For the partially completed Lewis structures, pick the correct Lewis structure.





How many Valence Electrons total overall?

Answer:

Explanation:

2-bromopropane is the major product because the reaction mechanism involves the formation of the most stable carbocation intermediate. When hydrogen bromide reacts with propene, the hydrogen atom from HBr adds to the carbon atom of the double bond that has fewer hydrogen atoms attached, resulting in the formation of a carbocation intermediate. The intermediate can either form 1-bromopropane or 2-bromopropane depending on the position of the carbocation. The 2-bromopropane is the major product because the secondary carbocation formed in this case is more stable than the primary carbocation formed in the case of 1-bromopropane.

To test for an alkene, bromine water can be used. When an alkene reacts with bromine water, the bromine molecule adds across the double bond, forming a colorless dibromoalkane product. The mechanism for the reaction between hex-1-ene and bromine involves the formation of a cyclic bromonium ion intermediate, followed by the attack of water on the intermediate, resulting in the formation of the dibromoalkane product.

a) Addition polymerization is a process in which unsaturated monomers are joined together to form a polymer. The process involves breaking the double bond of the monomer and joining the monomers together to form a long-chain polymer. The process requires a catalyst to initiate the reaction.

b) The repeating unit of the polymer formed from the addition polymerization of chloroethene monomers is -CH2-CHCl-. This polymer is called polyvinyl chloride (PVC), and it has a wide range of uses, including pipes, electrical cables, and vinyl flooring.

A scientific theory is a well-tested explanation for a widely accepted hypothesis.

A scientific theory is a coherent statement or set of ideas that explains observed facts or phenomena and correctly predicts new facts or phenomena not previously observed, or which sets out the laws and principles of something known or observed.

In summary, a theory is a hypothesis confirmed by observation or experiment.

A body of facts that have been repeatedly confirmed through observation and experiment is said to be a theory.

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The statement that can definitely be inferred from the observation that the temperature rises when a solution of CaCl2 is dissolved in water is  Option III is correct.

The interactions between the species in solution are stronger compared to those in the separate solute and solvent. To analyze this problem, we need to consider the entropy of the system, which is related to the disorder or randomness of a system. The entropy of a system can be calculated by measuring the energy that must be supplied to the system to return it to its original state.
When the CaCl2 is dissolved in water, the entropy of the system increases because of the increase in the randomness of the system. This increase in entropy leads to a rise in temperature. Because the interactions between the species in solution are stronger than those in the separate solute and solvent, this suggests that the entropy of the system for this process is positive. The interactions in the separate solute and solvent are weaker than those between the species in solution.
Therefore, the statement that can definitely be inferred from the observation that the temperature rises when a solution of CaCl2 is dissolved in water is  Option III.

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The enthalpy change can not be measured directly because you have to take into account how much energy was put into the reaction in the first place.

Hope this helps!!! :)

The standard enthalpy of formation of all elements in their standard states are assumed to be zero. It is not possible to determine the enthalpy of formation of calcium carbonate as it is formed from other compounds.

The standard enthalpy of formation of a compound can be defined as the enthalpy change accompanying the formation of one mole of the compound from its constituent elements, all the substances being in their standard states.

The standard enthalpy of formation is usually denoted as ΔfH⁰. For example the enthalpy of formation of CO₂ and CH₄ are -393.5 kJ mol⁻¹ and -74.8 kJ mol⁻¹ respectively.

Here CaCO₃ is formed by the reaction:

CaO + CO₂ → CaCO₃

The enthalpy change for the given reaction is not an enthalpy of formation of CaCO₃. Since CaCO₃ is not formed from its constituent elements.

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The characteristics of combination and decomposition reactions are as follows:

Combination reactions are chemical reaction where two or more elements or compounds combine to form a single compound.

Decomposition reaction is a reaction in which chemical species such as chemical compounds break up into simpler parts or elements. Usually, decomposition reactions require energy input i.e. endothermic.

Combination reactions give off energy as heat when compounds are formed by joining bonds i.e. they are exothermic.

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a. The position function when the initial velocity 68.6 m/s  is s(t)=s0+v0t-1/2gt2.

b. The  highest point is 151.2m.

a. the velocity and position functions for an object fired vertically upward with an initial velocity of 68.6 m/s and an initial position of 30 m can be found using the equations v(t)=v0-gt and s(t)=s0+v0t-1/2gt2. Here, v0 is the initial velocity, s0 is the initial position, g is the acceleration due to gravity (9.8 m/s2), and t is time.
b. the time at which the highest point of the trajectory is reached can be found by setting the velocity to 0 and solving for t in the equation v(t)=v0-gt. This yields a time of t=v0/g. For the given initial velocity of 68.6 m/s, this yields t=6.97 s. The height of the object at the highest point of the trajectory is found by substituting t into the equation s(t)=s0+v0t-1/2gt2. For the given initial position of 30 m and initial velocity of 68.6 m/s, this yields s(6.97) = 30+68.6*6.97-1/2*9.8*6.97^2 = 151.2 m.

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The completed table of maximum moles of water, limiting reactant and excess reactant is as follows:

Q: 6 moles, O₂, 1 mole H₂

R: 6 moles, O₂, 2 moles H₂

S: 5 moles, none, none

T: 5 moles, H₂, 2.5 moles O₂

U: 8 moles, H₂, 2 moles O₂

The mole ratio of the reaction of hydrogen and oxygen to form water is obtained from the equation of the reaction.

The equation of the reaction is given below:

2 H₂ + O₂ --> 2 H₂O

The mole ratio of hydrogen to oxygen is 2:1 in both the water molecule and the reactants, hydrogen gas (H2) and oxygen gas, as can be seen from the balanced equation (O2). 

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In the circulatory system, the heart and blood vessels collaborate to move blood and the nutrients it carries around the body. The tissues in the heart include cardiac muscle tissue, connective tissue and so on.

Tissues are groups of similar cells that perform a common function, while organs are collections of tissues that work together to perform a specific function or set of functions. In the context of the heart, the tissues that make up the heart include cardiac muscle tissue, connective tissue, and nerve tissue, among others. These tissues work together to form the various structures of the heart, such as the chambers, valves, and blood vessels.

Therefore, the relationship between tissues and organs can be described as one where tissues form the building blocks of organs. Without the specialized functions of tissues, organs would not be able to perform their essential functions.

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The percent ionization of the nitrous acid in the 0.036 M aqueous solution is 2.1%.

The osmotic pressure (π) of a solution can be related to the molar concentration (M) of the solute and the temperature (T) of the solution by the following equation:

π = MRT

Where R is the gas constant.

We can use this equation to calculate the molar concentration of the nitrous acid solution:

M = π / RT

M = (0.93 atm) / (0.0821 L·atm/(mol·K) x 298 K)

M = 0.036 M

This is the molar concentration of the undissociated nitrous acid in the solution. To calculate the percent ionization of the acid, we need to know the concentration of the H+ and NO2- ions in the solution.

The balanced chemical equation for the dissociation of nitrous acid is:

HNO2(aq) ⇌ H+(aq) + NO2-(aq)

Let x be the extent of ionization of the nitrous acid. Then the concentration of H+ and NO2- ions can be expressed in terms of x as follows:

[H+] = x M

[NO2-] = x M

The concentration of the undissociated nitrous acid is (1-x)M.

The expression for the equilibrium constant (Ka) of the reaction can be written as:

Ka = [H+] [NO2-] / [HNO2]

Substituting the concentrations in terms of x, we get:

Ka = x^2M / (1-x)M

Simplifying the above equation, we get:

Ka = x^2 / (1-x)

The percent ionization of the acid is the fraction of the original HNO2 molecules that dissociate into H+ and NO2- ions. It can be calculated as follows:

% ionization = (concentration of H+ ions) / (initial concentration of HNO2) x 100

% ionization = (x M) / (M) x 100

% ionization = x x 100

Substituting the value of x from the above equation for Ka, we get:

Ka = x^2 / (1-x)

x = sqrt(Ka / (1+Ka))

We can calculate the value of Ka using the standard reference value of the acid dissociation constant (Ka) for nitrous acid at 25°C, which is 4.5 x 10^-4.

x = sqrt(4.5 x 10^-4 / (1+4.5 x 10^-4))

x = 0.021

% ionization = 0.021 x 100

% ionization = 2.1%

Therefore, the percent ionization of the nitrous acid in the 0.036 M aqueous solution is 2.1%.

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The formation of the phosphorylated intermediate (an anhydride) involves the formation of a penta-coordinate intermediate. This intermediate is formed by a nucleophilic attack of the sulfur on the phosphorus atom of the phosphate group.

In this mechanism, the sulfur atom of the sulfate group nucleophilically attacks the phosphorus atom of the phosphate group to form a penta-coordinate intermediate. This intermediate then rearranges to form a phosphorylated intermediate, which is an anhydride.

Mechanism showing the penta-coordinate intermediate and the formation of the phosphorylated intermediate are given as follows:

Step 1: Alkyl Phosphate Formation : The first step of the mechanism includes the formation of an alkyl phosphate. A proton is abstracted by OH− from the phosphate group to create the alkyl phosphate. The base catalyzes this step.

Step 2: Binding to Mg2+After the alkyl phosphate is created, the magnesium ion binds to it.

Step 3: Nucleophilic attack: Following that, the nucleophilic attack happens, with the nucleophile being the water molecule. It is coordinated with the magnesium ion. It occurs at phosphorus, causing it to be phosphorylated. It results in the creation of a pentacoordinate intermediate.

Step 4: Release of Orthophosphate: Orthophosphate is released as a result of the reaction between pentacoordinate intermediate and water. It results in the creation of a diester intermediate.

Step 5: Subsequent Hydrolysis: In the final step, the intermediate diester is hydrolyzed to form orthophosphate and the final product. This is accomplished via nucleophilic substitution.

The end result is a free phosphate group that is bound to the alcohol's oxygen. A phosphate anhydride is formed in the process.

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The heat transferred to the surroundings is 644 J.

First, we need to calculate the heat absorbed by the solution, qrxn.

The reaction that takes place is:

AgNO₃(aq) + NaOH(aq) → AgOH(s) + NaNO₃(aq)

The balanced equation tells us that 1 mole of AgNO₃ reacts with 1 mole of NaOH to produce 1 mole of AgOH. The heat absorbed by the solution is given by:

qrxn = -mCΔT

where;

Since the volume of the solution is given in mL, we can convert it to g using its density:

m = Vρ = (59 mL + 65 mL) x 1.00 g/mL = 124 g

ΔT = 24.91 oC - 23.68 oC = 1.23 oC

qrxn = -124 g x 4.184 J/goC x 1.23 oC = -644 J

Note that the negative sign indicates that the reaction is exothermic and releases heat.

Next, we need to calculate the heat transferred to the surroundings, qsurr. Since the calorimeter is an isolated system, we know that:

qrxn = -qsurr

Therefore:

qsurr = 644 J

Note that the positive sign indicates that the heat is transferred to the surroundings, as expected for an exothermic reaction.

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Answer:

The correct answer is:

(1) decreases 1 pH unit

(a) one radial node the Number of radial nodes = n - l - 1

And number of angular nodes = l

n = 3 and l = 1

Orbital is 3p.

(b) It has zero angular node hence s-orbital and there is 1 radial node . 1 = n - 0 - 1 ; n = 2 and l = 0

The orbital is 2s.

(c) the shape of the orbital is that of dz². There is two angular nodes and there is no radial node.

n = 3 and l = 2

Hence the orbital is 3dz².

In atomic physics, a radial node is a point in space where the probability density of finding an electron in an atom is zero. It is a type of nodal plane that occurs in atomic orbitals, which are regions of space where electrons are most likely to be found.

Radial nodes occur in the radial distribution function of an atomic orbital, which describes the probability density of finding an electron at a given distance from the nucleus. The number of radial nodes in an atomic orbital is equal to n - l - 1, where n is the principal quantum number and l is the azimuthal quantum number.

Radial nodes represent regions of space where the radial wave function of the electron changes sign.

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The notation provided appears to represent a nuclear reaction. Specifically, it represents the formation of radioactive carbon-14 in the upper atmosphere through the reaction of nitrogen-14 and a cosmic ray particle. The notation can be interpreted as follows:

- The symbol on the left side of the equation (Box+ eta mathcal PI ^ 9) represents a nitrogen-14 atom with a mass number of 14 and atomic number of 7 (since nitrogen has 7 protons). The superscript η indicates that the nitrogen atom is bombarded with a cosmic ray particle (represented by the box symbol) and undergoes a nuclear reaction. The subscript 9 indicates the total number of nucleons (protons and neutrons) in the nitrogen atom.

- The arrow in the middle of the equation (←) indicates that a nuclear reaction is taking place.

- The symbol on the right side of the equation (u I ^ 0 +N mathcal P I ^ L) represents a carbon-14 atom with a mass number of 14 and atomic number of 6 (since carbon has 6 protons) and a hydrogen atom. The superscript 0 indicates that the carbon atom is neutral (has no charge). The superscript L indicates that the carbon atom is radioactive and will decay over time.

Overall, the notation represents the nuclear reaction that occurs when a cosmic ray particle collides with a nitrogen-14 atom in the upper atmosphere, resulting in the formation of a carbon-14 atom and a hydrogen atom.

Na, or sodium, is the right response. Among the listed elements, sodium has the lowest IE1 value. The energy needed to remove one electron from a neutral atom when it is in the gaseous form is known as the first ionisation energy (IE1).

A soft, silvery-white, highly reactive metal that is a member of the periodic table's alkali metal family is sodium (Na). Its atomic mass is 22.99 and it has an atomic number of 11. Sodium is a crucial element used in many processes, such as making alloys, chemicals, and electrical parts. It is a frequent component of table salt (NaCl) and other nutritional sources and is also a necessary element for living things. In the human body, sodium regulates fluid balance, nerve transmission, and muscle contraction. However, consuming too much salt has been related to a number of illnesses, such as high blood pressure and cardiovascular disease.

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Option (C) is correct. The pH of the solution of sodium acetate (NaCH3COO) given that the Ka of acetic acid (CH3COOH) is 2.57.

Sodium acetate is defined as the salt of a weak acid and strong base from the equation:

C2H3NaO2 ---> CH3COO−+Na+

CH3COO− + H2O  ⇌  CH3COOH + OH−

As it is a weak acid and strong base, this is a good indicator of a fairly high pH value.

Kb = [HB+] + [OH−] / [B]

where, [B] is the concentration of the base[HB+] is the concentration of base ions.[OH−] is the concentration of the hydroxide ions.

Ka Kb=1⋅10−14

So, Kb=1⋅10−14 / 1.8⋅10−5

          =5.555...⋅10−10

Putting the value of this in the expression of pH we get the value of pH .

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Explanation:

a. homogeneous equilibrium (all species are in the gas phase)

b. heterogeneous equilibrium (solid carbon is present)

c. heterogeneous equilibrium (solid catalyst may be present)

d. heterogeneous equilibrium (liquid mercury and solid mercury(II) oxide are present)

Answer:

70.95%

Explanation:

To calculate the percent yield of water in this reaction, we need to compare the actual amount of water produced to the theoretical amount of water that could be produced based on the amount of hydrobromic acid and sodium hydroxide used.

First, we need to determine the limiting reactant. The limiting reactant is the reactant that is completely consumed in the reaction, limiting the amount of product that can be formed.

To find the limiting reactant, we can use stoichiometry to calculate the amount of water that could be produced from each reactant, assuming they react completely. The balanced chemical equation for the reaction is:

HBr + NaOH → NaBr + H2O

From the equation, we can see that the mole ratio of HBr to H2O is 1:1, and the mole ratio of NaOH to H2O is 1:1. Therefore, the amount of water produced depends on the amount of HBr and NaOH present, and the reactant that produces less water is the limiting reactant.

Using the molar masses of the compounds, we can convert the masses of HBr and NaOH to moles:

moles of HBr = 17.0 g / 80.91 g/mol = 0.210 moles

moles of NaOH = 13.9 g / 40.00 g/mol = 0.348 moles

Based on the balanced chemical equation, the theoretical amount of water that could be produced from 0.210 moles of HBr is also 0.210 moles. The theoretical amount of water that could be produced from 0.348 moles of NaOH is also 0.348 moles.

However, since the amount of water produced is given as 2.69 g, we need to convert this to moles:

moles of H2O produced = 2.69 g / 18.02 g/mol = 0.149 moles

To calculate the percent yield of water, we can use the formula:

percent yield = (actual yield / theoretical yield) x 100%

where actual yield is the amount of water produced (0.149 moles) and theoretical yield is the amount of water that could be produced based on the limiting reactant.

Since the reactant that produces less water is the limiting reactant, we need to compare the theoretical yield of water from both reactants, and the lower value will be the theoretical yield based on the limiting reactant.

The theoretical yield of water from HBr is:

0.210 moles of HBr x (1 mole of H2O / 1 mole of HBr) = 0.210 moles of H2O

The theoretical yield of water from NaOH is:

0.348 moles of NaOH x (1 mole of H2O / 1 mole of NaOH) = 0.348 moles of H2O

Since the theoretical yield of water from HBr is lower, it is the limiting reactant. Therefore, the theoretical yield of water is 0.210 moles.

Now we can calculate the percent yield of water:

percent yield = (actual yield / theoretical yield) x 100%

percent yield = (0.149 moles / 0.210 moles) x 100%

percent yield = 70.95%

Therefore, the percent yield of water is 70.95%.

Answer:

Assign an oxidation state to each element in each reaction and use the change in oxidation state to determine which element is being oxidized and which element is being reduced.

1. C6H12O6(s)+6O2(g)→6CO2(g)+6H2O(g)

2. C2H4(g)+Cl2(g)→C2H4Cl2(g)

Explanation:

1- In the reaction, C6H12O6(s)+6O2(g)→6CO2(g)+6H2O(g), the oxidation state of each element changes as follows:

C6H12O6: C: -1 to +4; H: +1 to +1; O: -2 to -2

O2: O: 0 to -2

CO2: C: +4 to +4; O: -2 to -2

H2O: H: +1 to +1; O: -2 to -2

2- In this reaction, oxygen (O2) is being reduced, since its oxidation state changes from 0 to -2. Carbon (C6H12O6) is being oxidized, since its oxidation state changes from -1 to +4.

In the reaction, C2H4(g)+Cl2(g)→C2H4Cl2(g), the oxidation state of each element changes as follows:

C2H4: C: -3 to -2; H: +1 to +1

Cl2: Cl: 0 to 0

C2H4Cl2: C: -2 to -2; H: +1 to +1; Cl: 0 to -1

In this reaction, chlorine (Cl2) is being reduced, since its oxidation state changes from 0 to -1. Ethene (C2H4) is being oxidized, since its oxidation state changes from -3 to -2.

The correct electron configuration for Tc (technetium) is [Kr] 5s² 4d⁵. Therefore, the correct answer is: [kr]5s²4d⁵.

Technetium (Tc) is a radioactive chemical substance with the atomic number 43 and symbol Tc. It is a silvery-gray metal that belongs to the transition metals group on the periodic table. Technetium is the first element to be artificially produced, and all of its isotopes are radioactive, with no stable isotopes. It is a highly toxic and dangerous element, and therefore has no significant commercial applications. Technetium has many nuclear and medical applications due to its radioactivity, and is used in medical imaging, cancer treatment, and scientific research.

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Answer:

C

Explanation:

edg 2023

We can calculate the mass of NaH2PO4·H2O required mass of NaH2PO4·H2O = (0.00250 - 5.5 x 10⁻⁻⁷)

Sodium dihydrogen phosphate NaH2PO4 (monobasic) and sodium hydrogen phosphate Na2HPO4 (dibasic) are a weak acid and its conjugate base pair that are mixed to make a buffer with pH 7.2.

To calculate the amount of solid NaH2PO4·H2O required to prepare the buffer, we need to use the Henderson-Hasselbalch equation:

pH = pKa + log([A-]/[HA])

First, we need to calculate the pKa of phosphoric acid (H3PO4). The dissociation reactions for phosphoric acid are:

H3PO4 ⇌ H+ + H2PO4-

[tex]Ka1 = 7.5 x 10^-3[/tex]Ka1 = 7.5 x 10^-3

H2PO4- ⇌ H+ + HPO42-

[tex]Ka2 = 6.2 x 10^-8[/tex]

HPO42- ⇌ H+ + PO43-

[tex]Ka3 = 4.8 x 10^-13[/tex]

pKa2 = -log(Ka2)

[tex]pKa2 = -log(6.2 x 10^-8) = 7.21[/tex]

[tex][A-]/[HA] = 10^(pH - pKa)[/tex]

[A-]/[HA] = 10^(2.14 - 7.21) = 1.1 x 10^-5[tex][A-]/[HA] = 10^(2.14 - 7.21) = 1.1 x 10^-5[/tex]

H3PO4 ⇌ H+ + H2PO4-

moles of H3PO4 = (0.1000 M) x (0.02500 L) = 0.00250 mol

moles of NaH2PO4·H2O = 0.00250 - x

The molar mass of NaH2PO4·H2O is 138.01 g/mol, so the mass of NaH2PO4·H2O required is:

mass of NaH2PO4·H2O = (0.00250 - x) mol x (138.01 g/mol)

Now, we can use the ratio of [A-] to [HA] to solve for x:

[A-]/[HA] = [NaH2PO4·H2O]/[H3PO4]

[tex]1.1 x 10^-5 = x / (0.05000 L x 0.100 M)[/tex]

x = 5.5 x 10^-7 mol[tex]x = 5.5 x 10^-7 mol[/tex]

Finally, we can calculate the mass of NaH2PO4·H2O required:

mass of [tex]NaH2PO4·H2O = (0.00250 - 5.5 x 10^-7)[/tex].

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The correct reaction equation is; Sr(OH)2 ----> Sr + 2OH

A correct chemical reaction equation must follow the law of conservation of mass, which states that matter cannot be created or destroyed, only transformed from one form to another. This means that the total number of atoms of each element on the reactant side of the equation must be equal to the total number of atoms of each element on the product side.

To ensure that an equation is correct, you should first check that the chemical formulas of the reactants and products are correct. You can then balance the equation by adjusting the coefficients in front of each chemical formula so that the number of atoms of each element is the same on both sides of the equation.

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The correct fraction that  can be used for the mole ratio to determine the mass of Cl2 from a known mass of AlCl3 is 2/2.

The mole ratio is a way of expressing the ratio of the number of moles of one substance in a chemical reaction to the number of moles of another substance in the same reaction.

Mole ratio is determined by the stoichiometry of the reaction, which is the quantitative relationship between the amounts of reactants and products in a chemical equation. The coefficients in a balanced chemical equation represent the mole ratios of the reactants and products in the reaction.

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Missing parts;

Read the following chemical equation.

Al + Cl2 → AlCl3

Which of the following fractions can be used for the mole ratio to determine the mass of Al from a known mass of AlCl3?

A. 2/1

B. 3/2

C. 2/2

D. 2/3

Answer:

6. The light being reflected off changes the color shown

7. The bottom, the sugar looses its positive charge

Explanation:

D. Directly scaling to the top of the mountain. The person would end up with the same potential energy or height regardless of the method they use to reach the top of the mountain because the end result is the same: they are at the top.

Potential energy is energy that is stored in an object due to its position relative to other objects, stresses within itself, electric charge, or other factors. When the object is moved or the stresses are released, energy is converted to kinetic energy, which is the energy of a moving object.

Therefore, if they take the switchback trail, parachute out of a plane, teleport using Star Trek technology, or directly scale to the top, they will have the same potential energy or height by the time they reach the top.

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Explanation: the resistance that one surface or object encounters when moving over another.

or

the action of one surface or object rubbing against another.

Answer: a force that resists the motion of one object against another