Assume that silver and gold form ideal, random mixtures. Calculate the mass of pure Ag needed to cause an entropy increase of 20 J/K when mixed with 100g of pure Au

Answers

Answer 1

Answer:

[tex]m_{Ag}=2,265.9g[/tex]

Explanation:

Hello!

In this case, since the definition of entropy in a random mixture is:

[tex]\Delta S=-n_TR\Sigma[x_i*ln(x_i)][/tex]

For this silver-gold mixture we write:

[tex]\Delta S=-(n_{Au}+n_{Ag})R\Sigma[\frac{n_{Au}}{n_{Au}+n_{Ag}} *ln(\frac{n_{Au}}{n_{Au}+n_{Ag}} )+\frac{n_{Ag}}{n_{Au}+n_{Ag}} *ln(\frac{n_{Ag}}{n_{Au}+n_{Ag}} )][/tex]

By knowing the moles of gold:

[tex]n_{Au}=100g*\frac{1mol}{197g} =0.508mol[/tex]

It is possible to write the aforementioned formula in terms of the variable [tex]x[/tex] representing the moles of silver:

[tex]20\frac{J}{mol}=-(0.508+x)8.314\frac{J}{mol*K} \Sigma[\frac{0.508}{0.508+x} *ln(\frac{0.508}{0.508+x} )+\frac{x}{0.508+x} *ln(\frac{x}{0.508+x} )][/tex]

Which can be solved via Newton-Raphson or a solver software, in this case, I will provide you the answer:

[tex]x=n_{Ag}=21.0molAg[/tex]

So the mass is:

[tex]m_{Ag}=21.0mol*\frac{107.9g}{1mol}\\ \\m_{Ag}=2,265.9g[/tex]

Best regards!


Related Questions

27. A compound has a mass of 2.6632 10 2 g/mol. The number of significant figures in this mass
is —
A. 2
B. 4
C. 5
D. 7

Answers

Answer:

its b  

B. 4

Explanation:

Is nuclear fission exothermic or endothermic? Explain your answer.

Answers

Answer:

Exothermic

Explanation:

Nuclear fission means splitting, so there is a lot of energy being released.

how light warms up matter​

Answers

Answer:

Tom Zepf of the physics department at Creighton University in Omaha, Neb., notes that "Sunlight heats a material such as water or a brick primarily because the long wavelength, or infrared, portion of the sun's radiation resonates well with molecules in the material, thereby setting them into motion.

branliest pls?????/

Explanation:

PRACTICE PROBLEM Two compounds, A and B, have the same molecular formula, C6H8. Both A and B react with two molar equivalents of hydrogen in the presence of platinum to yield cyclohexane. Compound A shows three signals in its broadband decoupled NMR spectrum. Compound B shows only two NMR signals. Compound A shows an absorption maximum at 256 nm, whereas B shows no absorption maximum at wavelengths longer than 200 nm. What are the structures of A and B

Answers

Answer:

See explanation

Explanation:

One basic thing that we must keep in mind is that A and B are both dienes.

The NMR spectrum and absorption maxima of A and B indicates that A may be a conjugated diene while B may be an isolated diene.

Remember that conjugated dienes shift the absorption maxima to longer wavelengths due to π - π* transition.

The two structures attached may suffice for compounds A and B

After heating the solution, you decant the liquid and wash the remaining solid with distilled water. What you are removing by this washing?

Answers

Answer:

The solvent

Explanation:

After the solid is recoverd by decanting the liquid, some solvent particles may still adhere to the solid.

In order to remove the solvent that may have adhered to the solid completely , the solid is washed before it is now dried.

In order to remove the remaining liquid present the solid material.

We are washing the solid in order to remove the liquid particles that is attached to the solid material with the help of water. Water is a universal solvent that dissolve large number of solutes in it.

Water removes the liquid from the solid by attaching with that liquid or dissolving in it so that's why we use water for washing a solid in order to remove the impurities from the solid material in which it is placed.

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Which of the items below is a colloid?
a.fruit salad b.gelatin c.lacquer​

Answers

Answer:

b. gelatin

Explanation:

a homogeneous noncrystalline consisting of large molecules or ultramicroscopic particles of one substance.

Wht is 30.00 grams of H3PO4

Answers

Answer:

0.31 mol

Explanation:

Two elements in the same period have the same number of _____ _____ in their electron clouds.

Answers

Answer:

outer electrons

Explanation:

Answer:

Energy levels

Explanation:

Give the spectator ions for the reaction that occurs when aqueous solutions of H2SO4 and KOH are mixed.

a. OH- and K+
b. H+ and SO4-2
c. K+ and SO4-2
d. H+ and OH-
e. No spectator ions are present.

Answers

Answer:

Option C. K⁺(aq) and SO₄²¯(aq)

Explanation:

We'll begin by writing the ionic equation between H₂SO₄ and KOH.

This is illustrated below:

In solution, H₂SO₄ and KOH will dissociate as follow

H₂SO₄ (aq) —> 2H⁺ (aq) + SO₄²¯ (aq)

KOH (aq) —> K⁺ (aq) + OH¯ (aq)

Thus, aqueous H₂SO₄ and KOH will react as follow:

H₂SO₄ (aq) + 2KOH (aq) —> K₂SO₄ (aq) + 2H₂O (l)

Ionically:

2H⁺(aq) + SO₄²¯(aq) + 2K⁺(aq) + 2OH¯(aq) —> 2K⁺(aq) + SO₄²¯(aq) + 2H₂O (l)

The spectator ions are those ions that appear on both sides of the equation.

From the above ionic equation, the spectator ions are:

K⁺(aq) and SO₄²¯(aq)

A sample of sodium bicarbonate is placed in an evacuated container at allowed to reach equilibrium. What will be the total pressure?

Answers

Complete Question

Sodium carbonate, Na2CO3(s), can be prepared by heating sodium bicarbonate, NaHCO3(s).

2NaHCO3(s) ------> Na2CO3(s) + CO2(g) + H2O(g) Kp = 0.23 at 100oC

If a sample of NaHCO3 is placed in an evacuated flask and allowed to achieve equilibrium at 100oC, what will the total gas pressure be?

Answer:

The value is  [tex]P_T  = 0.959 \  atm [/tex]

Explanation:

From the question we are told that

   The equation is  

[tex]2NaHCO_3_{(s)} \rightarrow  Na_2CO_3_{(s)} + CO2_{(g)} + H2O_{(g)}[/tex]

Generally the equilibrium partial pressure is mathematically represented as

    [tex]K_p =  P_{CO_2} + P_{H_2O}[/tex]

Here  

   [tex] P_{CO_2} \ and  \  P_{H_2O}[/tex] are partial  pressures of  [tex] CO_2 \ and  \ H_2O [/tex] gases

Note: when writing the formula for equilibrium partial pressure we consider only the gas in the reaction

Let assume that    

    [tex]P_{CO_2} =  a[/tex]

Generally  [tex]P_{CO_2} = P_{H_2O}[/tex] since they are both products of the reaction

  So  

       [tex]K_p =  a^2 [/tex]

From the question we are told that [tex]K_p =  0.23 [/tex]

So  

     [tex] 0.23=  a^2 [/tex]

=>  [tex] a = \sqrt{0.23} [/tex]

=>  [tex] a = \sqrt{0.23} [/tex]

=>  [tex] a = 0.4796  \ atm [/tex]

So

     [tex]P_{CO_2} =  0.4796  \ atm[/tex]

and

      [tex]P_{H_2O} =  0.4796  \ atm [/tex]

So the total pressure is

      [tex]P_T  =  0.4796  +  0.4796[/tex]

=>   [tex]P_T  = 0.959 \  atm [/tex]

which of the following determines an object’s ability to float in water?

a. how much the object weighs
b. what the mass of the object is
c. how dense the object is
d. the volume of the object

Answers

Density of the object! :)
A. because it object is weighs

Which of the following elements has the largest atomic radius? Bromine, Barium, Magnsium, Zinc

Answers

Answer:

Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.

Explanation:

Calculate the equilibrium concentration of H3O in the solution if the initial concentration of C6H5COOH is 0.056 M . Express your answer using two significant figures.

Answers

Answer:

1.9 × 10⁻³ M

Explanation:

Step 1: Write the acid ionization of benzoic acid

C₆H₅COOH(aq) + H₂O(l) ⇄ C₆H₅COO⁻(aq) + H₃O⁺(aq)

Step 2: Calculate the acid ionization constant (Ka) of benzoic acid

The pKa of benzoic acid is 4.20

pKa = -log Ka

Ka = antilog -pKa = antilog -4.20 = 6.31 × 10⁻⁵

Step 3: Calculate the equilibrium concentration of the hydronium ion

Considering that the initial concentration of the benzoic acid is Ca = 0.056 M, we can calculate the equilibrium concentration of the hydronium ion using the following expression.

[H₃O⁺] = √(Ca × Ka) = √(0.056 × 6.31 × 10⁻⁵) = 1.9 × 10⁻³ M

A dolphin can travel 30 miles in 2 hours. What is the dolphin's speed (Remembers = d+t)

Answers

15 mph I think iajhus

Answer:

The dolphin's fast cruising speed (a travelling speed they can maintain for quite a while) is about 3-3.5 m/s (6-7 knots, 11-12.5 km/hr)

Explanation:

so 37 kilometers

Which pair of elements will form a covalent bond?

Answers

hydrogen and chlorine

What volume (in mL) will a sample of F2 gas occupy in a syringe at 5.5 atm, if the F2 has a volume of 25.0 mL at 1.2 atm?

Answers

Answer:

5.45mL

Explanation:

Using Boyle's law equation:

P1V1 = P2V2

Where; P1 = initial pressure

P2 = final pressure

V1 = initial volume

V2 = final volume

According to this question, P1 = 1.2atm, V1 = 25mL, P2 = 5.5atm, V2 = ?

1.2 × 25 = 5.5 × V2

30 = 5.5V2

V2 = 30/5.5

V2 = 5.45mL

Therefore, 5.45 mL sample of F2 gas will occupy a syringe at 5.5atm.

27.8 mL solution of 0.797 M HCHO2 with 0.928 M NaOH. What is the pH for the solution at the equivalence point in the titration?

Answers

Answer:

8.69 is the pH at the equivalence point

Explanation:

Formic acid, HCHO₂, reacts with NaOH as follows:

HCHO₂ + NaOH → NaCHO₂ + H₂O.

At the equivalence point you will have in the reaction just NaCHO₂ and H₂O. The concentration of NaCHO₂ will be:

Moles: 0.0278L * 0.797mol/L = 0.02216moles

To reach the equivalence point it is necessary to add:

0.02216mol * (1L / 0.928mol) = 0.0239L

Total volume in the equivalence point:

0.0278L + 0.0239L = 0.0517L

Concentration: 0.02216moles / 0.0517L = 0.429M

The equilibrium of NaCHO₂, CHO₂⁻, in water is:

CHO₂⁻(aq) + H₂O(l) ⇄ OH⁻(aq) + HCHO₂(aq)

Where Kb, 5.56x10⁻¹¹ is defined as:

5.56x10⁻¹¹ = [OH⁻] [HCHO₂] / [CHO₂⁻]

In the equilibrium, it is produced X OH⁻ and HCHO₂, and as concentration of NaCHO₂ is 0.429M:

5.56x10⁻¹¹ = [X] [X] / [0.429M]

2.383x10⁻¹¹ = X²

4.88x10⁻⁶ = X = [OH⁻]

As pOH = -log [OH⁻]

pOH = 5.31

And pH = 14 - pH

pH = 8.69 is the pH at the equivalence point

A block of lead weighs 11.3 grams. How many atoms of lead are in this sample?
• Use 6.022 x 1023 mol
for Avogadro's number.​

Answers

Answer:

To get the number of atoms in this sample, we first need the number of moles of lead in 11.3 grams

Number of moles of Lead:

Molar mass of lead = 207 grams / mol

Number of moles  = given mass / molar mass

Number of moles = 11.3 / 207

Number of moles = 0.05 moles

Number of atoms of lead in 11.3 gram sample:

Number of atoms = Number of moles * avogadro's number

Number of atoms = 0.05 * 6.022 * 10²³

Number of atoms = 5 * 10⁻² * 10²³ * 6.022

Number of atoms = 30.11 * 10²¹

11.3 g block of lead contains 3.29×10²² atoms

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ atoms. Thus,

1 mole of lead = 6.022×10²³ atoms

Recall:

1 mole of lead = 207 g

Thus,

207 g of lead = 6.022×10²³ atoms

With the above information in mind, we can obtain the number of atoms in 11.3 g block of lead as illustrated below:

207 g of lead = 6.022×10²³ atoms

Therefore,

11.3 g of lead = (11.3 × 6.022×10²³) / 207

11.3 g of lead = 3.29×10²² atoms

Thus, 11.3 g block of lead contains 3.29×10²² atoms

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Pls, Help ASAP with 30 points!!!
Describe the similarities and differences between the eruptions of
less gassy and more gassy magma.

Answers

Answer:

the difference is tyat eruptions of less gassy and more gassy is that the less gassy doesnt retain as much gas as the more gassy one and thus the eruption of the less gassy is less damage to the more gassy

what is the relationship between the atomic number and the melting and boiling point

Answers

Answer:

As the atomic number of elements increases, the melting point increases because there are more electrons around the nucleus, which creates a stronger negatively-charged force. With stronger forces, the melting point rises. 3. Non-metals usually have low melting points.

Explanation:

The melting point rises as the atomic number of elements increases because there are more electrons surrounding the nucleus, creating a stronger negatively charged force. The melting point rises as the forces become stronger.

What is nucleus?The nucleus is made up of protons, which are positively charged, and neutrons, which are electrically neutral. Quarks are particles that make up protons and neutrons. The nucleus (plural, nuclei) is a positively charged region in the atom's center. It is made up of two types of subatomic particles that are tightly packed together. Protons, which have a positive electric charge, and neutrons, which have a neutral electric charge, are the particles. The nucleus is the most important component of the cell (plural: nuclei). It is derived from a Latin word that means "nut kernel." Definition of Nucleus: A nucleus is a double-membraned eukaryotic cell organelle that contains genetic material.

To learn more about nucleus, refer to:

https://brainly.com/question/14110259

#SPJ2

A girl goes to the doctor because she is dealing with a terrible case of acne. The doctor tells her it is due to clogged ducts. Which gland is most likely having a problem?

sebaceous

adrenals

pineal

thyroid

Answers

Answer:

Sebaceous

Explanation:

Answer:

Sebaceous

Explanation:

Just did the assignment

An aqueous solution of Pb(NO3)2 is made by placing 275 g of solid Pb(NO3)2 into a volumetric flask and adding water to the 1.00 L mark (assume that 775g of water has been added to achieve this total solution volume). (Assume MW of Pb(NO3)2 = 331g/mole) A) What is the molarity (M) of this solution? B) What is the molality (m) of this solution? C) What is the mass % of Pb(NO3)2 in this solution? D) What is the mole fraction of Pb(NO3)2 present in this solution?

Answers

Answer:

A) 0.831 M

B) 1.07 m

C) 26.2%

D) 0.0189

Explanation:

A) First we convert the mass of Pb(NO₃)₂ to moles:

275 g ÷ 331 g/mol = 0.831 mol Pb(NO₃)₂

Then we divide it by the total volume (1.00 L) to calculate the molarity:

0.831 mol / 1.00 L = 0.831 M

B) We convert the grams of water to kilograms:

775 g / 1000 = 0.775 kg

Then we divide the Pb(NO₃)₂ by the kilograms of water:

0.831 mol / 0.775 kg = 1.07 m

C) We divide the mass of Pb(NO₃)₂ by the total mass of the solution:

[tex]\frac{gPb(NO_{3})_{2}}{gPb(NO_{3})_{2}+gH_{2}O}[/tex] *100% [tex]=\frac{275}{275+775}[/tex] * 100% = 26.2%

D) We calculate the moles of water:

775 g H₂O ÷ 18g/mol = 43.1 mol H₂O

Then we divide the Pb(NO₃)₂ moles by the total number of moles:

[tex]\frac{0.831}{0.831+43.1}[/tex] = 0.0189

For something to be considered
dead, it used to do what?

Answers

Answer:

breathe,eat, and drink i guess

I NEED HELP ASAP
1.Compare and contrast starch, cellulose, and glycogen. Include the monomers, function, and what type of organism they are found?
2. Describe the relationship between DNA and the structure of proteins. How might a change in the order of nucleotides result in a non-functional protein?

ANYTHING WILL HELP...WILL GIVE A BRAINLY

Answers

Answer:

the second on is, Changing the sequence of nucleotides in the DNA molecule can change the amino acids in the final protein, leading to protein malfunction. If insulin does not function correctly, it might be unable to bind to another protein (insulin receptor).

the first one is, These three polysaccharides differ in their glycosidic linkages and their functions too. Starting from the cellulose which is the monomer of beta glucose and is found in plant cell wall only. While Starch and Glycogen act as the carbohydrate reserve in plants and animals respectively. Though their chains have slight differences at the branching point, which is described below.

Explanation:

hope it helps

Convert 15.5 pounds to kilograms. Please and thank you so much!!

Answers

Answer:

7.030682 kg

hope it helps!

Answer:

7.030682

Explanation:

An atom of nitrogen gains how many electrons when it forms ionic bonds with three atoms of potassium?
A. 1
B. 2
C. 3
D. 4

Answers

The answer is C.3. 3 electrons are formed in ionic bonds.

How many milliliters of 0.500 M HBr would be required to react with 40.0 mL of 0.300 M Ca(OH)2?

Answers

Answer:

48dm³

Explanation:

Given reaction:

                  Ca(OH)₂ + 2HBr →  CaBr₂ + 2H₂O

Parameters:

Concentration of HBr = 0.5M

 Volume of Ca(OH)₂ = 40mL

 Concentration of  Ca(OH)₂ = 0.3M

Solution:

To solve this problem, we are going to use the mole concept. We solve from the known specie to the unknown.

 We first find the number of moles of the known specie which is the Ca(OH)₂ ;

                number of moles  = concentration x volume

                number of moles  = 0.3 x 40 x 10⁻³ = 0.012moles

From the reaction equation;

           1 mole of Ca(OH)₂  requires 2 moles HBr

          0.012 moles of Ca(OH)₂ will require 0.012 x 2  = 0.024moles of HBr

Now,

 To find the volume of HBr;

          Volume  = [tex]\frac{number of moles }{concentration}[/tex]

          Volume  = [tex]\frac{0.024}{0.5}[/tex]   = 0.048dm³

In mL;

       Volume 0.048 x 1000 = 48dm³

An increase in temperature results in A) a decrease in the required activation energy while the reaction rate remains constant. B) an increase in reaction rate due to a decrease in the kinetic energy of the reactants. C) an increase in the rate of reaction because reactant molecules collide with greater energy. D) an increase in both the reaction rate and activation energy due to increased kinetic energy.

Answers

Answer:

C) an increase in rate of reaction because reactant molecules collide with greater energy

Explanation:

Temperature is one of the factors that affect the rate of a reaction. The rate of a reaction increases with an increase in temperature and vice versa. When the temperature of a reaction increases, the kinetic energy of the reactant molecules increases causing them to react at a faster rate.

The reactant molecules respond to an increase in temperature by colliding at a faster rate due to an increased kinetic energy between the reactant molecules.

A bomb calorimeter with a heat capacity of 837 J∘C contains 745 g of water. It burns 2.50 g C8H18 resulting in the temperature going from 15.0∘C to 33.8∘C. What is the value of the heat transferred (in kilojoules) by the reaction from the perspective of the system?

Answers

Answer:

74.3kJ are transeferred

Explanation:

In the bomb calorimeter, the burning of C₈H₁₈ is producing heat that is been absorbed for the calorimeter and the water.

Heat absorbed calorimeter:

837J/°C * (33.8°C-15.0°C) = 15735.6J

Heat absorbed water:

C*m*ΔT

C specific heat of water (4.184J/g°C), m is mass of water (745g), and ΔT change in temperature (33.8°C - 15°C = 18.8°C)

4.184J/g°C*745g*18.8°C = 58601.1J

Heat released by the reaction:

15735.6J + 58601.1J = 74336.7J

74.3kJ are transeferred

CH3F contains polar covalent bond?

Answers

Answer:

CH3F is a polar molecule due to the presence of a very electronegative fluorine (3.98) as one of the outer atoms which pulls electrons towards it inducing a partial negative charge

Explanation:

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