Please help me
Define acid.
Mention four products of destructive distillation of coal.
In a tabular, highlight two differences between diamond and graphite.
List four types of salt.
Outline two physical properties of a base.

Around 80.5 KJ

Multiply Heat of Fusion and Mass to get the q value.

The direction of the reaction, as written, spontaneous at 25 ∘C and standard pressure is reverse.

To calculate the value of Δ∘rxn at 25.0 ∘C, we can use the equation:

Δ∘rxn(T2) = Δ∘rxn(T1) + ΔH∘(products) - ΔH∘(reactants)

where;

Using the data from the table of thermodynamic properties, we can look up the enthalpy change of formation values for C2H4(g), H2O(l), and C2H5OH(l):

ΔH∘f(C2H4(g)) = 52.26 kJ/mol

ΔH∘f(H2O(l)) = -285.83 kJ/mol

ΔH∘f(C2H5OH(l)) = -277.69 kJ/mol

Substituting these values into the equation, we get:

Δ∘rxn(25.0 ∘C) = -44.2 kJ + (-277.69 kJ/mol) - (-52.26 kJ/mol)

Δ∘rxn(25.0 ∘C) = -44.2 kJ - (-277.69 kJ/mol) + 52.26 kJ/mol

Δ∘rxn(25.0 ∘C) = -44.2 kJ + 277.69 kJ/mol + 52.26 kJ/mol

Δ∘rxn(25.0 ∘C) = 233.23 kJ/mol

So the value of Δ∘rxn at 25.0 ∘C is 233.23 kJ/mol.

In which direction is the reaction, as written, spontaneous at 25 ∘C and standard pressure?

Since the value of Δ∘rxn at 25.0 ∘C is positive (233.23 kJ/mol), the reaction as written is not spontaneous at this temperature and standard pressure. The correct answer is "reverse."

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The standard change in Gibbs free energy of the reaction at 25 ∘C is -1.69 kJ/mol.

What is standard change?

To find the standard change in Gibbs free energy of the reaction, we need to use the following equation:

ΔG° = -RT ln(K)

where ΔG° is the standard change in Gibbs free energy, R is the gas constant (8.314 J/mol·K), T is the temperature in Kelvin (25 °C = 298 K), and K is the equilibrium constant.

To find K, we need to use the equilibrium partial pressures:

K = (PC × PD) / (PA × PB²)

where PA, PB, PC, and PD are the equilibrium partial pressures of A, B, C, and D, respectively.

Substituting the values, we get:

K = (5.47 atm × 5.63 atm) / (5.63 atm × (5.00 atm)²)

K = 0.6176

Now we can calculate the standard change in Gibbs free energy:

ΔG° = -RT ln(K)

ΔG° = -(8.314 J/mol·K) × (298 K) × ln(0.6176)

ΔG° = -1,690 J/mol or -1.69 kJ/mol

Therefore, the standard change in Gibbs free energy of the reaction at 25 ∘C is -1.69 kJ/mol.

What is free energy?

Free energy, also known as Gibbs free energy, is a thermodynamic quantity that represents the amount of energy in a system that is available to do work at a constant temperature and pressure. It is denoted by the symbol G and is expressed in units of joules (J) or calories (cal).

In simple terms, free energy is the energy that can be used to do work. It is defined by the equation:

ΔG = ΔH - TΔS

where ΔH is the change in enthalpy (heat content) of the system, ΔS is the change in entropy (disorder) of the system, and T is the absolute temperature in Kelvin.

If ΔG is negative, the reaction is spontaneous and can proceed without the input of external energy. If ΔG is positive, the reaction is non-spontaneous and requires energy input to proceed. If ΔG is zero, the system is at equilibrium.

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The sandwich contains approximately 71.25 grams of carbohydrates.

Calories are a unit of measurement used to quantify the amount of energy contained in food and beverages. The number of calories in a particular food is determined by the amounts of carbohydrates, fats, proteins, and other nutrients it contains.

To determine the number of grams of carbohydrates in the sandwich, we need to use the fact that carbohydrates, fats, and proteins have different calorie densities. Specifically, carbohydrates and proteins each contain about 4 calories per gram, while fats contain about 9 calories per gram.

First, let's calculate the total number of calories coming from the fat and protein in the sandwich:

Total calories = calories from carbohydrates + calories from fat + calories from protein

475 Calories = calories from carbohydrates + 10g x 9 Calories/g + 25g x 4 Calories/g

475 Calories = calories from carbohydrates + 90 Calories + 100 Calories

475 Calories - 190 Calories = calories from carbohydrates

285 Calories = calories from carbohydrates

Now that we know the number of calories from carbohydrates, we can use the calorie density of carbohydrates to determine the number of grams of carbohydrates:

285 Calories = carbohydrates in grams x 4 Calories/g

71.25 g = carbohydrates in grams

Therefore, the sandwich contains approximately 71.25 grams of carbohydrates.

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A concentrated saltwater solution weighing 29.97 g and fitting into a flask to the mark of 25.0 ml has a density of about 1199.2 g/L.

By dividing the solution's mass by its volume, we may get its density: density = mass/volume

We need to know the density of water at the solution's temperature as well as the capacity of the flask up to the 25.0 ml level in order to calculate the volume of the solution.

Since 1 mL = 0.001 L, volume is equal to 25.0 mL, or 0.0250 L.

Now, we may determine the solution's density as follows:

1199.2 g/L or 29.97 g/0.0250 L is what is referred to as density.

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The molecular formula of the compound, given that it contains 51.39% carbon, 8.64% hydrogen, and 39.97% nitrogen is C₆H₁₂N₄

To obtain the molecular formula, we must first determine the empirical formula. Details on how to obtain the empirical formula is given beloww:

Divide by their molar mass

C = 51.39 / 12 = 4.283

H = 8.64 / 1 = 8.64

N = 39.97 / 14 = 2.855

Divide by the smallest

C = 4.283 / 2.855 = 1.5

H = 8.64 / 2.855 = 3

N = 2.855 / 2.855 = 1

Multiply through by 2 to express in whole number

C = 1.5 × 2 = 3

H = 3 × 2 = 6

N = 1 × 2 = 2

Thus, we can conclude that the empirical formula is C₃H₆N₂

Finally, we shall determine the molecular formula. Details below

Molecular formula = empirical × n = mass number

[C₃H₆N₂]n = 140.22

[(12×3) + (1×6) + (14×2)]n = 140.22

70n = 140.22

Divide both sides by 70

n = 140.22 / 70

n = 2

Molecular formula = [C₃H₆N₂]n

Molecular formula = [C₃H₆N₂]₂

Molecular formula = C₆H₁₂N₄

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Answer: C)Deposition (gas to solid)

Explanation: According to the phase diagram, at room temperature (25°C) and 1 atm, the sample is in the gas phase.  As the temperature decreases to 80 K, it falls below the sublimation curve. T he sublimation curve represents the conditions at which a substance can change directly from a solid to a gas or from a gas to a solid without passing through the liquid phase.

Since the sample is in the gas phase at room temperature, cooling it to 80 K would cause it to go through the process of deposition, where the gas particles directly transform into a solid without first becoming a liquid.  This is indicated by the section of the phase diagram below the sublimation curve.

Component form of the vector v is as follows: 4 3 1.5 1 Using the standard basis vectors I and j), express the vector w as follows: 3 two 1 4 pp . 1 3 w 3.5 C. V plus w= d. Determine the vector v's magnitude

What does "vector" mean?

Latin word for "carrier" is "vector." Point A is transported to point B by vectors. The orientation of the vectors AB is the direction in which point A is moved in relation to point B, and the amplitude of the vector is the width of the line connecting the two locations A and B. The terms Euclidean vectors and spatial vectors are also used to refer to vectors.

A vector space is what?

A vector space, also known as a linear space, is a collection of things called vectors that can be added to and multiplied ("scaled") by figures called scalars in the fields of mathematics, physics, and engineering.

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To solve this problem, we can use the following equation that relates the pH of a solution to the acid dissociation constant (Ka) and the concentration of the acid:

pH = -log[H+]

where [H+] is the concentration of hydrogen ions in the solution.

(a) To find the Ka of the unknown acid, we need to first find the concentration of hydrogen ions in the solution. We can do this by taking the inverse of the pH and converting it to a concentration:

[H+] = 10^(-pH) = 10^(-3.56) = 2.17 × 10^(-4) M

The acid dissociation constant (Ka) can then be calculated using the equation:

Ka = [H+][A-]/[HA]

where [A-] is the concentration of the conjugate base of the acid and [HA] is the concentration of the undissociated acid. Since we don't know the values of these concentrations, we need to use the fact that the solution is 0.500 M to make an assumption about the degree of dissociation (α) of the acid:

α = [A-]/[HA]

Since the solution is not extremely dilute, we can assume that the degree of dissociation is small and that the concentration of the undissociated acid is approximately equal to the initial concentration of the acid. Therefore, we can write:

[A-] ≈ 0.500α

[HA] ≈ 0.500 - 0.500α

Substituting these expressions into the equation for Ka, we get:

Ka = [H+][A-]/[HA] ≈ ([H+][A-])/0.500α

≈ ([H+]/Ka)(0.500α)/(1-α)

Solving for Ka, we get:

Ka ≈ H+/0.500α

Substituting the values we have calculated, we get:

Ka ≈ (2.17 × 10^(-4))(1-α)/(0.500α) = 4.37 × 10^(-5)

Therefore, the acid dissociation constant of the unknown acid is approximately 4.37 × 10^(-5).

(b) To find the percentage of acid that is ionized in the solution, we can use the equation:

α = [A-]/[HA] = 10^(-pKa + pH)/(1 + 10^(-pKa + pH))

where pKa is the negative logarithm of the acid dissociation constant. Substituting the values we have calculated, we get:

α = 10^(-(-4.36) + 3.56)/(1 + 10^(-(-4.36) + 3.56)) ≈ 0.008

Therefore, the percentage of acid that is ionized in the solution is approximately 0.8%.

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To solve this problem, we can use the following equation that relates the pH of a solution to the acid dissociation constant (Ka) and the concentration of the acid:

pH = -log[H+]

where [H+] is the concentration of hydrogen ions in the solution.

(a) To find the Ka of the unknown acid, we need to first find the concentration of hydrogen ions in the solution. We can do this by taking the inverse of the pH and converting it to a concentration:

[H+] = 10^(-pH) = 10^(-3.56) = 2.17 × 10^(-4) M

The acid dissociation constant (Ka) can then be calculated using the equation:

Ka = [H+][A-]/[HA]

where [A-] is the concentration of the conjugate base of the acid and [HA] is the concentration of the undissociated acid. Since we don't know the values of these concentrations, we need to use the fact that the solution is 0.500 M to make an assumption about the degree of dissociation (α) of the acid:

α = [A-]/[HA]

Since the solution is not extremely dilute, we can assume that the degree of dissociation is small and that the concentration of the undissociated acid is approximately equal to the initial concentration of the acid. Therefore, we can write:

[A-] ≈ 0.500α

[HA] ≈ 0.500 - 0.500α

Substituting these expressions into the equation for Ka, we get:

Ka = [H+][A-]/[HA] ≈ ([H+][A-])/0.500α

≈ ([H+]/Ka)(0.500α)/(1-α)

Solving for Ka, we get:

Ka ≈ H+/0.500α

Substituting the values we have calculated, we get:

Ka ≈ (2.17 × 10^(-4))(1-α)/(0.500α) = 4.37 × 10^(-5)

Therefore, the acid dissociation constant of the unknown acid is approximately 4.37 × 10^(-5).

(b) To find the percentage of acid that is ionized in the solution, we can use the equation:

α = [A-]/[HA] = 10^(-pKa + pH)/(1 + 10^(-pKa + pH))

where pKa is the negative logarithm of the acid dissociation constant. Substituting the values we have calculated, we get:

α = 10^(-(-4.36) + 3.56)/(1 + 10^(-(-4.36) + 3.56)) ≈ 0.008

Therefore, the percentage of acid that is ionized in the solution is approximately 0.8%.

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It requires 10.15 kilojoules of energy.

The term "vaporisation" (or "evaporation") often refers to the transformation of a liquid's condition into a vapour phase below its boiling point. The phrase, however, can also refer to the process of removing a solvent, independent of the temperature used.

When a body moves to exert force, it is said to be exerting work. Energy is the capacity to accomplish work. Energy is something we always need, and it can take many different forms.

If the gold is present in the liquid state, you only have to determine the latent heat of vaporization, or lvap. The empirical data for gold is 330 kJ/mol.

Q = mlvap

Q = (2 kg)(1 kmol/197 kg)(1,000 mol/1 kmol)

Q = 10.15 kJ

It needs an energy of 10.15 kilojoules

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The concentrations of all species in a 0.510 M NaCH₃COO (sodium acetate) solution: [Na+]= 0.510 M , [OH-]= 1.8x10⁻⁵ M , [H₃O+]= 1.8x10⁻⁵ M , [CH₃COO-]= 0.510 M and [CH₃COOH]= 0.510 - (1.8x10⁻⁵) = 0.50982 M.

Concentration is the ability to focus your attention on a single task or thought for a prolonged period of time. It involves being able to ignore distractions and to be able to work through any difficulties or obstacles that may arise. Concentration is an important skill to master in order to achieve success in any endeavor, whether it be academic, professional, or personal. Good concentration can help you to stay focused, organized, and productive. When you are able to concentrate, you can take in the information needed to make better decisions and solve problems. Concentration is a skill that can be developed with practice, such as by setting goals, breaking down tasks into smaller, manageable pieces, and avoiding distractions.

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Answer:

Neutrons and Protons

Explanation:

Different elements can have subatomic particles of varying sizes. The size of an atom is defined by the size of its electron cloud, which is composed of electrons, and the size of its nucleus, which is composed of protons and neutrons. The atomic number and subsequently the identity of an element are determined by the number of protons in the nucleus. The quantity of protons and neutrons in the nucleus determines its size. The quantity of electrons in the electron cloud and the energy levels they are located at define its size. The size of atoms can differ depending on the element due to differences in the amount of protons, neutrons, and electrons.

The Ammonium Chloride solution at 0.25 M has a pH of 2.67.

As a result, the weak basic (Chlorine) in the solution is overpowered by the conjugate acid (Ammonium cation), making the solution mildly acidic. According to the equation pH =log[Hydrogen ion], an acidic solution has a pH lower than 7. Aqueous ammonium chloride solution has a pH that is less than 7.

Ammonium cation + Water ⇌ Nitrogen trihydride + Hydronium ion

Kb = [Nitrogen trihydride][Hydronium ion] / [Ammonium cation]

[Nitrogen trihydride] = [Hydronium ion] = x

[Ammonium cation] = 0.25 - x

Kb = [Nitrogen trihydride][Hydronium ion] / [Ammonium cation]

1.8 × 10–5 = x² / (0.25 - x)

1.8 × 10–5 = x² / 0.25

x² = 4.5 × 10–6

x = 2.12 × 10–3

pH = -log[Hydronium ion] = -log(2.12 × 10–3) = 2.67

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The elements that have an outer electron configuration of ms2nd2 are located in the d-block of the periodic table and include some of the transition metals and lanthanides.

To determine which elements in the periodic table have this outer electron configuration, you can look at the position of the d-block elements in the table. The d-block elements are located in the middle of the table and include the transition metals. These elements have partially filled d orbitals, which can accommodate up to 10 electrons.

Elements in the d-block with an atomic number of 21 through 30 (scandium through zinc) have an outer electron configuration of d10s2 and do not fit the ms2nd2 configuration. However, elements in the d-block with an atomic number of 39 through 48 (yttrium through cadmium) have an outer electron configuration of d10s2p1 and can have the ms2nd2 configuration by removing the single electron in the p orbital. Elements in the d-block with an atomic number of 57 through 80 (lanthanum through mercury) also have the possibility of having an outer electron configuration of ms2nd2.

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Answer:

Explanation:

dilute solutions of hydrochloric acid (HCl), sulphuric acid (H₂SO₄), and nitric acid (HNO₃) react with active metals to produce a salt and hydrogen gas.

Active metals react strongly and quickly with other elements and compounds due to the electrons in its structure and its ease of sharing the electrons with other elements.

The most active metals are found in Groups 1  and 2 of the Periodic Table (i.e. the left side), and include lithium, potassium, magnesium, and calcium. Metals such as aluminium, lead, and zinc, are less active than magnesium or calcium, but are generally still labelled as 'active'. Metals such as copper, gold, or silver are inactive and will not react.

Therefore, in the provided question, all the metals listed, except for copper, will produce a metal salt + hydrochloric acid. Copper will not react.

In general:

5,250. The number was rounded up from 5,249 because the last digit, 9, is greater than or equal to 5.

Rounding up is a mathematical operation that involves increasing a number to its nearest whole number. It is commonly used when dealing with money, measurements, or statistics. When rounding up, the number is increased to the next highest whole number. For example, if a number is 6.7, it would be rounded up to 7. Rounding up is often used when dealing with exact measurements or estimates to simplify the calculations. It can also be used to make the results of a calculation easier to understand. In the case of money, rounding up can be used to round a number to the nearest dollar. This prevents dealing with fractional amounts of money. Rounding up can also be utilized in statistical analysis, such as in the calculation of mean or median. This simplifies the data and prevents dealing with fractions or decimals.

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The maximum mass of carbon dioxide that could be produced from 6.9 g of octane and 42.2 g of oxygen is 21.3 g, rounded to 2 significant digits.

What is Octane?

Octane is a hydrocarbon with the chemical formula [tex]C_{8} H_{18}[/tex] It is an organic compound belonging to the alkane group, which means it consists of only carbon (C) and hydrogen (H) atoms bonded together by single covalent bonds. Octane is a colorless liquid with a molecular weight of approximately 114 g/mol and is commonly used as a component in gasoline or fuel for internal combustion engines.

From the balanced equation, we know that 1 mole of octane reacts with 12.5 moles of oxygen to produce 8 moles of carbon dioxide. Therefore, 0.0605 mol of octane would require 0.0605 mol x 12.5 = 0.75625 mol of oxygen to fully react.

Since we have only 1.32 mol of oxygen, which is in excess compared to the 0.75625 mol required by octane, oxygen is the excess reactant, and octane is the limiting reactant.

Now, we can use the stoichiometry of octane to carbon dioxide to calculate the maximum mass of carbon dioxide produced:

From the balanced equation, we know that 1 mole of octane produces 8 moles of carbon dioxide.

Molar mass of carbon dioxide (CO2) = 44.01 g/mol

Maximum moles of carbon dioxide produced from octane = 0.0605 mol x 8 = 0.484 mol

Maximum mass of carbon dioxide produced from octane = 0.484 mol x 44.01 g/mol = 21.3 g

Remember to round the final answer to 2 significant digits as requested.

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40 grams of KCl are dissolved in 100 mL of water at 45C. 5g of  additional grams of KCI are needed to make the solution saturated at 80 C as the solubility of KCl is 45g/ml

A uniform combination of a number of solutes within a solvent is referred to as a solution. One frequent illustration of a Solution is adding sugar cubes into your cup of tea and coffee. Solubility is the quality that makes sugar molecules more soluble.

In water, potassium chloride (KCl) dissolves. Its water solubility, like that of all other solutes, depends on temperature. The solubility of a salt increases as the solvent's temperature rises. This is fairly simple to experience with sugar. 40 grams of KCl are dissolved in 100 mL of water at 45C. 5g of  additional grams of KCI are needed to make the solution saturated at 80 C as the solubility of KCl is 45g/ml.

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3.0 moles of [tex]Al[/tex] can fully react with hydrogen chloride to produce 4.5 moles of [tex]H_{2}[/tex]. Thus, 0.93 moles will be produced by 0.62 moles of [tex]Al[/tex].

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The eutectic point is the lowest temperature at which the liquid phase is constant at a particular pressure.

A melting composition known as a eutectic consists of at least two components that melt and freeze at the same rates. The components combine during the crystallisation phase, operating as a single component as a result.

The eutectic is the system's lowest melting point under its own pressure; it has a matching temperature called the eutectic temperature and produces the eutectic liquid as a result. In terms of composition, eutectic liquids are located between the system's solid phases.

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The correct answer that represents beta decay is

In beta decay, a neutron in the nucleus is converted into a proton, and an electron (or beta particle) and an antineutrino are emitted from the nucleus.

In this case, a neutron in the 164Gd nucleus is converted into a proton, and an electron is emitted from the nucleus, resulting in the production of 164Tb.

Option A is not a valid representation of any known type of radioactive decay.

Option B represents alpha decay, in which an alpha particle is emitted from the nucleus.

Option C represents electron capture, in which an electron is captured by the nucleus.

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Enantiomers rotate the plane of polarized light in opposite directions, and this property is used to distinguish between them in a process called optical rotation.

Enantiomers are pairs of molecules that are non-superimposable mirror images of each other.

They are isomers, meaning they have the same molecular formula and connectivity but differ in their three-dimensional arrangement of atoms in space.

Enantiomers exhibit identical physical and chemical properties, except for their interaction with plane-polarized light (a type of light that oscillates in a single plane).

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The mass of calcium in the original urine sample would be 0.0140 g.

First, we need to find the masses of calcium and magnesium oxalates in the original sample. Let x be the mass of calcium oxalate and y be the mass of magnesium oxalate. Then we have:

x + y = mass of the mixed oxalate precipitate

Next, we need to use the information given to find the mass of calcium in the original sample. The mass of calcium oxide formed after ignition is equal to the mass of calcium oxalate in the original sample. We can calculate the mass of calcium oxide using the mass of calcium carbonate formed and the molar mass ratio of calcium carbonate to calcium oxide.

The balanced chemical equations for the reactions are:

CaC2O4 -> CaCO3 + CO2

CaCO3 -> CaO + CO2

The molar mass of CaCO3 is 100.09 g/mol, and the molar mass of CaO is 56.08 g/mol.

From the given information, we have:

0.0433 g = (x + y)(100.09 g/mol + 80.15 g/mol) / (128.10 g/mol + 80.15 g/mol)

0.0285 g = x(56.08 g/mol) + y(40.31 g/mol)

Solving these equations simultaneously, we get:

x = 0.0140 g

y = 0.0053 g

Therefore, the mass of calcium in the original sample (which is equal to the mass of calcium oxide formed after ignition) is:

0.0140 g

So the mass of calcium in the original sample is 0.0140 g.

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To draw the two circles, we would need to draw a smaller circle with a diameter of 2,532.5 miles (representing the moon) and a larger circle with a diameter of 75,974.4 miles (representing the Earth) that is 30 times larger than the smaller circle.

If we assume that the larger circle represents the Earth, then the diameter of the Earth would be 30 times the diameter of the smaller circle representing the moon. Let's say that the diameter of the smaller circle is x. Then the diameter of the larger circle (Earth) would be 30 times x or 30x.

To find the correct distance from Earth to the moon at this scale, we need to know the actual distance from Earth to the moon, which is approximately 238,855 miles or 384,400 kilometers. If we divide this distance by the scale factor of 30, we get:

238,855 miles / 30 = 7,961.8 miles

Therefore, the diameter of the smaller circle (moon) would be approximately 7,961.8 miles / π = 2,532.5 miles (rounded to one decimal place). And the diameter of the larger circle (Earth) would be 30 times that or 75,974.4 miles

So, to draw the two circles, we would need to draw a smaller circle with a diameter of 2,532.5 miles (representing the moon) and a larger circle with a diameter of 75,974.4 miles (representing the Earth) that is 30 times larger than the smaller circle.

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To calculate the cell potential, Ecell, for the given reaction at 298K, we need to use the Nernst equation. The Nernst equation relates the cell potential to the standard cell potential, temperature, and the concentrations of the reactants and products. The Nernst equation is given as follows:

Ecell = E°cell - (RT/nF) ln(Q)

where,

Ecell = cell potential

E°cell = standard cell potential

R = gas constant (8.314 J/K.mol)

T = temperature (298 K)

n = number of electrons transferred in the balanced redox reaction

F = Faraday constant (96,485 C/mol)

Q = reaction quotient

The given reaction is a redox reaction, which involves the transfer of two electrons from Co to Ag+. The balanced half-reactions are as follows:

Co(s) → Co2+(aq) + 2 e-

Ag+(aq) + e- → Ag(s)

The standard reduction potentials for these half-reactions are:

Co2+(aq) + 2 e- → Co(s) E°red = -0.28 V

Ag+(aq) + e- → Ag(s) E°red = +0.80 V

The overall standard cell potential can be calculated by subtracting the standard reduction potential of the anode from that of the cathode:

E°cell = E°red,cathode - E°red,anode

= +0.80 V - (-0.28 V)

= +1.08 V

Now we need to calculate the reaction quotient Q using the concentrations of the reactants and products. According to the given information, [Ag+] = 0.010 M and [Co2+] = 0.015 M.

Q = ([Co2+][Ag+]^2)/([Ag+]^2)

= ([0.015][0.010]^2)/([0.010]^2)

= 0.015 M

Substituting the values in the Nernst equation, we get:

Ecell = E°cell - (RT/nF) ln(Q)

= 1.08 - (8.314 x 298 / (2 x 96485)) ln(0.015)

= 0.829 V

Therefore, the cell potential, Ecell, for the given reaction at 298K is 0.829 V.

Answer:

-191 kJ

Explanation:

The given reaction is:

N₂(g) + 3H₂(g) → 2NH₃(g) ΔH = -76.4 kJ/mol

From the balanced equation, we can see that the stoichiometric ratio between hydrogen (H₂) and ammonia (NH₃) is 3:2. This means that 3 moles of hydrogen react to produce 2 moles of ammonia.

To determine the heat energy when 5.0 g of hydrogen (H₂) burns, we need to follow these steps:

Step 1: Calculate the moles of hydrogen (H₂)

Using the molar mass of hydrogen (H₂), which is 2 g/mol, we can calculate the moles of hydrogen (H₂) in 5.0 g of hydrogen:

Moles of H₂ = Mass of H₂ / Molar mass of H₂

Moles of H₂ = 5.0 g / 2 g/mol

Moles of H₂ = 2.5 mol

Step 2: Use the stoichiometry of the reaction

Based on the stoichiometry of the reaction, we know that 3 moles of hydrogen (H₂) react to produce 2 moles of ammonia (NH₃), and the enthalpy change (ΔH) is -76.4 kJ/mol.

Step 3: Calculate the heat energy

The heat energy for 2.5 moles of hydrogen (H₂) can be calculated using the given enthalpy change (ΔH) and the stoichiometry of the reaction:

Heat energy = Moles of H₂ x ΔH

Heat energy = 2.5 mol x -76.4 kJ/mol

Heat energy = -191 kJ (rounded to three significant figures)

So, the heat energy when 5.0 g of hydrogen (H₂) burns is -191 kJ (rounded to three significant figures), and the negative sign indicates that the reaction is exothermic, releasing heat.

The new volume of the helium sample would be 2.4 L.

According to the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the temperature in kelvins.

At STP (standard temperature and pressure), which is defined as 0°C (273.15 K) and 101.325 kPa, the volume of 2.0 liters of helium gas contains one mole of helium atoms.

To find the new volume of the helium sample when the temperature is increased to 27°C (300.15 K) and the pressure is decreased to 80 kPa, we can use the following equation:

(P1V1)/T1 = (P2V2)/T2

where P1, V1, and T1 are the initial pressure, volume, and temperature, respectively, and P2, V2, and T2 are the final pressure, volume, and temperature, respectively.

Plugging in the values, we get:

(101.325 kPa)(2.0 L)/(273.15 K) = (80 kPa)(V2)/(300.15 K)

Solving for V2, we get:

V2 = (101.325 kPa)(2.0 L)/(273.15 K) * (300.15 K)/(80 kPa) = 2.36 L

Therefore, the new volume of the helium sample is approximately 2.4 L (rounded to the nearest tenth).

More on gas laws can be found here: https://brainly.com/question/27009857

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