Which reactions have a positive ΔSrxn? 2A(g)+B(g)⟶4C(g) 2A(g)+3B(g)⟶4C(g) A(s)+2B(g)⟶C(g) 2A(g)+B(s)⟶3C(g)

Answers

Answer 1

Answer:

Most likely:

[tex]{\rm 2\, A}\, (g) + {\rm B}\, (g) \to 4\, {\rm C}\, (g)[/tex] (the first choice.)

[tex]2\, {\rm A}\, (g) + {\rm B}\, (s) \to 3\, {\rm C}\, (g)[/tex] (the fourth choice.)

Explanation:

[tex]\Delta S_\text{rxn}[/tex] denotes the entropy change in a reaction.

The value of [tex]\Delta S_\text{rxn}[/tex] is greater than zero if the reaction corresponds to an increase in entropy. In other words, entropy should be higher for the products of this reaction than for its reactants.

The exact entropy of each species depends on both the environment (temperature, pressure, etc.) and on the structure of the species. However, there are some general trends.

Consider one mole of some gaseous molecules and one mole of some solid particles. If that gas and that solid are under the same temperature and pressure, which one would have a higher entropy? Generally, the gas would have a higher entropy.

Also, the entropy of a gas is approximately proportional to the number of particles in that gas.

Therefore, it is likely that [tex]\Delta S_\text{rxn}[/tex] would be positive for a reaction if there are more gas particles among the products than among the reactants.

Note that [tex](s)[/tex] is the state symbol for solids, whereas [tex](g)[/tex] is the state symbol for gases.

In this question:

First reaction: [tex]{\rm 2\, A}\, (g) + {\rm B}\, (g) \to 4\, {\rm C}\, (g)[/tex].

In each unit of this reaction, there are:

two gas particles among the reactants.four gas particles among the products. The number of gas particles that this reaction produces is larger than the number of gas particles that it consumes. Therefore, it is likely that [tex]\Delta S_\text{rxn} > 0[/tex] for this reaction.

Second reaction: [tex]{\rm 2\, A}\, (g) + 3\, {\rm B}\, (g) \to 4\, {\rm C}\, (g)[/tex].

In each reaction, there are:

five gas particles among the reactants.four gas particles among the products. The number of gas particles that this reaction produces is smaller than the number of gas particles that it consumes. Therefore, it is likely that [tex]\Delta S_\text{rxn} < 0[/tex] for this reaction.

Third reaction: [tex]{\rm A}\, (s) + 2\, {\rm B}\, (g) \to {\rm C}\, (g)[/tex].

In each reaction, there are:

two gas particles among the reactants.one gas particle among the products. The number of gas particles that this reaction produces is smaller than the number of gas particles that it consumes. Therefore, it is likely that [tex]\Delta S_\text{rxn} < 0[/tex] for this reaction.

Fourth reaction: [tex]{\rm 2\, A}\, (g) + {\rm B}\, (s) \to 3\, {\rm C}\, (g)[/tex].

In each unit of this reaction, there are:

two gas particles among the reactants (note that the state symbol [tex](s)[/tex] suggests that [tex]{\rm B}\, (s)[/tex] is not a gas.)three gas particles among the products. The number of gas particles that this reaction produces is larger than the number of gas particles that it consumes. Therefore, it is likely that [tex]\Delta S_\text{rxn} > 0[/tex] for this reaction.

Related Questions

An atom has 10 protons and 10 electrons. What happens to the charge if you add 1 more electron

Answers

Answer:

it becomes a negstive charge

A student with a body temperature of 37℃ holds a piece of ice that has a temperature of -8℃. Which statement best explains what happens?

A. Heat transfers coldness from the ice to the student's hand.
B. Thermal energy transfers heat from the student's hand to the ice.
C. Heat transfers thermal energy from the student's hand to the ice.
D. Thermal energy transfers coldness from the student's hand to the ice.

Answers

Answer: C. Heat transfers thermal energy from the student's hand to the ice.

Explanation:  It seems confusing; b and c seem to be saying the same thing, but the definition of heat is the transfer of thermal energy from a warmer object to a colder object.

How many alkyl substituents does N-ethyl-N-methylaniline have?
one
two
O three
o eight
none

Answers

Answer:

Two.

Explanation:

Hello!

In this case, considering the attached picture wherein you can see the presence of the parent chain as aniline, we can see radicals at the nitrogen, named by N-ethyl and N-methyl which are the present alkyl substituents. In such a way, the benzene ring is not considered an alkyl radical because it belongs to the parent chain on aniline and therefore, N-ethyl-N-methylaniline has two alkyl substituents.

Best regards!

There are two alkyl substituents attached to the nitrogen; one ethyl and one methyl group

Aniline consists of a benzene ring to which an -NH2 moiety is attached. Usually, it is possible for the any of the two hydrogen atoms in the -NH2 moiety to become substituted leading to N-alkylated product.

In the compound N-ethyl-N-methylaniline, there are two alkyl substituents attached to the nitrogen; one ethyl and one methyl group as shown in the image attached to this answer.

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Please help me it’s due today at 6:00pm please help me please please

Answers

Answer:

a) an opposing force act on it

i hope its true

If an ideal gas has a pressure of 5.87 atm,
a temperature of 26.86 ∘C,
and a volume of 77.31 L,
how many moles of gas are in the sample?

Answers

Answer:

5.87/26.86=77.31/...

Explanation:

after solving this u can find the answer in easy way

Compounds of copper(II) are generally colored, but compounds of copper(I) are usually colorless. Use crystal field theory to explain why this is true.

Answers

Answer:

See explanation

Explanation:

The crystal field theory assumes the interaction between the central metal ion and ligands to be purely electrostatic.

The five d orbitals remain degenerate until they are surrounded by ligands which split the degeneracy of the d orbitals depending on the crystal fields formed to give either square planar, octahedral, tetrahedral or other kinds of crystal fields.

The electronic configuration of Cu II ion is 1s2 2s2 2p6 3s2 3p6 3d9. Its colour arises from an incomplete d orbital which makes d - d electron transition possible.

On the other hand, the electron configuration of copper I is  1s2 2s2 2p6 3s2 3p6 3d10. We can see that the d orbital is completely filled. Hence copper I ion has no color due to its completely filled d- orbitals

A gas-forming reaction produces 1.95 m3 of gas against a constant pressure of 196.0 kPa. Calculate the work done by the gas in joules.

Answers

Answer:

Work done W = -382,206 J (Approx)

Explanation:

We know that;

1 atm = 101.32 kPa

1 L-atm = 101.325 J

1 m³ = 1,000 L

Computation:

Work done W = -P∆V

Pressure = 196 kPa × (1 / 101.32 kPa)

Pressure = 1.9344 atm

∆V = 1.95 × (1000 L) = 1,950 L

So,

W = -(1.9344 atm) × (1,950 L)

W = -3772.0 L-atm

Work done W = -3772.0 L-atm × (101.325 J / 1 L.atm)

Work done W = -382,206 J (Approx)

The work done by the gas in Joules is equal to 3,763.5‬ Joules.

Given the following data:

Pressure = 196.0 kPa. Volume = 1.95 [tex]m^3[/tex]

Conversion:

1 atm = 101.325

X atm = 196.0 kPa

X = [tex]\frac{196.0}{101.325} = 1.93\; atm[/tex]

Conversion:

1 [tex]m^3[/tex] = 1000 Liter

1.95 [tex]m^3[/tex] = 1950 Liter

To calculate the work done by the gas in Joules:

Mathematically, the work energy by a system is given by the formula:

[tex]Work = P \delta V[/tex]

Where:

P is the pressure. V is the volume.

Substituting the parameters into the formula, we have

[tex]Work\;energy = 1.93 \times 1950[/tex]

Work energy = 3,763.5‬ Joules.

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Which element has a smaller atomic radius?
tungsten (74) or oxygen (8)

Answers

Answer:

Oxygen

Explanation:

Atomic radius trend

-decreases from left to right

-increases from top to bottom

Tungsten is in period 7, which has a larger atomic radius

Oxygen is in period 2, which is in a lower energy level and is on the right side. Therefore, has a smaller atomic radius.

The heat of vaporization of acetic acid is . Calculate the change in entropy when of acetic acid condenses at .

Answers

The question is incomplete, the complete question is;

The heat of vaporization ΔHv of acetic acid HCH3CO2 is 41.0 /kJmol. Calculate the change in entropy ΔS when 954.g of acetic acid condenses at 118.1°C. Be sure your answer contains a unit symbol. Round your answer to 3 significant digits.

Answer:

-1.67 JK-1

Explanation:

Since Heat of vaporization of acetic acid = 41.0 kJ/mol

Therefore:

Heat of condensation of acetic acid = -41.0 kJ/mol

Mass of acetic acid = 954 g

Temperature of condensation = 118.1 °C or 391.1 K

Number of moles of acetic acid = 954 g/60g/mol = 15.9 moles

Heat evolved during condensation = 15.9 moles *  -41.0 kJ/mol = -651.9 KJ

Entropy change (ΔS) = Heat evolved/ Temperature = -651.9 KJ/391.1 K

Entropy change (ΔS) = -1.67 JK-1

What's is the definition of an atom

Answers

Atom, smallest unit into which matter can be divided without the release of electrically charged particles. It also is the smallest unit of matter that has the characteristic properties of a chemical element. As such, the atom is the basic building block of chemistry.

The tiny particles called atoms are the basic building blocks of all matter. Atoms can be combined with other atoms to form molecules, but they cannot be divided into smaller parts by ordinary means.

HELP ME PLEASE I will mark brainliest

Answers

Answer:

Nice pic there

Explanation:

No need

A chemist dissolves 249.mg of pure perchloric acid in enough water to make up 380.mL of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.

Answers

Answer:

pH = 2.18

Explanation:

Perchloric acid (HClO₄) is a strong acid. This means that in an aqueous solution it completely dissociates into H⁺ and ClO₄⁻ species.

First we convert 249 mg HClO₄ into moles, using its molecular weight:

249 mg HClO₄ ÷ 100.46 mg/mmol = 2.49 mmol HClO₄

Because it is a strong acid, 2.49 mmol HClO₄ = 2.49 mmol H⁺

We calculate the molar concentration of H⁺:

2.49 mmol H⁺ / 380 mL = 6.52x10⁻³ M

Finally we calculate the pH of the solution:

pH = -log[H⁺] = -log(6.52x10⁻³)pH = 2.18

Each pure substance has characteristic physical and chemical properties that can be used to identify it.

Compare and contrast physical properties and chemical properties of a substance. Give and example for each:

Answers

Stuff like color, and density are examples of physical properties. Flammability and corrosion/oxidation are examples of chemical properties

Calculate the standard cell potential, ∘cell, for the equation Co(s)+F2(g)⟶Co2+(aq)+2F−(aq) Use the table of standard reduction potentials. ∘cell=

Answers

Answer:

3.15 V

Explanation:

Step 1: Write the balanced cell reaction

Co(s) + F₂(g) ⟶ Co²⁺(aq) + 2 F⁻(aq)

Step 2: Identify both half-reactions:

Cathode (reduction): F₂(g) + 2 e⁻ ⟶ 2 F⁻(aq)    E°red = 2.87 V

Anode (oxidation): Co(s) ⟶ Co²⁺(aq) + 2 e⁻      E°red = -0.28 V

Step 2: Calculate the standard cell potential

We will use the following expression.

E°cell = E°red,cathode - E°red,anode

E°cell = 2.87 V - (-0.28 V) = 3.15 V

Given E°cell > 0, the reaction is spontaneous.

Taking into account the definition of standard cell potential, E°cell has a value of 3.15 V.

The balanced cell reaction is:

Co(s) + F₂(g) ⟶ Co²⁺(aq) + 2 F⁻(aq)

First of all, it must be taken into account that oxidation is a reaction where an atom, ion or molecule loses electrons while reduction corresponds to the gain of electrons from an atom, ion or molecule.

Both oxidation and reduction depend on the change in the oxidation state of the atom, that is, on the difference in the charge of the atom in a reaction.

The oxidation and reduction reactions always occur simultaneously for what are generally known as oxidation-reduction reactions or redox reactions.

So, the anode corresponds to the negative electrode which normally oxidizes in the electrolytic chemical reaction while the cathode corresponds to the positive electrode which normally reduces its oxidation state when it receives electrons.

Si, in this case, the both half-reactions will be:

Cathode (reduction): F₂(g) + 2 e⁻ ⟶ 2 F⁻(aq)    E°red = 2.87 V Anode (oxidation): Co(s) ⟶ Co²⁺(aq) + 2 e⁻      E°red = -0.28 V

The potential of an Ecel cell is a measure of the difference in electronic energy between the two electrodes. The electronic energy of each electrode is related to the force with which the reaction occurs at the electrode-solution interface. The unit in which it is measured is the volt.

In electrochemistry, because a cell reaction is made up of two half-cell reactions, each of which has a characteristic electrode potential, the potentials measure the driving force of the two half-reactions.

The cell potential is obtained by subtracting the potentials of both half cells as shown below:

E°cell= Ecatode - Eanode

So, in this case, the Ecell is calculated as:

E°cell = 2.87 V - (-0.28 V) = 3.15 V

In summary, E°cell has a value of 3.15 V.

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A party balloon filled with helium deflates to 2/3 of its original volume in 8.0 hours. How long will it take an identical balloon filled with the same number of moles of air (ℳ = 28.2 g/mol) to deflate to 1/2 of its original volume?

Answers

Answer:

The easy way to do this is to assume the number of moles. Make it a number easily divided by both 2 and 3, so say 6. Now you can have numbers to plug in to Graham's Law to find the second rate, then use the second rate to find the time. Does that make sense?

To prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol), how many grams of sodium chloride is required?

Answers

This answer did not come from me but here you go!
44 g NaCl
Explanation:
The problem provides you with the molarity and volume of the target solution, so your first step here will be to use this information to figure out how many moles of sodium chloride,
NaCl
, it must contain.
Once you know that, use the compound's molar mass to convert the number of moles to grams.
So, molarity is defined as the number of moles of solute per liter of solution. In your case, a
0.77 M
solution will contain
0.77
moles of sodium chloride, your solute, in
1.0 L
of solution.
Your target solution has a volume of
985
mL

1 L
10
3
mL
=
0.985 L
which means that it will contain
0.985
L solution

= 0.77 M

0.77 moles NaCl
1
L solution
=
0.75845 moles NaCl
Sodium chloride has a molar mass of
58.44 g mol

1
, which basically means that one mole of sodium chloride has a mass of
58.44 g
.
In your case,
0.75845
moles of sodium chloride will have a mass of
0.75845
moles NaCl

58.44 g
1
mole NaCl
=




¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
a
a
44 g
a
a

11.12 grams of sodium chloride is required to prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol).

HOW TO CALCULATE MASS:

The mass of a substance can be calculated by multiplying the number of moles of the substance by its molar mass.

However, the number of moles of sodium chloride must first be calculated by multiplying the molarity by its volume.

Molarity = no. of moles ÷ volume

0.500M = n ÷ 0.380L

n = 0.5 × 0.380

n = 0.19mol

mass of NaCl = 58.5g/mol × 0.19mol

Mass of NaCl = 11.12g

Therefore, 11.12 grams of sodium chloride is required to prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol).

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Question 2 (2 points)
Saved
How many grams of water do will you need to prepare 480 g of 8.5% solution of
C6H12O6

Answers

Answer:

[tex]m_w=439.2g[/tex]

Explanation:

Hello!

In this case, since the by-mass percent of a solution is a measure of the mass of the solute over the mass of the solution:

[tex]\%m/m=\frac{m_{solute}}{m_{solution}} *100\%[/tex]

As we know the mass of the solution and the by-mass percent, we can compute the mass of glucose in the 480 g of solution:

[tex]m_{solute}=\frac{\%m/m*m_{solution}}{100\%}[/tex]

Thus, by plugging in the data, we obtain:

[tex]m_{solute}=\frac{8.5\%*480g}{100\%}=40.8g[/tex]

Finally, since the solution is made up of glucose and water, we compute the mass of water as follows:

[tex]m_w=m_{sol}-m_{solute}=480g-40.8g\\\\m_w=439.2g[/tex]

Best regards!

What property of gases confirms that the space between the particles of gas is significantly larger than when the same substance is in a liquid state?
A. Mobility
B. Reactivity
C. Volatility
D. Compressibility​

Answers

The answer is D. Compressibility

Answer:

D. Compressibility​

Explanation:

Give the name for the molecular compound O3Cl2.​

Answers

Answer:

dichlorine trioxide

Explanation:

di-2 tri-3 there are three oxygens and two chlorines.

Answer:

Dichlorine Trioxide

Explanation:

The molar mass and molecular weight of Cl2O3 is 118.904.

A substance that functions to prevent rapid, drastic changes in the pH of a body fluid by changing strong acids and bases into weak acids and bases is called a(n):

A. Buffer
B. Salt
C. Enzymes
D. Coenzyme

Answers

I believe the answer is A) Buffer
A. Buffer is the answer.

The movement of water is able to transport minerals and nutrients. Which statement best explains why water is able to do this?
A. Water has a density of one gram per milliliter
B. Water is an excellent solvent
C. Water absorbs heat energy
D. Water is a liquid at room temperature​

Answers

The correct answer would be B

among the intermolecular forces,which forces are typically the weakest

Answers

Answer:

The London dispersion force is the weakest intermolecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles.

Give two everyday examples of the thermal energy of a substance being decreased

Answers

Answer:

An example of the thermal energy of a substance being decreased is with our food. With the thermal energy of food being decreased it is easier for foods to be eaten comfortably without any damage to the tongue or alimentary canal.

Another good example is in the handling of hot objects in the home. Thermal energy decrease in objects such as iron, pots etc helps to prevent serious burns and injuries.

Answer:

Water turning into ice

juice frozen to make popsicles

Explanation:

When something goes from liquid to a solid, that is a process called freezing. When a object loses thermal energy the particles move slower forming a solid.

What is the molarity of 9.0 moles of NaCl dissolved in 15.0 liters if solution?

Answers

Molarity= moles/Volume => 9/15 = 0.6 mol/L

For Hydrogen bonding H atom needs to be bonded to which other atoms?

Answers

Answer:

Hydrogen bonding occurs when a hydrogen atom is covalently bonded to N, O, or F atom.

A 2.4L balloon filled with helium at room temperature 25oC is put into liquid nitrogen
(-196oC). What will the new volume be?

Answers

Answer:

V₂ = 0.62 L

Explanation:

Given data:

Initial volume = 2.4 L

Initial temperature = 25°C

Final temperature = -196°C

Final volume = ?

Solution:

Initial temperature = 25°C (25+273 = 298 K)

Final temperature = -196°C ( -196+273 = 77 K)

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume  

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

V₂ = V₁T₂/T₁  

V₂ = 2.4 L × 77 K / 298 k

V₂ = 184.8 L.K / 298 K

V₂ = 0.62 L

How many moles of dinitrogen monoxide are present in 9.3 x 10^22 molecules of this compound?

Answers

Answer:

0.15 moles

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities.

From the question we have

[tex]n = \frac{9.3 \times {10}^{22} }{6.02 \times {10}^{23} } \\ = 0.154485...[/tex]

We have the final answer as

0.15 moles

Hope this helps you

2. Calculate the new molanty of a solution formed when 20 ml of water is added to 100 ml of
0.2M NaOH​

Answers

Answer:

New molarity = M₂ = 0.167 M

Explanation:

Given data:

New molarity = M₂ = ?

Final volume = V₂ = 100mL + 20 mL = 120 mL

Initial volume =M₁ =  100 mL

Initial molarity =V₁ = 0.2 M

Solution:

M₁V₁       =    M₂V₂

0.2 M × 100 mL = M₂ × 100 mL

M₂ = 0.2 M × 100 mL/120 mL

M₂ = 20 M.mL/120 mL

M₂ = 0.167 M

Sean plated an unknown metal onto his silver earring which initially weighed 1.41 g. He constructs an electrolytic cell using his ring as one of the electrodes. After running the cell, 0.022 moles of the unknown metal was plated onto his ring and the mass of the ring increased to 3.952 g. What is the atomic weight of the unknown metal in g/mol

Answers

Answer:

115 g/mol

Explanation:

Step 1: Given data

Initial mass of the earring (mi): 1.41 gFinal mass of the earring (mf): 3.952 gMoles of the unknown metal deposited (n): 0.022 mol

Step 2: Calculate the mass of the unknown metal deposited

An earring is plated in an electrolytic cell. The mass of the unknown metal deposited can be calculated using the following expression.

m = mf - mi

m = 3.953 g - 1.41 g

m = 2.54 g

Step 3: Calculate the molar mass (M) of the unknown metal

0.022 moles of the metal have a mass of 2.54 g. The molar mass of the metal is:

M = m/n

M = 2.54 g / 0.022 mol

M = 115 g/mol

according to the law of energy conservation, the total amount of energy is constant, then why does the chemical energy in electric cells got used up?

Answers

Answer:

The law of conservation of energy states that energy can neither be created nor destroyed - only converted from one form of energy to another.

Explanation:

This means that a system always has the same amount of energy unless it's added from the outside. is the total internal energy of a system.

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