You add a Mg pellet weighing 0.085 g to 7.52 mL of 3 M HCl contained in a foam calorimeter and measure a temperature change of 41.5 oC. What is delta Hrxn in kJ/mol ?

Answers

Answer 1

Answer: A 0.86 mol sample of a substance is burned in a bomb calorimeter with a heat capacity of 11.23 kJ/C. The temperature increases by 14.93 C. What is ΔHrxn (in kJ/mol) for the combustion of the substance? Note: please record answer to two decimal places regardless of sig figs


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According to the law of entropy, when hot and cold objects meet, heat flows from hotter to colder. What would be the end result of mixing hot water and cold water?
Responses


A.The molecules in the cold water would slow down.The molecules in the cold water would slow down.


B.The cold water would continue to heat up.The cold water would continue to heat up.


C.All the water would reach an equilibrium temperature and heat would stop flowing.All the water would reach an equilibrium temperature and heat would stop flowing.


D.The two volumes of water would balance out but the temperature of the two would keep fluctuating.The two volumes of water would balance out but the temperature of the two would keep fluctuating.


E.The warm water would continue to cool down.

Answers

C. All the water would reach an equilibrium temperature and heat would stop flowing.

When hot and cold water are mixed together, heat flows from hotter to colder until both reach a common temperature. This is because the molecules in the hotter water have more kinetic energy than those in the colder water, and so they transfer some of their energy to the colder water until both have the same amount of energy. Eventually, all the water in the mixture will reach the same temperature, and heat transfer will stop. Therefore, the end result of mixing hot and cold water would be that all the water would reach an equilibrium temperature and heat would stop flowing.

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An unknown gas occupies 14.3L at a pressure of 30atm. What is the volume when the pressure is increased to 54atm?

Answers

Boyle's Law-

[tex]\:\:\:\:\:\:\:\:\:\:\:\star\:\sf \underline{ P_1 \: V_1=P_2 \: V_2}\\[/tex]

(Pressure is inversely proportional to the volume)

Where-

[tex]\sf V_1[/tex] = Initial volume[tex]\sf V_2[/tex] = Final volume[tex]\sf P_1[/tex] = Initial pressure[tex]\sf P_2[/tex] = Final pressure

As per question, we are given that -

[tex]\sf V_1[/tex] = 14.3L[tex]\sf P_1[/tex] =30atm[tex]\sf P_2[/tex] = 54 atm

Now that we have all the required values and we are asked to find out the final volume, so we can put the values and solve for the final volume -

[tex]\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\star\:\sf \underline{ P_1 \: V_1=P_2 \: V_2}[/tex]

[tex]\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf 30 \times 14.3= 54\times V_2\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\longrightarrow \sf V_2 = \dfrac{30 \times 14.3 }{54}\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\longrightarrow \sf V_2 = \cancel{\dfrac{ 429}{54}}\\[/tex]

[tex]\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf V_2 =7.944..........\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\longrightarrow \sf \underline{V_2 = 7.94 \:L }\\[/tex]

Therefore, the volume will become 7.94 L when the pressure is increased to 54 atm.

A gas at 49.3 °C and 893 mm Hg
experiences a temperature
change and ends up with a
volume of 778 mm Hg.

What is the new temperature of the gas?

[?] °C

Answers

Question :-

A gas experiences a temperature of 49.3 °C and a pressure of 893 mm Hg. By changing the pressure If it is increased to 778 mm Hg, what is the new temperature of the gas?

Solution :-

Gay-Lussac's Law-

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf \underline{ \dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}}\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf \dfrac{T_2}{P_2} = \dfrac{T_1}{P_1}\\[/tex]

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf \underline{T_2 = \dfrac{T_1}{P_1}\times P_2}\\[/tex]

(Volume is constant )

Where-

[tex]\sf P_1[/tex] = Initial pressure[tex]\sf P_2[/tex] = Final pressure[tex]\sf T_1[/tex] = Initial temperature[tex]\sf T_2[/tex] = Final temperature

As per question, we are given -

[tex]\sf P_1[/tex] = 893 mmHg[tex]\sf T_1[/tex] = 49.3°C[tex]\sf P_2[/tex] = 778 mmHg

We are given the initial temperature in °C.So, we first have to convert the temperature in Celsius to kelvin by adding 273-

[tex]\sf T_1[/tex] = 49.3+ 273 = 322.3 K

Now that we have obtained all the required values, so we can put them into the formula and solve for T₂:

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf\underline{ T_2 = \dfrac{T_1}{P_1}\times P_2}\\[/tex]

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf T_2 = \dfrac{322.3}{893}\times 778\\[/tex]

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf T_2 = 0.361 \times 778\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf T_2= 280.856...... K\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf T_2= (280.86 - 273)\: °C\\[/tex]

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf \underline{T_2 = 7.8 \:°C}\\[/tex]

Therefore,the new temperature of the gas is 7.8°C.

What volume would 20.0g of CO2 occupy at a temperature of 25c and a pressure of 105kPa

Answers

We can use the ideal gas law to solve this problem:

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.

First, we need to calculate the number of moles of CO2 using its molar mass:

molar mass of CO2 = 12.01 + 2(15.99) = 44.01 g/mol

moles of CO2 = 20.0 g / 44.01 g/mol = 0.454 mol

Next, we can rearrange the ideal gas law to solve for V:

V = (nRT) / P

V = (0.454 mol)(8.31 J/(mol·K))(298 K) / (105 kPa) = 10.5 L

Therefore, 20.0 g of CO2 would occupy a volume of 10.5 L at a temperature of 25°C and a pressure of 105 kPa.

If you wanted to make Kool-Aid ice cubes would you need to be slightly above or slightly below 0c? Why?

Answers

Answer:

To make Kool-Aid ice cubes, you must be slightly below 0°C (32°F) to freeze the liquid into solid ice cubes. The freezing point of water is 0°C (32°F), but adding Kool-Aid powder to water lowers its freezing point. However, the exact freezing point would depend on the Kool-Aid mix's sugar content and other ingredients. In general, the more sugar and other additives in the Kool-Aid mix, the lower the freezing point of the liquid.

How many atoms are in 2 H2SO4?

Answers

Answer:

14

Explanation:

There are 14 atoms in 2H2SO4. Given - Chemical formula. Solution - The atom and number of atoms are - 2*2 Hydrogen + 1*2 Sulphur + 4*2 Oxygen.Aug 11, 2020

g for elements in the periodic table, electronegativity increases from left to right and decreases from top to bottom.bond polarity increases with electronegativity difference between the atoms in the bond.which combination of elements will be most likely to form an ionic compound?

Answers

The combination of elements that will be most likely to form an ionic compound is one where there is a large difference in electronegativity between the two atoms. This is because ionic bonds are formed when there is a transfer of electrons from one atom to another, resulting in the formation of cations and anions.

In general, metal atoms tend to have low electronegativities, while nonmetal atoms tend to have high electronegativities. Therefore, a combination of a metal and a nonmetal is most likely to form an ionic compound.

For example, sodium (Na) is a metal with low electronegativity, while chlorine (Cl) is a non-metal with high electronegativity. When sodium and chlorine react, sodium donates its outer electron to chlorine, forming the ionic compound sodium chloride (NaCl).

Other examples of metal-nonmetal combinations that are likely to form ionic compounds include magnesium (Mg) and oxygen (O) (forming MgO), and aluminium (Al) and fluorine (F) (forming AlF3).

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What is the frequency of green light that has a wavelength of 499 nm?
(c = 3.00 x 108 m/s)

Answers

Answer: ν= [tex]6.01 * 10^{20[/tex] hz

Explanation:

speed of light (c) = wavelength * frequency

[tex]3*10^8 = 499 * 10^{-9} *[/tex] ν

ν= [tex]6.01 * 10^{20[/tex] hz

The speed of light is described as the product of the wavelength and frequency of the light wave. Every color of the spectrum corresponds to a different wavelength and frequency.

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the electronegativity is 2.1 for h and 2.5 for i. based on these electronegativities, hi would be expected to

Answers

Based on the electronegativities of 2.1 for H and 2.5 for I, we can predict that HI (hydrogen iodide) would be expected to be a polar covalent molecule, with the iodine atom having a partial negative charge (δ-) and the hydrogen atom having a partial positive charge (δ+).

This is because electronegativity is the measure of an atom's ability to attract shared electrons in covalent bond. In the HI molecule, the iodine atom has a higher electronegativity than the hydrogen atom, which means it has a greater ability to attract the shared electrons in the covalent bond toward itself.

As a result, the electrons in the HI molecule will be more strongly attracted to the iodine atom, causing the iodine atom to have a partial negative charge and the hydrogen atom to have a partial positive charge.

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a student titrates an unknown weak acid ha to a pale- pink phenolphthalein endpoint with 25.0 ml of 0.100 m naoh. the student then adds 13.0 ml of 0.100 m hcl. the ph of the resulting solution is 4.7. how is the value of pka for the unknown acid related to 4.7?

Answers

The pH of the resulting solution after the addition of 13.0 mL of 0.100 M HCl is 4.7. This indicates that the solution is acidic and that there is still some of the weak acid HA remaining in the solution.

The addition of the strong acid HCl will react with the weak base A- produced during the titration, forming the weak acid HA and neutralizing some of the OH- ions present. This will result in a lower pH than the pH at the equivalence point, and the difference between the two pH values can be used to calculate the dissociation constant (pKa) of the weak acid.

At the equivalence point, the pH is determined by the dissociation constant (Ka) of the weak acid. In this case, the pale-pink phenolphthalein endpoint indicates that the pH at the equivalence point is approximately 8.5-9.5.

Since the pH at the equivalence point is higher than the pH of 4.7 after the addition of HCl, the weak acid must be less dissociated at the latter pH.

This means that the pKa of the weak acid is higher than the pH of 4.7, because a higher pKa corresponds to a weaker acid and a lower degree of dissociation.

Therefore, we can conclude that the pKa of the unknown weak acid HA is greater than 4.7, based on the pH of the resulting solution after the addition of HCl.

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What change occurs when a liquid evaporates?

A The particles absorb heat and get closer together.
B The particles absorb heat and spread farther apart.
C The particles release heat and spread farther apart.
D The particles release heat and get closer together.

Answers

The correct answer is B) The particles absorb heat and spread farther apart.

When a liquid evaporates, the particles at the surface of the liquid gain enough energy (usually in the form of heat) to overcome the attractive forces between them and escape into the air as a gas. This energy breaks the intermolecular bonds between the liquid particles and allows them to move more freely.

The absorption of heat causes an increase in the kinetic energy of the particles, which makes them move faster and collide with each other more frequently. These collisions help to break the intermolecular bonds between the liquid particles.

As more and more particles escape from the surface of the liquid, the concentration of the liquid decreases, and eventually, the liquid can completely evaporate into a gas. The escaped particles also carry away some of the energy from the liquid, which is why the evaporation process cools down the remaining liquid and its surroundings.

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what will be the ph of a buffer solution containing an acid of pka8.1, with an acid concentration equivalent to that of its conjugate base?

Answers

The pH of the buffer solution will be 8.1. containing an acid of pka8.1, with an acid concentration equivalent to that of its conjugate base

The pH of a buffer solution can be determined using the Henderson-Hasselbalch equation, which is:

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

In this case, the buffer solution contains an acid with a pKa of 8.1 and has an acid concentration ([HA]) equal to the concentration of its conjugate base ([A-]). Therefore, the ratio [A-]/[HA] is equal to 1.

Now, let's plug in the values into the equation:

pH = 8.1 + log(1)

Since the log of 1 is 0, the equation simplifies to

pH = 8.1

So the pH of the buffer solution will be 8.1. This is because the acid and its conjugate base are present in equal concentrations, maintaining a balanced pH close to the pKa value of the acid. The buffer's ability to resist changes in pH comes from the presence of both the weak acid and its conjugate base, which can neutralize any added acids or bases and keep the pH stable.

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what will happen if 50.00 ml of 2.0x10-4 m pb(no3)2 is mixed with 50.00 ml of 2.0x10-4 m nh4f? ksp for pbbr2 is 4.0x10-5

Answers

Since Q < Ksp (4.0x10-5), PbF2 will not precipitate out of solution. The solution will contain Pb2+, F-, NH4+, and NO3- ions in equilibrium.

When lead nitrate (Pb(NO3)2) and ammonium fluoride (NH4F) are mixed, they will react to form lead fluoride (PbF2) and ammonium nitrate (NH4NO3) according to the following balanced chemical equation:

Pb(NO3)2 + 2 NH4F → PbF2 + 2 NH4NO3

To determine whether or not PbF2 will precipitate out of solution, we need to calculate the ion product (Q) and compare it to the solubility product constant (Ksp) for PbF2. The ion product is calculated by multiplying the concentrations of the lead ion (Pb2+) and the fluoride ion (F-) in solution.

First, we need to calculate the concentration of Pb2+ and F- in solution after the reaction has occurred. Since the initial concentrations of Pb(NO3)2 and NH4F are both 2.0x10-4 M, the total volume of the solution is 100.00 mL. Therefore, the concentration of Pb2+ and F- after the reaction will be:

[Pb2+] = (50.00 mL / 100.00 mL) × 2.0x10-4 M = 1.0x10-4 M

[F-] = (50.00 mL / 100.00 mL) × 2.0x10-4 M = 1.0x10-4 M

Now we can calculate the ion product:

Q = [Pb2+][F-] = (1.0x10-4 M)(1.0x10-4 M) = 1.0x10-8

Since Q < Ksp (4.0x10-5), PbF2 will not precipitate out of solution. The solution will contain Pb2+, F-, NH4+, and NO3- ions in equilibrium.

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At the end of the show, Bill Nye says, "If you'll excuse me, I've got some___________percolation range to compute.​

Answers

Answer: Soil

Explanation:

100.0ml solution of 0.30m cu(no3)2 is mixed with 100.0ml of 6.0 m ammonia solution what is cu in the resulting mixture

Answers

100.0ml solution of 0.30m cu(no3)2 is mixed with 100.0ml of 6.0 m ammonia solution, the concentration cu in the resulting mixture is: 0.15 M.

To find the concentration of Cu in the resulting mixture, follow these steps:

1. Calculate the moles of Cu(NO3)2 in the initial solution: moles = Molarity × Volume
  moles of Cu(NO3)2 = 0.30 M × 0.100 L = 0.030 mol

2. Determine the moles of Cu in the Cu(NO3)2 solution (1:1 ratio between Cu and Cu(NO3)2)
  moles of Cu = 0.030 mol

3. Calculate the total volume of the resulting mixture:
  Total volume = Volume of Cu(NO3)2 solution + Volume of ammonia solution
  Total volume = 0.100 L + 0.100 L = 0.200 L

4. Calculate the new concentration of Cu in the resulting mixture: Molarity = moles / Volume
  Molarity of Cu = 0.030 mol / 0.200 L = 0.15 M

So, the concentration of Cu in the resulting mixture is 0.15 M.

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Which of the following is most likely to produce a loud echo? Explain your answer. (Use science terminology)

A) talking in a furnished, carpeted room

B) singing in a tiled shower

C) yelling across an open field

Answers

[tex] \: [/tex]

Option B, singing in a tiled shower, is most likely to produce a loud echo. This is because sound waves reflect more easily off hard and smooth surfaces, which are found in a tiled shower. This means that sound waves will bounce back and forth between the walls, floor, and ceiling of the shower, creating a series of reflections that can produce a perceptible echo. In comparison, a furnished, carpeted room (option A) would have more sound-absorbing materials, such as furniture and carpet, which would dampen the sound waves and reduce the likelihood of an echo. Option C, yelling across an open field, would also not produce a loud echo, as it requires a reflective surface to bounce off of. In an open field, there are no nearby surfaces for the sound waves to reflect off of, so they will simply dissipate into the air.

a 5.00 ml sample of vinegar contains 0.2568 g of acetic acid. if the density of vinegar is 1.00 g/ml, calculate the % acetic acid by mass. your answer: question 3 options: answer

Answers

The % acetic acid by mass in the vinegar sample is 5.14%.

The first step is to calculate the mass of the vinegar sample using its density:

Mass of vinegar = Volume of vinegar x Density of vinegar

Mass of vinegar = 5.00 ml x 1.00 g/ml = 5.00 g

Next, we can use the mass of acetic acid in the sample to calculate the percentage of acetic acid by mass:

% Acetic Acid = (Mass of acetic acid / Mass of vinegar) x 100%

% Acetic Acid = (0.2568 g / 5.00 g) x 100%

% Acetic Acid = 5.14%

To solve the problem, we first need to know the mass of the vinegar sample. We are given its volume and density, so we can use the density formula (density = mass / volume) to calculate the mass. Once we have the mass of the vinegar, we can use the mass of acetic acid in the sample (also given) to calculate the percentage of acetic acid by mass using the formula % Acetic Acid = (Mass of acetic acid / Mass of vinegar) x 100%.

This formula calculates the proportion of the mass of the sample that is due to acetic acid. Finally, we multiply the result by 100% to express the answer as a percentage. Therefore, the percentage of acetic acid by mass is 5.14%.

The complete question is

A 5.00 ml sample of vinegar contains 0.2568 g of acetic acid. if the density of vinegar is 1.00 g/ml, calculate the % acetic acid by mass.

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oxymercuration-demercuration of 2-methyl-2-butene affords which product? select answer from the options below 3-methyl-1-butanol 3-methyl-2-butanol 2-methyl-2-butanol mercuric acetate

Answers

oxymercuration-demercuration of 2-methyl-2-butene gives the product 2-methyl-2-butanol.

Oxymercuration-demercuration is the process involving electrophilic activation of an alkene by a mercuric acetate group. It is followed by the  addition of water firstly and secondly, reductive demercuration by sodium borohydride.

In the first step, an electrophilic HgOAc+ ion is added to the double bond which gives a mercurinium ion .

In the second step, the species reacts with a nucleophilic water molecule. Due to this nucleophilic attack, there forms a bonding of an HgOAc group and a OH group on the adjacent carbon atoms.

The final product involves Markovnikov addition reaction where the OH group is bonded to the more substituted carbon atom of the alkene.

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which acid and base react to form water and sodium sulfate? * (1) sulfuric acid and sodium hydroxide (2) sulfuric acid and potassium hydroxide (3) sulfurous acid and sodium hydroxide (4) sulfurous acid and potassium hydroxide

Answers

The reaction between Sulfuric Acid and Sodium Hydroxide forms Water and Sodium Sulphate. Therefore option (1) is the correct answer.

Neutralisation is a chemical reaction where an acid and a base react with each other quantitatively. It is also written as Neutralisation. The acid strength of the reactant gives the pH of the neutralised solution.

Ever experienced a burning sensation in your stomach after eating too much spicy food? This is due to the formation of acid in the stomach. This problem can be cured by the consumption of an antacid which neutralizes the effect of acid, and this reaction is called a neutralisation reaction.

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0.155 moles of c is reacted with 0.117 moles of o2 to form co and co2. $$ using the balanced chemical equation, calculate the moles of co2 which could be produced based upon the moles of the each reagent. based on the theoretical production of co2 which reagent, if either, is the limiting reagent for this problem?

Answers

The balanced chemical equation for the reaction between carbon (C) and oxygen (O2) to form carbon monoxide (CO) and carbon dioxide (CO2) is below and the moles of CO2 produced is 0.117.

C + O2 → CO + CO2

According to the equation, for every 1 mole of C, we need 1 mole of O2 to produce 1 mole of CO and 1 mole of CO2.

Given that we have 0.155 moles of C and 0.117 moles of O2, we can use the mole ratio from the balanced equation to determine how many moles of CO2 could be produced:

Moles of CO2 = Moles of C = 0.155 moles

Therefore, based on the moles of each reagent, we could produce a maximum of 0.155 moles of CO2.

To determine the limiting reagent, we need to calculate the amount of CO2 that would be produced if all of the limiting reagent were consumed. We can do this by comparing the amount of CO2 that would be produced by each reagent and identifying the one that produces the smaller amount:

Using C as the limiting reagent:

Moles of CO2 produced = Moles of C = 0.155 moles

Using O2 as the limiting reagent:

Moles of CO2 produced = Moles of O2 × (1 mole CO2 / 1 mole O2) = 0.117 moles × (1 mole CO2 / 1 mole O2) = 0.117 moles

Since the amount of CO2 produced by the reaction with C is greater than the amount produced by the reaction with O2, we can conclude that O2 is the limiting reagent for this problem. Therefore, only 0.117 moles of CO2 could be produced based on the available amount of O2, and any excess C would be left over after the reaction.

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clerice midter
The diagram below is the Bohr model of an atom.
Which best describes this atom?
OA. It has 6 electrons.
OB. It has a positive charge.
O c. It has 6 valence electrons.
OD.
has a full outermost energy level.

Answers

The correct option is (A) - This Bohr Model of atom describes that there are a total of 6 electrons in the given figure.

What is Bohr Model of atom?

The electrons are positioned in circular orbitals at particular distances from the central nucleus in the Bohr model of the atom. These orbits create electron shells or energy levels, which allow us to see how many electrons are present in each shell. The number and the letter "n" are used to identify these energy levels. The first energy level nearest to the nucleus, for instance, is represented by the 1n shell. Normally, an electron resides in the shell with the lowest energy, which is the one closest to the nucleus. A photon of light's energy can raise it to a higher energy shell, but this is an unstable position, and the electron quickly returns to the ground state.

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Find the mass in grams of 3.10 × 10^23 molecules of F2

Answers

Answer:

19.56160744 g F2 = 19.6 grams F2

Explanation:

Molar mass of F2: 2(19.00)=38.00 g/mol

Atoms --avogadro's number--> moles --molar mass--> grams

in what volume ratio should you mix 1.0 m solutions of nh4cl and nh3 to produce a buffer solution having ph

Answers

To determine the volume ratio of NH4Cl and NH3 solutions required to make a buffer of a specific pH, we need to use the Henderson-Hasselbalch equation:

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

where:

pH = the desired pH of the buffer

pKa = the dissociation constant of the weak acid component of the buffer

[A-] = the concentration of the conjugate base (NH3) of the weak acid in the buffer

[HA] = the concentration of the weak acid component (NH4Cl) in the buffer

The pKa of NH4Cl is 9.25, so we can use this value in the Henderson-Hasselbalch equation. Let's assume that we want to make a buffer with a pH of 9.0.

At the pH of 9.0, we can calculate the ratio of [A-]/[HA] using the following equation:

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

[A-]/[HA] = 10^(9.0 - 9.25) = 0.562

Therefore, we need to mix the NH4Cl and NH3 solutions in a ratio of 0.562:1 to make a buffer with a pH of 9.0. This means that for every 0.562 units of NH3, we need 1 unit of NH4Cl to make the buffer.

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1 m 1 m 1 m Cube Square cube has volume Fach face of the cube has area. The square Im
what is the area of each face of the cube?​

Answers

Each face of the cube has an identical area, which is the same as a square whose side length is equal to the cube's edge length.

The cube's area on each face is given by its 1 meter-long edges as follows:

The cube's face area is equal to the product of its edge length and a square of one meter.

As a result, the cube's faces each have an area of 1 square meter.

What is the size of a cube's faces, individually?

Squaring the side's length yields the area of each face. To get the cube's total surface area, multiply the area of each face by the number of faces.

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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?

Answers

To determine the actual pH of a solution with an unknown pH, a good choice of indicator would be a universal indicator.

A universal indicator is a mixture of several different pH-sensitive dyes that change color over a wide pH range, typically from 1 to 14.

This allows for more precise pH determination than single indicators, which are usually limited to a smaller pH range. Here are the steps to use a universal indicator:

1. Obtain a small sample of the unknown solution.

2. Add a few drops of the universal indicator to the solution.

3. Observe the color change in the solution.

4. Compare the color with the provided pH color chart that comes with the universal indicator.

5. Determine the pH value of the solution based on the color observed. Using a universal indicator will allow you to accurately determine the actual pH of the unknown solution.

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a metal crystallizes with a face-centered cubic lattice. the edge of the unit cell is 434 pm. what is the diameter of the metal atom?

Answers

In a face-centered cubic (FCC) lattice, each unit cell contains atoms at each of its eight corners and one atom at the center of each of its six faces.

To calculate the diameter of the metal atom, we need to know the relationship between the edge length of the unit cell and the diameter of the atom. In an FCC lattice, the atoms are arranged in a close-packed arrangement, where the atoms touch along the face diagonal of the unit cell.

The face diagonal of an FCC unit cell can be calculated using the Pythagorean theorem:

face diagonal = sqrt(2) x edge length

Substituting the given value for the edge length of the unit cell:

face diagonal = sqrt(2) x 434 pm = 614 pm

The diameter of the metal atom is equal to the distance between the centers of two adjacent atoms along the face diagonal of the unit cell. In an FCC lattice, the atoms touch along the face diagonal, so the distance between the centers of two adjacent atoms is equal to the length of the face diagonal minus the diameter of the atom:

diameter of atom = face diagonal - atomic radius

where atomic radius is half of the diameter of the atom.

Rearranging this equation to solve for the diameter of the atom, we get:

diameter of atom = face diagonal - 2 x atomic radius

Substituting the given value for the face diagonal and solving for the atomic radius:

atomic radius = (face diagonal - diameter of atom)/2

diameter of atom = face diagonal - 2 x atomic radius

diameter of atom = 614 pm - 2 x atomic radius

We are given the edge length of the unit cell, but we need to find the diameter of the atom. Therefore, we need to rearrange the above equations to solve for the diameter of the atom:

atomic radius = edge length/2

diameter of atom = face diagonal - 2 x atomic radius

diameter of atom = 614 pm - 2 x (edge length/2)

diameter of atom = 614 pm - 2 x 434 pm

diameter of atom = 614 pm - 868 pm

diameter of atom = -254 pm (This answer is negative, which is not physically meaningful.)

Therefore, we cannot calculate the diameter of the metal atom with the given information. There might be some mistake in the calculation or the given value for the edge length of the unit cell.

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A camper walked from point A to point B taking the path shown by the dotted line. What is the approximate distance the camper walked? a. 2.0 miles downhill b. 30 miles downhill c. 2.0 miles uphill d. 30 miles uphill

Answers

a. 2.0 miles downhill

This is because the path taken by the camper appears to go primarily downhill and is relatively short in distance. However, the actual distance may be more or less than 2.0 miles depending on the scale of the diagram.

How many calories of heat were added to 449.1 g of water to raise its temperature from 25 degrees C to 55 degrees C? (standard notation)

Answers

13473 calories of heat were added to 449.1 g of water to raise its temperature from 25 degrees C to 55 degrees C.

To calculate the heat added to water, we can use the following formula:

Q = m * c * ΔT

Q = heat added (in calories)

m = mass of water (in grams)

c = specific heat of water (1 calorie/gram degree Celsius)

ΔT = change in temperature (in degrees Celsius)

Using the given values:

m = 449.1 g

ΔT = (55 - 25) = 30 degrees C

Substituting these values into the formula, we get:

Q = 449.1 g * 1 cal/g °C * 30°C

Q = 13473 calories

Calories are a unit of measurement for energy. They are used to quantify the amount of energy in food and the amount of energy that our bodies burn through physical activity. One calorie is defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius

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A. given that the fermi energy for cu is 7.0 ev at absolute zero, calculate the ef at 300 k. what is the percentage change in ef and what is your conclusion?b. given the fermi energy for cu at absolute zero, calculate the average energy and mean speed per conduction electron at absolute zero and 300 k, and comment.

Answers

Answer:

Explanatidescribe everyday events such as shaving, ear peircing, and brushing teeth so that they do not sound like "primitive" customs.

on:

arrange the following elements in order of increasing metallic character: fr, sn, in, ba, se. note: 1 = most ; 6 = least ba 2 se 5 fr 1 in

Answers

The correct order is: Fr 1, Ba 2, In 3, Sn 4, Se 5

To arrange the following elements in order of increasing metallic character (1 = most, 6 = least): Fr, Sn, In, Ba, Se, you should consider their positions in the periodic table. As you move down a group, metallic character increases; as you move left across a period, metallic character also increases.

Step 1: Locate the elements in the periodic table:
Fr (Francium): Group 1, Period 7
Sn (Tin): Group 14, Period 5
In (Indium): Group 13, Period 5
Ba (Barium): Group 2, Period 6
Se (Selenium): Group 16, Period 4

Step 2: Order the elements according to the trends in metallic character:
1. Fr (most metallic character)
2. Ba
3. In
4. Sn
5. Se (least metallic character)

So the correct order is: Fr 1, Ba 2, In 3, Sn 4, Se 5.

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