if you had a solution of an unknown ph and had to pick an indicator that you tested in your data, what indicator would be a good choice to use to determine the actual ph of the solution?

The concentration of the conjugate base at the equivalence point after the initial neutralization is 0.152 M. Then the answer is 0.152 M.

When titrating an acid with a base, we can determine the concentration of the conjugate base at the equivalence point using the equation MaVa = MbVb. So in order to reach the equivalence point in their titration, Sonni needed to add 19.42 ml of KOH to 20.00 ml of 0.309 M HF.

What is the concentration of the conjugate base at the equivalence point after the initial neutralization?SolutionWe can start by writing the balanced chemical equation for the reaction between KOH and HF:HF + KOH → KF + H2OSince the equation is balanced,

we can say that 1 mole of HF reacts with 1 mole of KOH to produce 1 mole of KF and 1 mole of H2O. Therefore, the moles of KOH added to the solution is equal to the moles of HF present initially:

moles of KOH = Molarity × Volume in liters

= 0.309 M × (19.42 / 1000) L

= 0.006007 Mmoles of HF

= Molarity × Volume in liters

= 0.309 M × (20.00 / 1000) L

= 0.00618 MSince the moles of KOH added is slightly less than the moles of HF present initially, the solution is still acidic, and there is still some HF remaining after the initial neutralization. At the equivalence point, all of the HF has reacted with KOH,

and the solution contains only KF and water. So, we can use the balanced chemical equation to calculate the number of moles of KF produced when all of the HF has reacted with KOH.

Number of moles of KF = 0.006007 mol

HF + KOH → KF + H2O1 mole HF produces 1 mole KF;

therefore, 0.006007 moles HF will produce 0.006007 moles of KF. The volume of the solution at the equivalence point is 19.42 ml + 20.00 ml = 39.42 ml = 0.03942 L.

Therefore, the concentration of KF at the equivalence point is:Concentration of KF = (0.006007 mol) / (0.03942 L)= 0.152 MFinally, we know that KF is the conjugate base of HF,  

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The boiling point of the 3.6 molal solution of ethylene glycol in benzene is 89.208 ºC.

What is Boiling Point?

Boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure, usually atmospheric pressure. At the boiling point, bubbles of vapor are formed throughout the liquid, and the liquid changes phase to become a gas.

The boiling point elevation of a solution is given by the formula:

ΔTb = Kb x molality

Where ΔTb is the boiling point elevation, Kb is the ebullioscopic constant of the solvent, and molality is the molal concentration of the solute.

For benzene, Kb = 2.53 ºC/m.

Since the molality of the ethylene glycol solution is 3.6 molal, we can calculate the boiling point elevation as:

ΔTb = 2.53 ºC/m x 3.6 molal = 9.108 ºC

This means that the boiling point of the solution is 9.108 ºC higher than the boiling point of pure benzene.

To find the boiling point of the solution, we need to add this value to the boiling point of pure benzene, which is 80.1 ºC. Therefore:

Boiling point of solution = 80.1 ºC + 9.108 ºC = 89.208 ºC

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Explanation:

1. Count each type of atom in reactants and products. ...

2. Place coefficients, as needed, in front of the symbols or formulas to increase the number of atoms or molecules of the substances. ...

3. Repeat steps 1 and 2 until the equation is balanced.

If you want to distinguish between the contents of two unlabeled cups, one containing Powerade White Cherry and the other containing Canada Dry Club Soda, you can use a pH indicator.

To impress your roommates with your chemistry skills, you need to select an indicator that can differentiate between the two based on their pH values. Powerade White Cherry has a pH of 2.8 while Canada Dry Club Soda has a pH of 5.2.

Looking at the table of pH indicators, there are two options that cover the pH range of both substances: Bromothymol blue and Phenolphthalein. However, Bromothymol blue has a pH range of 6.0-7.6, which is not low enough to detect the acidity of Powerade White Cherry.

Hence, choose Phenolphthalein, which has a pH range of 8.2-10.0, encompassing both 2.8 and 5.2. By using Phenolphthalein as an indicator, you can impress your roommates with your chemistry knowledge and successfully distinguish between the two cups.

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2.56 x 10²² propane molecules must be burned with 6.82 grams of oxygen.

The following is the balanced equation for propane combustion:

[tex]C3H8 + O2 = 3CO2 + 4H2O[/tex]

Hence, we require 5 oxygen molecules for every molecule of propane.

We must multiply the quantity of propane molecules by the ratio of oxygen molecules to propane molecules in order to determine how many oxygen molecules are needed to burn 2.56 x 1022 propane molecules.

[tex]O2[/tex] to [tex]C3H8[/tex] Ratio: 5:1

The necessary number of O2 molecules is (5/1) times 2.56, which equals 1.28 x 10²³.

So, using the molar mass of oxygen, we can convert the quantity of oxygen molecules to grams.

1 mole of [tex]O2[/tex] = 32 g

1.28 x 10²³ molecules of O2 = (1.28 x 10²³/ 6.022 x 10²³) moles of O2

Mass of [tex]O2[/tex] = (1.28 x 10²³/ 6.022 x 10²³) x 32 g.

Mass of [tex]O2[/tex] = 6.82 grams.

Hence, 6.82 grams of [tex]O2[/tex] are required to burn 2.56 x 10²² propane molecules.

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The substance tested is likely marijuana or related cannabis compounds if the Duquenois-Levine test turns purple.

In the event that the Duquenois-Levine arrangement becomes purple when added to an example, it recommends the presence of maryjane or other marijuana related substances.

The Duquenois-Levine test is a colorimetric test used to recognize the presence of weed in an example. It includes blending the example in with a progression of reagents, including Duquenois reagent and chloroform. Assuming the subsequent chloroform layer becomes purple, it proposes the presence of cannabinoids, which are the dynamic mixtures tracked down in cannabis.

It is essential to take note of that the Duquenois-Levine test isn't conclusive and can't be utilized to affirm the presence of maryjane all alone. All things considered, it is in many cases utilized as a fundamental screening test and might be circled back to other corroborative tests to give a more exact distinguishing proof.

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Photochemical oxidants are examples of secondary pollutants.

Photochemical oxidants are secondary pollutants as they are formed in the atmosphere due to the combination of primary pollutants, such as nitrogen oxides and volatile organic compounds, with sunlight. These oxidants can cause smog, respiratory problems, and other environmental issues.

The other options mentioned in the question are: Aerosols, volatile organic compounds, combustion gases, and dust from soil erosion are examples of primary pollutants.Aerosols are solid or liquid particles that are suspended in the air. They can come from natural sources like dust or volcanic ash, or human-made sources like industrial emissions.

Volatile organic compounds (VOCs) are organic chemicals that easily evaporate into the air. They are emitted by many sources such as motor vehicles, industrial processes, and household products.Combustion gases are produced by the burning of fossil fuels or biomass. They can contribute to smog and other environmental problems.Dust from soil erosion is also a primary pollutant, which can cause respiratory problems and contribute to air pollution.

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The classification of an acid or base as weak or strong is primarily determined by the extent of dissociation in water.

The characterization of a corrosive or a base as frail or solid not entirely set in stone by the degree of separation of the broke down corrosive or base, which is otherwise called the ionization steady. A solid corrosive or base totally separates in water, creating a high centralization of hydrogen or hydroxide particles, separately.

Conversely, a powerless corrosive or base just to some extent separates, bringing about a lower centralization of particles. The solvency of the corrosive or base and its fixation likewise assume a part in deciding its solidarity, however they are not the essential variables. The grouping of a corrosive or base is connected with its solidarity, yet not by any means the only element decides its solidarity.

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Specific heat capacity is a property of a material that represents the amount of heat required to change the temperature of one kilogram of the substance by one degree Celsius.

It is expressed in units of joules per kilogram per degree Celsius (J/kg°C).To find the specific heat capacity of a sample, you should divide its heat capacity by its mass. This distinction is important because specific heat capacity allows for the comparison of different materials' abilities to store thermal energy.

For example, if you have two different materials with the same mass, the one with the higher specific heat capacity will require more energy to heat it up by the same temperature difference. This will provide you with the amount of energy required to change the temperature of one kilogram of the substance by one degree Celsius.

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The correct answer is 8. To determine the number of hydrogen atoms (H) in (NH4)2CO3, we need to count the number of H atoms in each of the constituent ions and then multiply by the number of ions present in the formula.

The (NH4)2CO3 formula contains two ammonium ions (NH4+) and one carbonate ion (CO32-). Each ammonium ion contains four hydrogen atoms, while the carbonate ion contains no hydrogen atoms.

Therefore, the total number of hydrogen atoms in (NH4)2CO3 is:

2 ammonium ions x 4 hydrogen atoms per ammonium ion = 8 hydrogen atoms

Thus, the correct answer is 8.

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When silver nitrate and sodium chloride are combined with water, silver chloride will solidify and precipitate out of solution. In this instance, silver chloride is the precipitate.

Precipitation includes the following: rain, hail, sleet, and snow. Rain forms when water vapour in clouds condenses on dust particles, which eventually grow too big to stay in the cloud and fall to the ground, where they collect more water and enlarge further.

The chemical reaction between potassium chloride and silver nitrate, in which solid silver chloride precipitated out, is among the greatest examples of precipitation reactions. This precipitation reaction resulted in the formation of an insoluble salt.

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The rate constant is the quantity that describes the connection between the molar concentration of the reactants and the rate of the chemical reaction.

If the reaction is occurring throughout the volume of the solution, [A] and [B] are the molar concentrations of substances A and B in moles per unit volume of solution and the reaction rate constant varies on temperature.

The rate constant is denoted by the letter k.

Given data, BOD₆ = 213 mg/l

ultimate BOD = 318.4 MG/l = L

Assume temperature = 20° C

and t = 6 day

k = ?

BOD = L(1- [tex]e^{-kt}[/tex])

213 = 318.4 (1-[tex]e^{-k*6}[/tex])

[tex]e^{-k6}[/tex] = 0.331

Taking logs on both sides

-k*6 = -1.105

k = 0.1842 d⁻¹

≈ 0.184⁻²/day

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The molarity of a solution made by dissolving 51.6 grams of NaCl in enough water to make 650 ml of solution  is approximately 1.36 M

The molarity of a solution can be calculated using the formula:

Molarity (M) = (moles of solute) / (volume of solution in liters)

First, we need to convert the mass of NaCl (51.6 grams) to moles. To do this, we'll use the molar mass of NaCl, which is approximately 58.44 g/mol.

Moles of NaCl = (51.6 grams) / (58.44 g/mol) = 0.883 moles

Next, we'll convert the volume of the solution from milliliters (mL) to liters (L).

Volume of solution = 650 mL * (1 L / 1000 mL) = 0.65 L

Now, we can calculate the molarity of the solution using the formula.

Molarity (M) = (0.883 moles) / (0.65 L) = 1.36 M

Thus, the molarity of the solution made by dissolving 51.6 grams of NaCl in enough water to make 650 mL of solution is approximately 1.36 M (rounded to two decimal places).

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1. The C in the first structure should have four total valence electrons. To complete its octet, it thus requires 4 extra electrons. The molecule should thus have 8 + 2 = 10 valence electrons overall, yet 14 valence electrons are present in this configuration. Thus, this is not the proper Lewis structure.

2. While both elements' octets are full in the second form, the total valence electron is incorrect. Total valence electrons should be =7+6+1=14, with 7 coming from the 7 valence electrons of a Cl atom, 6 from the 6 valence electrons of O, and 1 from the negative charge. Yet, there are a total of 8 + 4 = 12 electrons in the structure, where 8 is for 4 lone pairs of electrons and 4 is from the double bond. Thus, it is likewise an improper Lewis structure.

3. The valence electron count in the N2 molecule, the third structure, is accurate. The N atom, however, has not yet reached octet. There are 6 electrons in each N. The two N atoms do not thus have an octet arrangement. Thus, it is not a valid Lewis structure.

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When a 0.005 mol HCl is added to the buffer solution containing 0.500 mol HF and 0.500 mol KF, it will use up one of the components and destroy the buffer solution.

A buffer solution is a chemical mixture that resists changes in pH by neutralizing small amounts of added acids or bases. It contains a weak acid and its conjugate base or a weak base and its conjugate acid.

Buffer solutions are necessary for many chemical processes since pH changes can dramatically affect the behavior of chemical compounds.

Buffer solutions can be prepared using a wide range of chemical compounds, and the exact composition of the solution is determined by the desired pH range and the concentration of the buffer components.

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If 10 ml of 0.05 m NaOH is introduced to a 20 ml solution of 0.1 m NaNO₂ and 0.1 m HNO₂, the pH of the resultant solution is 3.74.

The balanced chemical equation for the reaction between NaOH, NaNO₂, and HNO₂ is:

HNO₂ (aq) + OH⁻ (aq) → NO₂⁻ (aq) + H₂O (l)

Before any NaOH is added, the solution contains 20 mL of 0.1 M NaNO₂ and 0.1 M HNO₂. The HNO₂ is a weak acid, and its dissociation in water can be represented as follows:

HNO₂ (aq) + H₂O (l) ⇌ H₃O+ (aq) + NO₂⁻ (aq)

The acid dissociation constant (Ka) for HNO2 is 4.5 x 10⁻⁴ at 25°C.

Adding 10 mL of 0.05 M NaOH to the solution will result in the formation of 0.005 moles of OH-. The reaction between OH- and HNO₂ will consume some of the HNO₂ and form NO₂⁻ and H₂O. The amount of HNO₂ that reacts can be calculated using the balanced chemical equation:

1 mol HNO₂ reacts with 1 mol OH-

Therefore, the amount of HNO₂ that reacts is:

0.005 moles of OH- x (1 mol HNO₂ / 1 mol OH-) = 0.005 moles of HNO₂

The remaining amount of HNO₂ in the solution is:

Initial moles of HNO₂⁻ moles of HNO₂ that reacted = (0.1 mol/L x 0.020 L) - 0.005 mol = 0.002 mol

The amount of NO₂⁻ that forms is equal to the amount of HNO2 that reacted:

0.005 moles of HNO₂ = 0.005 moles of NO2-

The amount of H³O+ that forms can be calculated using the equilibrium constant expression for HNO₂:

Ka = [H³O+][NO₂⁻] / [HNO₂]

[H₃O⁺] = Ka x [HNO₂] / [NO₂⁻] = (4.5 x 10⁻⁴) x (0.002 mol) / (0.005 mol)

                                                = 0.00018 M

The pH of the solution can be calculated as:

pH = -log[H³O⁺] = ㏒(0.00018) = 3.74

As a result, the pH of the resulting solution is 3.74.

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A higher pH indicates a higher concentration of hydroxide in an aqueous solution containing a weak base. The correct answer is (A).

At much higher concentrations, acid A can be weaker than acid B, which is strong. As a result, A's pH is lower because it can still dissociate to produce more H+ in the solution.

pH is a proportion of how acidic/fundamental water is. The range is 0 to 14, with 7 representing neutrality. pH values below 7 indicate acidity, while pH values above 7 indicate a base. pH is a proportion of the overall measure of free hydrogen and hydroxyl particles in the water.

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Q- when looking at an aqueous solution of a weak acid, a lower ph corresponds to: select the correct answer below:

A. a higher concentration of hydronium

B. a lower concentration of hydronium

C. a higher concentration of hydroxide

D. a more dilute solution

The main causes of the Grevy's zebra population decrease are habitat degradation, competition for resources with domestic livestock, and hunting for their skins and meat.

The main factor contributing to the decrease of Grevy's zebras in Ethiopia is hunting. Although their striking skins are the main reason they are hunted, they are also rarely slain for food and, in some areas, for medicinal purposes.

Zebras from Grevy's are in peril. Grevy's zebras have experienced one of the greatest range reductions of any African animal, and are now restricted to northern Kenya and southern and eastern Ethiopia. They are no longer residing in Somalia, Eritrea, Djibouti, and it's possible that they've left Sudan as well.

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Answer:

  12.5 g/cm³

Explanation:

You want the density of a rock that has a mass of 125 g and displaces 10 mL of water in a graduated cylinder.

The balance shows a mass that is the sum of the readings on the different beams:

  20 +100 + 5 = 125

We presume the balance is measuring grams.

The graduated cylinder shows an increase in volume from 20 mL to 30 mL when the rock is added to the water. This means the rock has a displacement of ...

  30 mL -20 mL = 10 mL = 10 cm³

The density is found using the given formula:

  density = mass/volume

  density = (125 g)/(10 cm³) = 12.5 g/cm³

The density of the rock is 12.5 g/cm³.

Answer:

Answer and Explanation: Vapor pressure has an inverse relationship with intermolecular forces. This means that the stronger the intermolecular forces are, the lower the vapor pressure is.

Answer:

Explanation:

The intermolecular forces in carbon dioxide are weak, so its vapor pressure is relatively high.

The % by mass of aniline in the distillate is approximately 1.97%.

To find the % by mass of aniline in the distillate from a mixture of aniline and water steam distilled at normal atmospheric pressure with an initial temperature of 97.3°C and partial pressure of water at 745 mmHg, follow these steps:

Step 1: Determine the total pressure: Since normal atmospheric pressure is approximately 760 mmHg, the total pressure is 760 mmHg.

Step 2: Calculate the partial pressure of aniline: Subtract the partial pressure of water (745 mmHg) from the total pressure (760 mmHg) to get the partial pressure of aniline. Partial pressure of aniline = 760 mmHg - 745 mmHg = 15 mmHg.

Step 3: Find the mole fraction of aniline: Divide the partial pressure of aniline (15 mmHg) by the total pressure (760 mmHg) to get the mole fraction. Mole fraction of aniline = 15 mmHg / 760 mmHg = 0.0197368.

Step 4: Calculate the mass % of aniline in the distillate: The mole fraction represents the ratio of aniline to the total mixture. To find the mass %, multiply the mole fraction by 100. Mass % of aniline = 0.0197368 x 100 = 1.97368%.

So, the % by mass of aniline in the distillate is approximately 1.97%.

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Kinetic molecular theory states that there is no attractive and repulsive force between the gas molecules. So option (3) is false.

According to the kinetic molecular theory the gases are composed of a large number of particles that behave like hard, spherical objects in a state of constant which is in random motion. This theory states that the energy that an object has because of its motion. The Kinetic Molecular Theory can be explained as the forces between molecules and the energy that they possess. This is explained as a theoretical model which describes the molecular composition of the gas in terms of a large number of submicroscopic particles that includes atoms and molecules. This states that the gas pressure arises due to particles colliding with each other and the walls of the container.

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The complete question is,

Which of the following statements about the kinetic-molecular theory of gases is false?

1. the average kinetic energy of a gas molecule is independent of the temperature.

2. collisions between molecules are elastic.

3. Attractive and repulsive forces are present between gas molecule.

The coefficient of h in the balanced chemical equation above is 2.

When the skeleton equation above is balanced and all coefficients reduced to their lowest whole-number terms, the coefficient for h is 2.What is a skeleton equation?

A skeleton equation is an equation in which the reactants and products are listed using their chemical formulas but not their stoichiometric coefficients. A balanced chemical equation is one in which the stoichiometric coefficients for reactants and products are included in such a way that the law of conservation of mass is fulfilled,

and the number of atoms of each element present in the reactants equals the number of atoms of that element present in the products.For instance, a typical chemical equation, which shows the chemical reactants and products, can be represented as:

2 NaOH (aq) + H2SO4 (aq) → Na2SO4 (aq) + 2 H2O

(l)Here, the reaction involves two moles of sodium hydroxide, one mole of sulfuric acid, one mole of sodium sulfate, and two moles of water. To balance this equation,

the coefficients should be added as:2 NaOH (aq) + H2SO4 (aq) → Na2SO4 (aq) + 2 H2O (l)The balanced chemical equation represents the actual stoichiometric ratios of reactants and products in the chemical reaction.

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Being non-polar molecules, acetone and pentane interact by London dispersion forces. Option a is correct.

Both acetone and pentane are non-polar molecules and interact through London dispersion forces, which are the weakest type of intermolecular force and arise from temporary dipoles induced in the molecules.

Neither acetone nor pentane has a hydrogen atom bonded to a highly electronegative atom, which is necessary for hydrogen bonding. Ion-induced dipole interactions arise between an ion and a non-polar molecule, but neither acetone nor pentane is an ion. Dipole-dipole interactions occur between polar molecules, but acetone is a polar molecule and pentane is non-polar, so they cannot interact through this type of force. Hence option a is correct.

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--The complete question is, How acetone and pentane interact.
Choose one or more: a. london dispersion b. hydrogen bonding c. ion-induced dipole d. dipole-dipole--

the Clausius equation relates the change in entropy of a system to the heat flow and temperature at which the heat is transferred. This physical relationship reflects the fundamental principle that the entropy of a system tends to increase over time, and that heat flows spontaneously from hotter to cooler objects in order to achieve this increase in entropy.

The Clausius equation relates the change in entropy of a system to the heat flow and temperature at which the heat is transferred. It is given by:

ΔS = Qrev/T

where ΔS is the change in entropy of the system, Qrev is the amount of heat transferred reversibly between the system and its surroundings, and T is the temperature at which the heat is transferred.

To understand the physical basis of this equation, we need to consider the concept of entropy. Entropy is a measure of the disorder or randomness in a system. As a system evolves, it tends to move towards a state of maximum entropy, where its energy is spread out uniformly and there is no gradient or potential for further energy transfer. The second law of thermodynamics states that the entropy of an isolated system always increases over time, which implies that heat always flows spontaneously from hotter to cooler objects.

The Clausius equation relates this concept of entropy to the transfer of heat between a system and its surroundings. It tells us that the change in entropy of a system is proportional to the amount of heat transferred reversibly between the system and its surroundings, and inversely proportional to the temperature at which the heat is transferred. The term "reversible" refers to a process that can be reversed with infinitesimal changes to external conditions, so that the system and its surroundings return to their original states.

The physical relationship between the quantities in the Clausius equation can be understood as follows. The change in entropy of a system is related to the amount of heat transferred reversibly between the system and its surroundings, because heat flow is a key factor in determining the degree of disorder or randomness in a system. As heat flows from a hotter object to a cooler object, it tends to spread out and become more evenly distributed, which increases the entropy of the system. The temperature at which the heat is transferred is also important, because the higher the temperature, the greater the potential for heat to flow and increase the entropy of the system.

In summary, the Clausius equation relates the change in entropy of a system to the heat flow and temperature at which the heat is transferred. This physical relationship reflects the fundamental principle that the entropy of a system tends to increase over time, and that heat flows spontaneously from hotter to cooler objects in order to achieve this increase in entropy.
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The distance travelled by the chromatogram substance divided by the solvent front's travel distance yields the Rf (retention factor) value. Hence, the sample's Rf value is close to 0.7.

It is a dimensionless quantity that aids in the identification and description of substances separated by chromatography. A different technique that may be used to determine if a material is pure or impure is paper chromatography. Moreover, it may be used to separate mixtures of soluble chemicals in order to identify the components of the mixture.

They are frequently coloured materials like food colouring, ink, dye, or plant pigments. The Rf value in this situation may be determined using the formula below: Rf is equal to the sum of the distances covered by the substance front and the solvent front.

Rf = 4.2 cm ÷ 6.0 cm

Rf ≈ 0.7

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We need 1.08 mL of NaOH solution to reach a pH of 7.10.

To solve this problem, we need to use the balanced chemical equation for the neutralization reaction between phosphoric acid (H₃PO₄) and potassium hydroxide (KOH); H₃PO₄ + 3KOH → K₃PO₄ + 3H₂O

From the equation, we can see that one mole of H₃PO₄ reacts with three moles of KOH. Therefore, the number of moles of KOH required to neutralize 0.149 moles of H₃PO₄ is;

n(KOH) = 3 × n(H₃PO₄) = 3 × 0.149 mol = 0.447 mol

Next, we need to calculate the volume of 1.250 M KOH solution that contains 0.447 mol of KOH;

V(KOH) = n(KOH) / C(KOH) = 0.447 mol / 1.250 mol/L

= 0.358 L = 358 mL

So, 358 mL of 1.250 M KOH solution is required to neutralize the 0.149 moles of H₃PO₄.

Now, to reach a pH of 7.10, we need to add a strong base such as NaOH to the solution until the pH reaches the desired value. Since NaOH is a strong base, it will react completely with the remaining H₃PO₄ to form water and sodium phosphate (Na₃PO₄)

H₃PO₄ + 3NaOH → Na₃PO₄ + 3H₂O

To calculate the volume of NaOH solution required to reach a pH of 7.10, we need to know the initial pH of the solution. Assuming that the solution is initially acidic, we can use the Henderson-Hasselbalch equation to calculate the initial pH;

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

where pKa is the dissociation constant of H₃PO₄, [A] is the concentration of the conjugate base (H₂PO₄⁻), and [HA] is the concentration of the acid (H₃PO₄).

The pKa values for phosphoric acid are;

pKa₁ = 2.148

pKa₂ = 7.198

pKa₃ = 12.319

Since we are assuming that the solution is initially acidic, we can use the first dissociation constant (pKa1 = 2.148) to calculate the concentration of H₂PO₄⁻;

[H₂PO₄⁻] = [A] = K × [HA] / (K + [HA])

where K is the equilibrium constant for the dissociation of H₃PO₄:

K = [H⁺][H₂PO₄⁻] / [H₃PO₄]

At a pH of 7.10, [H⁺] = [tex]10^{-7.10}[/tex] = 7.94 × 10⁻⁸ M. Substituting this value into the equation for K and solving for [H₂PO₄⁻], we get:

K = 7.94 × 10⁻⁸ × [H₂PO₄⁻] / 0.149 M

[H₂PO₄⁻] = (K × 0.149 M) / 7.94 × 10⁻⁸

[H₂PO₄⁻] = 2.81 × 10⁻⁵ M

Now we can use the Henderson-Hasselbalch equation to calculate the initial pH:

pH = pKa₁ + log([A]/[HA])

= 2.148 + log(2.81 × 10⁻⁵ / 0.149)

= 1.08

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

"A solution made with 0.149 moles of phosporic acid (H₃PO₄) dissolved in 159mL of solution was titrated with 1.250 M KOH . How many mL of NaOH solution are necessary to reach a pH of 7.10?"--

Answer:

7 km/hr

Explanation:

rate = distance / time

Rate: in km/hr

Distance: 14 km

Time: 2 hr

Rate = 14 km / 2 hr

Rate = 7 km/hr

In this case, since the unmarked beaker contained a strong base, we can expect its pH to be greater than 7.

.
To determine the pH of the unmarked beaker before adding the acid, we need to understand the pH scale. The pH scale ranges from 0 to 14, with a pH of 7 being neutral, below 7 being acidic, and above 7 being basic.
Since we know the solution in the unmarked beaker was a strong base, it is likely to have a high pH value.

Common strong bases include sodium hydroxide (NaOH) and potassium hydroxide (KOH). The pH of these strong bases in a concentrated solution is typically between 12 and 14.
However, without additional information about the specific strong base and its concentration, it is impossible to give an exact pH value for the unmarked beaker.

In summary, we can conclude that the pH of the unmarked beaker before adding the acid was above 7, indicating a strong basic solution, but we would need more information to determine the exact pH value.

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The rate constant is 3.0 x [tex]10^{4} M^{-1} S^{-1}[/tex] which is calculated by using the  Arrhenius equation.

We can use the Arrhenius equation to find [tex](E_{a} / R)[/tex][([tex](1/ T_{2} ) - ( 1/ T_{1} )[/tex]] separately,

We have, Activation energy, [tex]E_{a}[/tex] = 30.0 kJ/mole = 30000 J/mole

R = 8.314 J/mole .K

Temperature T2 = 201.0C = 201.0 + 273 = 474 K

T1 = 172 C = 172 + 273 = 445 K

Hence,

{ [tex](E_{a} / R)[/tex][([tex](1/ T_{2} ) - ( 1/ T_{1} )[/tex] } = (30000/8.314) x [(1/474) – (1/445)]

[tex](E_{a} / R)[/tex][([tex](1/ T_{2} ) - ( 1/ T_{1} )[/tex] =  – 0.4961

Let us use this value and Rate constant  [tex]K_{2}[/tex] = 5.0 x 104[tex]M^{-1} S^{-1}[/tex] and have to solve it for [tex]K_{1}[/tex]

[tex]K_{1}[/tex] / (5.0 x 104) = e –0.4961.

[tex]K_{1}[/tex] / (5.0 x 104) = 0.6089

[tex]K_{1}[/tex] =  5.0 x 104 x 0.6089

[tex]K_{1}[/tex] = 3.0 x [tex]10^{4} M^{-1} S^{-1}[/tex]

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The complete question is,

The rate constant of a certain reaction is known to obey the Arrhenius equation, and to have an activation energy is 30.0 kJ/mole. if the rate constant of this reaction is at  5.0 x 104[tex]M^{-1} S^{-1}[/tex], what will the rate constant be at  172 C? round your answer to significant digits.