Evidence II
How did the suspects make the silver coins look gold?

Answer: 5.2

Explanation:

[tex]\text{pH}=-\log([\text{H}^{+}])\\\\=-\log(6.2 \times 10^{-6})\\\\=5.2[/tex]

The central idea is to combat malaria, typhus, and other insect-borne human diseases among both military and civilian populations.

The full form of DDT is Dichlorodiphenyltrichloroethane.

DDT is an insecticide used in agriculture. The United States banned the use of DDT in 1972. Some countries outside the United States still use DDT to control mosquitoes that spread malaria.

It also was effective for insect control in crop and livestock production, institutions, homes, and gardens. DDT's quick success as a pesticide and broad use in the United States and other countries led to the development of resistance by many insect pest species.

DDT is:

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0.1825 M is the concentration of H2SO4

To do this, let's write equation again:

Na2CO3 + H2SO4 ---------> H2O + CO2 + Na2SO4

As we can see, equation is already balanced and we can also see that mole ratio between the acid and the carbonate is 1:1, this means that moles of the acid, would be the same moles of carbonate, therefore, we can use the following expression:

M₁V₁ = M₂V₂ (1)

1: Is the carbonate

2: is the acid

To get the concentration of acid, we need to calculate the moles of carbonate used. This can be done using the molecular mass of sodium carbonate, which is 105.9888 g/mol, so the moles:

n₁ = 0.512/105.9888 = 0.0048 moles

Now that we have moles, we can use (1) and calculate the concentration of acid.

We know :

n₁ = M₁V₁ (2)

Replacing in (1) we have:

n₁ = M₂V₂

M₂ = n₁ / V₂ (3)

Now all we have to do is replace values and solve for concentration:

M₂ = 0.0048 / (0.02630) = 0.1825 M

This is concentration (molarity) of the H2SO4

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Compared to the circumference of the Earth Measured at the Equator, the circumference of the Earth measured through the poles is slightly smaller.

The circumference of a circle or sphere is the distance around the sphere or circle.

The circumference of the Earth varies from the equator to the North or South Poles.

The reason is that the shape of the earth is not completely spherical, but is elliptical.

Hence, at the North and South poles, the circumference of the earth is smaller than at the equator.

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Answer:

[tex]2.01x10^{21}atoms\ C[/tex]

Explanation:

First, find the atomic mass of carbon (12.01 [tex]\frac{g}{mol}[/tex]).  Then use this value and Avogadro's number ([tex]6.022x10^{23}[/tex]) to convert grams to atoms:

[tex]0.04g\ C(\frac{1\ mol\ C}{12.01\ g\ C})(\frac{6.022x10^{23} atoms\ C}{1\ mol\ C})=2.01x10^{21}atoms\ C[/tex]

Effective nuclear charge for Main Group elements would increases left to right across a period and decreases down a group.

Effective nuclear charge is the positive charge that nuclear protons have and that attracts valence electrons. Due to the shielding effect, the effective nuclear charge is always smaller than the total number of protons present in a nucleus.

Over time, effective nuclear charge increases but electron shielding stays the same. This draws the electron cloud closer to the nucleus, increasing the nuclear attraction to the outermost electron and making removal more difficult (requires more energy).

As we travel down the group, electrons are added to a new orbital, increasing the atomic size and decreasing the impact of the nucleus on the outermost electron, resulting in a lower value of the effective nuclear charge.

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A sample of gas has an initial volume of 5.6L at a pressure of 757mm Hg. If the volume of the gas is increased to 9.0L, then the pressure will be 438 mm Hg.

This empirical relationship, established in 1662 by physicist Robert Boyle, indicates that the pressure (p) of a given quantity of gas changes inversely with its volume (v) at constant temperature; in equation form, pv = k, a constant.

Given that,

initial volume (V₁) = 5.6 L

final volume (V₂) = 9.0 L

initial pressure (P₁) = 757 mm Hg

final pressure (P₂) = ?

As, we know

P₁V₁ = P₂V₂

now, putting the values:

757 mm Hg × 5.6 L = P₂ × 9.0 L

P₂ = 438 mm Hg

The pressure becomes:  438 mm Hg

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A 3828 mL flask is occupied by 4.89 g of a gas with a molar mass of 36.02 g/mol at 0.97 atm and 81.1 °C.

The mass of a sample of a chemical compound divided by the quantity, or number of moles in the sample, measured in moles, is known as the molar mass of that compound. The molar mass of a substance is a bulk attribute rather than a molecular one.

Step 1. Convert 81.7 °C to Kelvin.

We will use the following expression.

K = °C + 273.15

= 81.1 + 273.15

= 354.9 K

Step 2. Calculate the moles of the gas.

We will use the ideal gas equation.

P × V = n × R × T

n = P × V / R × T

n = 0.97 atm × 3.828 L / (0.08206 atm.L/mol.K) × 354.9 K

= 0.136 mol

Step 3. Calculate the mass of the gas.

The molar mass of the gas is 36.02 g/mol.

0.136 mol × 36.02 g/mol

= 4.89 g

Thus, A 3828 mL flask is occupied by 4.89 g of a gas with a molar mass of 36.02 g/mol at 0.97 atm and 81.1 °C.

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The required mass of the gas is 4.61 g.

The equation of state for a hypothetical ideal gas is known as the ideal gas law. Despite its many flaws, it is a good approximation of the behavior of several gases under various circumstances.

Given that the volume of the gas: V = 3828 mL = 3.828 L.

Pressure: P = 0.97 atm.

Temperature: T = 81.1 °C = (273+81.1) K = 354.1 K.

Then from ideal gas equation: PV = nRT

Where: R = universal gas constant = 0.082 atm L/mol.K

Required amount of gas: n = PV/RT

= (3.828*0.97)/(0.082*354.1) mol

= 0.13 mol.

Hence,  for a gas with a molar mass 36.02 g/mol, the mass of gas

= 0.13 mo l* 36.02 g/mol

= 4.61 g.

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The volume of KOH in the given reaction is 0.0052 L or 5.2 mL

Concentration is one of the most familiar and important parameters for those working with chemicals and reactions. It measures how much substance is dissolved in a given amount of solution. Chemists use a variety of units to express concentration. However, the term molarity, also known as molarity, is the most common way of expressing concentration. When reactants (compounds) are expressed in moles, chemical reactions can be expressed in whole numbers. This makes it easy to manipulate amounts.

Molarity describes the concentration of a solution. It is defined as the number of moles of substance or solute dissolved per liter of solution (not per liter of solvent!).

M₁V₁ = M₂V₂

Where, M₁ = Concentration of H₂SO₄ (0.11 M)

V₁ = Volume of of H₂SO₄ (0.0114 L)

M₂ = Concentration of KOH (0.24 M)

V₂ = Volume of KOH

Now, substitute the values:

0.11 × 0.0114 = 0.24 × V₂

V₂ = 0.0052 L or 5.2 mL

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[tex][\huge\color{cyan}\boxed{\colorbox{red}{ANSWER}}[/tex]

The Valence Shell Electron Pair Repulsion Model is often abbreviated as VSEPR (pronounced “vesper”).

It is basically a model to predict the geometry of molecules. Specifically, VSEPR models look at the bonding and molecular geometry of organic molecules and polyatomic ions. It is useful for nearly all compounds that have a central atom that is not a metal.

Explanation:

[tex]\small\color{red}\boxed{\colorbox{blue}{ BOARINGBOY}}[/tex]

The mass of water that should be produced from 54.8 L of hydrogen gas in the presence of excess oxygen at STP should be 36 grams.

The equation when hydrogen and oxygen gas combine to form water is written as:

[tex]2H_2 + O_2 -- > 2 H_2O[/tex]

From the equation of the reaction, the ratio of hydrogen gas that reacts to the water that is formed is 1:1.

At STP, 1 mole of a gas is equivalent to 22.4 L of the gas. Thus, 54.8 L of hydrogen will be equivalent to:

22.4 L = 1 mol

54.8 L = 54.8 x 1/22.4

            = 2 mol

With moles of hydrogen gas, 2 moles of water will also be formed.

Recall that: mass = mole x molar mass

The molar mass of water is 18 g/mol.

Thus, the mass of 2 moles of water can be calculated as:

Mass = 2 x 18

         = 36 grams

Thus, 36 grams of water will be formed when 65.8 L of hydrogen gas reacts with excess oxygen.

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The reaction supports the conservation of mass principle because the number of atoms of different elements before and after the reaction is balanced.

The law of conservation of mass states that mass can neither be created nor destroyed during the course of reactions. However, the mass can be converted into other forms during the course of reactions.

This law is extended to atoms and matters as well.

Thus, when you consider the equation highlighted:

[tex]2C + O_2 --- > 2CO[/tex]

One can see that there are 2 carbon atoms before and after the reaction. Also, there are 2 oxygen atoms before and after the reaction.

Thus, the equation is a balanced equation and a balanced reaction supports the law of conservation of mass, matter, or atoms.

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If the results of an experiment do not confirm the hypothesis, some information is still learnt about the hypothesis that is useful.

If your hypothesis is not confirmed by the experiment's findings, you should re-examine the data to see why your findings contradicted your hypothesis.

The first step you should take after a hypothesis is rejected is to carefully review the data. Afterward, give a possible explanation for why the hypothesis was erroneous using your study and data. Once a cause is identified, your hypothesis may have been incorrect.

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question:-

What is learned if the data from an experiment do not support the hypothesis?

A. Incorrect information; the data were not analyzed correctly.

B. Some information; the data still valuable information about the hypothesis.

C. No information; the data are bad or incomplete.

D. No information; the experiment is not useful.

The processes that converts chemical potential energy to heat is: C. Combustion of hydrocarbons, such as the methane in natural gas.

Boiling water is a necessary task for a variety of purposes, and natural gas is a powerful and reliable source of energy used for this purpose. Natural gas is a clean and efficient energy source that can be used to heat homes, water, and even cook food. It is also an environmentally friendly alternative to other energy sources, such as coal and oil, which are more harmful to the environment. This essay will discuss the benefits of utilizing natural gas for boiling water.

One of the primary advantages of using natural gas for boiling water is its affordability. Natural gas is a relatively inexpensive fuel source, and it is also easy to access. As a result, it is a cost-effective way to boil water, as it is more cost-effective than other fuel sources, such as electricity and propane. In addition, natural gas is a clean fuel source, as it does not generate any harmful emissions when burned. This makes it an ideal choice for boiling water, as it does not contribute to air pollution.

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The decreasing order for the boiling point will be: CH3CH2CH2CH2CH2CH2CH3 > CH3CH2CCH2CH3CH3 > CH3CH2CH2CH2CH2CH3CH3 > CH3CH2CH2CH3

Boiling point can be described as the temperature that is responsible for the conversion of liquid state to vapor state. The boiling point is dependent on the molar mass and branching. As all are alkanes, the force is the same.

As Heptane is the straight hydrocarbon has highest boiling point.

3,3-dimethylpentane has 7 carbon chained branched hydrocarbon, therefore, boiling point increased.

Hexane is straight hydrocarbon but has a low molecular weight, so the boiling point increased further.

As butane has 4 carbon straight chains, therefore it has the lowest boiling point.

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Note: the question given on portal is incomplete. Here is the complete question.

Question: The boiling points for a set of compounds in a homologous series can be qualitatively predicted using intermolecular force strengths. Using their condensed structural formulas, rank the homologous series for a set of alkanes by their boiling point. Rank from highest to lowest boiling point. To rank items as equivalent, overlap them.

a)CH3CH2CH2CH3

b) CH3CH2CH2CH2CH2CH3CH3

c) CH3CH2CCH2CH3CH3

d)CH3CH2CH2CH2CH2CH2CH3

Sudden increase in carbon pollution poses a threat to anybody utilizing a CO2 shooter in a constrained space. Because oxygen is replaced by Dioxide, an asphyxiant, more rapidly in a tiny space than in a larger one.

In order to stop a fire from spreading, smoke detectors use a substance to reduce the heat of the flames, smother the fuel, or cut off the oxygen supply. If used by a competent person, a portable fire suppression system may swiftly put out a minor fire.

Types of various classes of fire extinguishers. The six primary types of fire extinguishers are wet chemical, water, foam, Carbon dioxide, powder, and water mist.

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The final temperature of the water is equal to 67 °C.

The amount of heat required to heat the given amount of sample to a certain temperature can be calculated as:

Amount of absorption of heat = m ×S ×T

The final temperature of the mixture when two samples of different amounts and at different temperatures are mixed together is calculated as:

[tex]{\displaystyle T_f =\frac{m_1T_1+m_2T_2}{m_1+m_2}[/tex]

Given, the sample of water, m₁ = 26.7 g at temperature, T₁ = 26°C

The sample of water, m₂ = 41.7 g at temperature, T₁ = 93.7°C

The final temperature of the mixture will be:

[tex]{\displaystyle T_f =\frac{26.1 \times 26 + 41.7 \times 93.7}{26.7 + 41.7}[/tex]

T = 67°C

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One mole or 55.8 g of iron is required to produce one mole or 63.5 g of copper. Thus, mass of iron required to produce 258 Kg of copper is 215 Kg.

Copper is a transition metal which is a good thermal and electrical conductor. Copper sulphate reacts with metallic iron forming ferrous sulphate and copper metal as the reaction written here:

[tex]\rm CuSO_{4} + Fe \rightarrow FeSO_{4} + Cu[/tex]

Atomic mass of Fe = 55.8 g/mol

Atomic mass of Cu = 63.5 g/mol

As per the reaction 55.8 g or 0.05 Kg of Fe produces 0.06 Kg of Cu. Thus, mass of Fe needed to produce 258 Kg of Cu is:

= (258 Kg × 0.05 Kg) / 0.06 Kg

= 215 Kg.

Thus, 215 Kg of Fe is required to produce 258 Kg of copper.

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Considering the combined gas law, the final temperature of the ideal gas is -62.93°C.

Boyle's law states that the pressure of a gas in a closed container is inversely proportional to the volume of the container, when the temperature is constant.

The mathematical expression of this law is:

P×V= k

where:

Charles' law states that the volume of a gas in a closed container is directly proportional to the temperature, when the pressure is constant.

The mathematical expression of this law is:

V÷T=k

where:

Gay-Lussac's law states that the pressure of a gas in a closed container is directly proportional to the temperature, when the pressure is constant.

The mathematical expression of this law is:

P÷T=k

where:

Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:

(P×V)÷T=k

where:

Analyzing an initial state 1 and a final state 2, it is fulfilled:

(P₁×V₁)÷T₁= (P₂×V₂)÷T₂

In this case, you know:

Replacing in the combined gas law:

(4.62 atm× 35 L)÷ 260 K= (8.71 atm× 15 L)÷T₂

Solving:

[(4.62 atm× 35 L)÷ 260 K]×T₂= 8.71 atm× 15 L

T₂= (8.71 atm× 15 L)÷ [(4.62 atm× 35 L)÷ 260 K]

T₂= 210.07 K= -62.93 °C

Finally, the temperature is -62.93°C.

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The equilibrium constant of the redox reaction system is gotten as 3.67 * 10^11.

We know that the equation as it is a redox reaction.  We would need to obtain the standard electrode potential of the cell and use this information to get the free energy of the system. Then we can now substitute values to get the equilibrium constant.

Now;

ΔG = -nFEcell

ΔG =Change in free energy

n = Number of moles of electrons

F = Faraday's of electricity

Ecell = Cell potential

Ecell = 1.23 V - 0.770 V

= 0.46 V

Then;

ΔG = -(2 * 96500 * 0.46)

ΔG = -88780 kJ/mol

Now we have;

ΔG = -RTlnK

R = gas constant

T = temperature

K = equilibrium constant

-88780 = -(8.314 * 401 * lnK)

lnK =  -88780/ -(8.314 * 401)

lnK = 26.6

K = 3.67 * 10^11

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Answer:

C = 67%

O = 22%

H = 11%

Explanation:

Given C = 12, O = 16, H = 1

C8 = 8(12) = 96

O2 = 2(16) = 32

H16 = 16(1) = 16

Total molar mass = 96 + 32 + 16 = 144

% of C = 96/144 = 0.67 = 67%

% of O = 32/144 = 0.22 = 22%

% of H = 16/144 = 0.11 = 11%

The correct option is c)the volume of the NaOH solution used to reach the first equivalence point is twice the volume of NaOH used to go from the first equivalence point to the second equivalence point.  

A titration is a type of experiment that is used to determine the amount of a certain substance contained in a sample. A diprotic acid is an acid that can donate two protons (H+) per molecule. When performing a titration of a diprotic acid with NaOH, there are two equivalence points, or points when the number of moles of acid is equal to the number of moles of base.

The first equivalence point occurs when all of the acids have been neutralized, while the second equivalence point occurs when the excess base has been neutralized.   The volume of NaOH solution used to reach the first equivalence point is twice the volume of NaOH used to go from the first equivalence point to the second equivalence point.

This is because, for each mole of acid, two moles of the base are required to reach the first equivalence point, while for each mole of acid, only one mole of the base is required to reach the second equivalence point. Therefore, twice as much base is required to reach the first equivalence point compared to the second equivalence point. The volume of the beaker used in the titration does not affect the amount of NaOH used to reach either the first or second equivalence point.

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Student combines a solution of NaCl (aq)with a solution of AgNO₃ (aq), and a precipitate forms evidence that ionic bonds formed during the precipitation is The precipitate has a high melting point. The correct answer is C.

Ions with opposing charges join together to create ionic bonds. The strong electrostatic forces of attraction between the oppositely charged ions cause them to melt at a high temperature.

In ionic or aqueous solutions, the precipitation reaction takes place. Since the ions actively participate in the reaction and produce the product, precipitation reactions are also referred to as ionic reactions. Temperature, solution concentration, buffer solution, and other factors all affect how these reactions behave.

Precipitates are the insoluble salts created during precipitation reactions. Precipitation reactions are often double displacement events that result in the formation of the precipitate, a solid form of residue.

Ionic linkage. If an atom receives electrons, it becomes a negatively charged ion (cation), but if it loses them, it becomes a positively charged ion (cation) ( anion ). Following is a quick discussion on ionic bonds. To learn more, go to chemical bonding: the ionic bonding process.

Your question is incomplete but most probably your full question was

A student combines a solution of NaCl(aq)NaCl(aq) with a solution of AgNO3(aq)AgNO3(aq), and a precipitate forms. Which of the following is evidence that ionic bonds formed during the precipitation?

A) The resulting solution is colorless.

B) The resulting solution conducts electricity.

C) The precipitate has a high melting point.

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it's Gram because why not

Hello, Tia! Mass is measured in kilograms or grams. It tells the amount of matter in an object.

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The final equation is PCl3(aq) → PCl4-(aq) + Cl-(aq)

(a) All tetrafluoride compounds listed are non-polar. This is due to the symmetrical distribution of electrons all around the central atom, as shown by the Lewis electron point structure.

SiF4:

F

|

F-Si-F

|

F

SF4:

F

|

S-F

|

F

XeF4:

F

|

Xe-F

|

F

(b) The ascending order of melting points for the listed compounds is as follows:

SnF2< SeF2< KrF2. This is because the intermolecular force increases as the size of the atom increases. SnF2 has the smallest atoms. In other words, it has the weakest intermolecular forces and the lowest melting point. Since SeF2 has slightly larger atoms, it has slightly stronger intermolecular forces and a higher melting point. KrF2 has the largest atom, the strongest intermolecular forces and the highest melting point.

(c) The carbon-oxygen bonds of the oxalate ion (C20%) are all the same as the central carbon atom is attached to her two oxygen atoms and both of these bonds are double bonds . The Lewis electron point structure of the oxalate ion is:

O=C=O

(d) When PCl3 is dissolved in a polar solvent, the solution conducts electricity because the PCl3 molecules in the solution dissociate into ions. The dissociation process is represented by the following chemical formula:

PCl3(aq) → PCl4-(aq) + Cl-(aq)

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For use with fires involving common combustibles, flammable liquids, and powered electrical equipment, an extinguisher with an ABC rating is appropriate.

Monoammonium phosphate, a dry chemical, is used in ABC Fire Extinguishers to quickly put out a variety of fires by smothering the flames. All three types of fire can be extinguished using this light yellow powder: Paper, wood, and rubbish are all in Class A. Gases and liquids fall under Class B. Oil, textiles, paper, liquid, and electrical fires can all be extinguished with dry chemical fire extinguishers. This is the best fire extinguisher to keep on hand so that you can put out various fires quickly and safely. There are mostly two kinds: ABE The types A, B, and E are handled.

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Option(A) clear and calm  is the most likely forecast for California.

What is forecasting in climate?

Climate predictions anticipate weather averages and other climatic features from a few weeks to a few years in advance. Forecasters are increasingly making such predictions using detailed models of the Earth's climate system.

How would you describe California weather?

The majority of California has a Mediterranean-like climate, with warm, dry summers and moderate, rainy winters. The typical daily high temperature on the coast is approximately 70°F and higher, but can occasionally reach 80°F or more on the warmest summer days; freezing temperatures are uncommon, even in January.

Hence Option(A) is a correct answer.

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The offered assertion claims that a mixture of the aqueous solutions of KCl and NaO will result in the formation of a precipitate.

The word "aqueous" in an equation denotes a substance that is disseminated in fluids (a solution in water). For instance, sodium chloride aqueous solution is produced by adding sodium hydroxide solution to diluted hydrochloric acid. When liquid is used to describe a reaction, liquid substances are formed.

Liquids that are practically incompressible are classified as liquids, whereas aqueous liquids are those in which water serves as the solvent. This is the main distinction between liquids and aqueous fluids. Electrolytes are a sort of liquid as a result.

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If the reactants of a reaction are HCI and NaOH, Na₂CO3 be a product.HCl and NaOH are the reactants.

The chemical reaction between being an acid and a base is quite frequent. Water and a binary or ternary salt are the only byproducts of this reaction, which is also known as a neutralization or double replacement reaction.

For this issue, HCl serves as the acid and NaOH serves as the base.

NaOH + HCl →NaCl + H2O.

Neutralization Reactions

A very significant family of chemical reactions known as neutralisation reactions occurs when the effect or action of an acid is neutralised by the a base and vice versa. As a result of their reaction, an acid and a base produce heat as well as salt and water. Water is actually created through neutralisation reactions between the acid proton from of the acid as well as the base's hydroxyl group (H+ and OH- combine to make H2O). The quantities of the person to be taken depend on the amounts of the base and acid.

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Answer:

Explanation:

I did the lab