It contains seven valence electrons in it and it requires one electron to complete its octet. When it gains one electron, it forms I⁻ ion. Hence, the oxidation state of I in LiI is -1

Therefore, the oxidation state of Li in LiI is +1 and of I in LiI is -1.

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Pour water into a graduated cylinder, measure the volume, submerge the object, and measure the volume again. The metal cylinder has a density of 0.1167.

These cylinders are used to test density and specific gravity. Smooth surfaces and meticulously turned ends. a collection of six various pieces in cylinder shape for density in electrical and thermal studies.

Weighing a metal object twice, once in air and once submerged in a liquid, yields the density of the metal, as described in the section The science behind density measurements.

An item of laboratory equipment known as a measuring cylinder, graduated cylinder, cylinder measurement, or mixing cylinder is used to measure the amount of liquids, chemicals, or solutions during routine lab work.

The object's volume can be calculated as the difference between the two volume measurements. The density of the object can now be determined by simply dividing the mass by the volume.

79.95 - 70.00 = 9.95

=9.95 ÷ 85.20

=0.1167

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Answer: 212

Explanation:

Answer:

36.132 × 10²³ atoms of Si

Explanation:

Formula we use,

→ No. of moles × 6.022 × 10²³

Now the atoms will be,

→ No. of moles × 6.022 × 10²³

→ 6 × 6.022 × 10²³

→ 36.132 × 10²³

There are 36.132 × 10²³ atoms.

The molecular or formula mass of each of the given substances is given below:

(a) P₄ = 128 amu

(b) H₂O = 18 amu

(c) Ca(NO₃)₂ = 124 amu

(d) CH₃CO₂H (acetic acid) = 60 amu

(e) C₁₂H₂₂O₁₁ (sucrose, cane sugar) = 342 amu

The molecular or formula mass of a substance id the sum of the masses of the atoms of the elements present in that substance.

The molecular or formula mass of each of the given substances is determined as follows:

(a) P₄ =  32 * 4

P₄ = 128 amu

(b) H₂O = 2 * 1 + 16

H₂O = 18 amu

(c) Ca(NO₃)₂ = 40 + (14 * 2 + 16 * 3 * 2)

Ca(NO₃)₂ = 124 amu

(d)  CH₃CO₂H = 2 * 12 + 4 * 1 + 16 * 2

CH₃CO₂H = 60 amu

(e) C₁₂H₂₂O₁₁  = 12 * 12 + 1 * 22 + 16 * 11

C₁₂H₂₂O₁₁ = 342 amu

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Consider the following mechanism.

The overall balanced chemical equation : 2O₃  ---->   3O₂

The intermediates within the mechanism : O

The order with respect to each reactant :  2

The rate law for the overall reaction : R = k[O₃]²/[O]

The equations are :

O₃  ---->   O₂  +  O   fast

O₃  +   O  --->  2O₃   slow

a) The overall reaction is given as :

2O₃  ---->   3O₂

b) The intermediates within the mechanism is O.

c)  The order with respect to each reactant is 2

d) slow step rate : k[O][O₃]

at equilibrium, kc = [O][O₂] / [O₃]

The rate law = R = k[O₃]²/[O]

Thus, Consider the following mechanism.

The overall balanced chemical equation : 2O₃  ---->   3O₂

The intermediates within the mechanism : O

The order with respect to each reactant :  2

The rate law expression for the reaction : R = k[O₃]²/[O]

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The binding energy per nucleon for the ¹⁹F nucleon is equal to 7.786 MeV/nucleon.

Binding energy can be defined as the minimum quantity of energy that is required to remove the particle from the system. Nuclear binding energy can be described as the energy required to dismantle a nucleus of an atom into free neutrons and protons.

The binding energy will be determined from the mass defect. Mass defect is calculated from the difference between the mass observed and the expected combined mass.

Given the mass of the ¹⁹F = 18.9984 a.m.u.

The mass defect for the ¹⁹F can be calculated as:

Δm = [tex](M _n +M_p) - M_F[/tex]

[tex]\triangle m =( 9\times 1.0078 + 10 \times 1.0087 )- 18.9984[/tex]

[tex]\triangle m =0.1588 \;a.m.u.[/tex]

The binding energy for the fluorine can be calculated as:

E = Δmc²

E = 0.1588 × 931.5

E = 147.92 MeV

The binding energy per nucleon of ¹⁹F can be calculated as:

B.E.N. = 147.92/18.9984 = 7.786 MeV per nucleon

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Answer:

The number of molecules of water us 1.50× 10²⁵ molecules

Explanation:

From N=nL

where L =avogadro number ( 6.02× 10^²³ entities)

The number of the molecules of water =1

n (amount of substance)=25 moles

hence (N) = 25×1×6.02×10^²³

=1.50×10²⁵ molecules of H2O

When sucrose is hydrolyzed, fructose and glucose will be created as the glycosidic linkage is broken. Hydrolyzed sucrose will give a positive Benedict's test. Hydrolysis can be achieved by adding dilute sulfuric acid.

Sucrose is a disaccharide sugar composed of glucose and fructose monomer units linked together by glycosidic bonds.

Because there are no free aldehyde groups, a sucrose molecule is not reducing.

Hydrolysis of sucrose yields fructose and glucose.

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The energy in the battery was transformed into electrical energy, light energy, and heat energy is the best explanation of the energy in the circuit (Option A).

The energy is conserved in a battery as chemical energy that can be used by converting it into electrical energy, a process that is well known to release heat.

Therefore, with this data, we can see that the energy conserved in a battery is a form of chemical energy that can be converted into electrical energy for use.

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Answer:

12.044×10^23

Explanation:

Molecular mass is the sum of atomic masses of the elements present in a molecule. 12 gram of carbon that is one mole contains

6.022×10^23 atoms

. It is called Avogadro's constant.

So, Number of particles = Given number of moles

×

Avogadro number.

Therefore, the number of atoms of He in 2.0 moles = 2.0× 6.022×10^23= 12.044×10^23

There are

12.044×10^23

atoms in 2.0 moles of Helium.

Answer:

12.044 × 10^23

Explanation:

Molecular mass is the sum of atomic masses of the elements present in a molecule. 12 gram of carbon that is one mole contains

6.022×10^23 atoms.

. It is called Avogadro's constant.

So, Number of particles = Given number of moles

×

Avogadro number.

Therefore, the number of atoms of He in 2.0 moles = 2.0×6.022×10^23 = 12.044×10^23

There are

12.044×10^23

atoms in 2.0 moles of Helium.

When 1-Chloropentane is treated with sodium ethoxide, it follows the SN2 mechanism. Therefore, option (1) is correct.

The SN2 reaction can be defined as a type of reaction mechanism where one bond is broken and one bond is formed in one step. "SN" refers that the reaction is a nucleophilic substitution and proceeds via a bi-molecular mechanism. Here, both the reacting chemical species are involved in the rate-determining step.

The reaction takes place at an aliphatic sp³ carbon center with an electronegative, stable leaving group attached to a halide atom. The breaking of the C-X bond and the formation of the new bond occur simultaneously via a transition state in which a carbon under nucleophilic attack will be pentacoordinate.

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