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2 years ago

Calculate the entropy change for the reaction: Fe2O3(s) + 2Al(s) -> Al2O3(s) + 2Fe(s)

Chemistry

1 answer:

Goshia [24]2 years ago

5 0

Answer:

ΔSº= -41,2 J/molK

Explanation:

For a general equation aA +bB → cC + dD

ΔSº= c*SºC + d*SºD - a*SºA - b*SºB

ΔSº= SºAL2O3 + 2SºFe - SºFe2O3 - 2SºAl = (51 + 54.4 - 90 - 56.6)J/molK = -41,2 J/molK

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Is acid rain a global or a regional concern ?

notsponge [240]

Explanation:

Acid rain is linked to both natural and man-made sources. Nitrogen oxides are formed through the extreme heating of air when a thunderstorm produces lightning. ... For this reason, acid rain is considered a global problem

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2 years ago

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Which statement is true concerning energy

slava [35]

What are the statements ?

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2 years ago

I need help with 1,2,3, and 4

Schach [20]

Answer:

Problem 1: 1.85atm

Problem 2: 110mL

Problem 3: 290 mL

Problem 4: 1.14 atm

Explanation:

Problem 1

1. Data

a) P₁ = 3.25atm

b) V₁ = 755mL

c) P₂ = ?

d) V₂ = 1325 mL

r) T = 65ºC

2. Formula

Since the temeperature is constant you can use Boyle's law for idial gases:

$PV=constant\\\\P_1V_1=P_2V_2$

3. Solution

Solve, substitute and compute:

$P_1V_1=P_2V_2\\\\P_2=P_1V_1/V_2$

$P_2=3.25atm\times755mL/1325mL=1.85atm$

Problem 2

1. Data

a) V₁ = 125 mL

b) P₁ = 548mmHg

c) P₁ = 625mmHg

d) V₂ = ?

2. Formula

You assume that the temperature does not change, and then can use Boyl'es law again.

$P_1V_1=P_2V_2$

3. Solution

This time, solve for V₂:

$P_1V_1=P_2V_2\\\\V_2=P_1V_1/P_2$

Substitute and compute:

$V_2=548mmHg\times 125mL/625mmHg=109.6mL$

You must round to 3 significant figures:

$V_2=110mL$

Problem 3

1. Data

a) V₁ = 285mL

b) T₁ = 25ºC

c) V₂ = ?

d) T₂ = 35ºC

2. Formula

At constant pressure, Charle's law states that volume and temperature are inversely related:

$V/T=constant\\\\\\\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}$

The temperatures must be in absolute scale.

3. Solution

a) Convert the temperatures to kelvins:

T₁ = 25 + 273.15K = 298.15K

T₂ = 35 + 273.15K = 308.15K

b) Substitute in the formula, solve for V₂, and compute:

$\dfrac{V_1}{T_1`}=\dfrac{V_2}{T_2}\\\\\\\\\dfrac{285mL}{298.15K}=\dfrac{V_2}{308.15K}\\\\\\V_2=308.15K\times285mL/298.15K=294.6ml$

You must round to two significant figures: 290 ml

Problem 4

1. Data

a) P = 865mmHg

b) Convert to atm

2. Formula

You must use a conversion factor.

1 atm = 760 mmHg

Divide both sides by 760 mmHg

$\dfrac{1atm}{760mmHg}=\dfrac{760mmHg}{760mmHg}\\\\\\1=\dfrac{1atm}{760mmHg}$

3. Solution

Multiply 865 mmHg by the conversion factor:

$865mmHg\times \dfrac{1atm}{760mmHg}=1.14atm\leftarrow answer$

3 0

2 years ago

A solution is prepared from 8 grams of acetic acid ( CH3COOH ) and 725 grams of water.What is the molality of this solution?0.00

Iteru [2.4K]

Answer:

its 725 grams 0.0002 725.000

Explanation:

4 0

1 year ago

Based on the information in the table, which of the following arranges the bonds in order of decreasing polarity?

patriot [66]

Polarity is the chemical property based on the electric charge and orientation of the poles. Al−O>H−Br>As−S is arranged in decreasing order of polarity. Thus, option d is correct.

<h3>What is polarity?</h3>

Polarity is a chemical property of the distribution of the electrical charges over their respective atom in the molecule joined by the bonds. The relation between the polarity and the difference in electronegativity is directly proportional.

The electronegativity difference between the elements are:

Al−O = 1.8
H−Br = 0.8
As−S = 0.4

As the electronegativity difference between Al−O = 1.8 is the highest it will have the highest polarity followed by H−Br = 0.8, and As−S = 0.4, with the lowest polarity.

Therefore, option D. Al−O>H−Br>As−S is arranged in decreasing order of polarity.

Learn more about electronegativity here:

brainly.com/question/25217877

#SPJ1

6 0

1 year ago