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3 years ago

The value of delta G at 141.0 degrees celsius for the formation of phosphorous trichloride from its constituent elements,

Chemistry

1 answer:

AURORKA [14]3 years ago

6 0

Answer:

The correct answer is option E.

Explanation:

The Gibbs free energy is given by expression:

ΔG = ΔH - TΔS

ΔH = Enthalpy change of the reaction

T = Temperature of the reaction

ΔS = Entropy change

We have :

ΔH = -720.5 kJ/mol = -720500 J/mol (1 kJ = 1000 J)

ΔS = -263.7 J/K

T = 141.0°C = 414.15 K

$\Delta G = -720500 J/mol - (414.15 K\times (-263.7 J/K))$

$= -611,288.64 J/mol = -611.28 kJ/mol\approx -611.3 kJ/mol$

The Gibb's free energy of the given reaction at 141.0°C is -611.3 kJ/mol.

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The radius of an indium atom is 0.163 nm. If indium crystallizes in a face-centered unit cell, what is the length of an edge of

adoni [48]

<u>Answer:</u> The edge length of the unit cell is 0.461 nm

<u>Explanation:</u>

We are given:

Atomic radius of iridium = 0.163 nm

To calculate the edge length, we use the relation between the radius and edge length for FCC lattice:

$a=2\sqrt{2}R$

Putting values in above equation, we get:

$a=2\sqrt{2}\times 0.163=0.461nm$

Hence, the edge length of the unit cell is 0.461 nm

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3 years ago

Propose a method for determining the specific heat for a metal like sodium which reacts violently with water.

nalin [4]

You can put a known amount sodium into some sort of time release mechanism such as a pill made from soluble material. Then you can place the sodium into a calorimeter with a known mass of water and record the temperature change the water undergoes during the reaction. Then you can use the equation q(water)=m(water)c(water)ΔT to find the amount of heat absorbed by the water. since the amount of heat absorbed by the water is the amount of heat released from the sodium, q(sodium)=-q(water). Than you can use the equation q(sodium)=m(sodium)c(sodium)ΔT and solve for c(sodium)

I hope this helps and feel free to ask about anything that was unclear in the comments.

4 0

3 years ago

Name and describe three measures of central tendency used to summarize data.

Yuliya22 [10]

The answer is mean,mode and median

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3 years ago

When a 12.8 g sample of KCL dissolves in 75.0 g of water in a calorimeter the temp. drops from 31 Celsius to 21.6 Celsius. Calcu

Delicious77 [7]

Answer:

Step 1: Calculate qsur (the surrounding is

usually the water)

qsur = ? J

m = 75.0 g water

c = 4.184 J/g

ΔT = (Tfinal- Tinitial)= (21.6 – 31.0) = -9.4 oC

qsur = m · c · (ΔT)

qsur = (75.0g) (4.184 J/g

oC) (-9.4 oC)

qsur = - 2949.72 J

First, using the information we know that we

must solve for qsur, which is the water. We know

the mass for water, 75.0g, the specific heat of

the water, 4.184 j/g

c, and the change in

temperature, 21.6-31.0 = -9.4 oC. Plugging it

into the equation, we solve for qsur.

Step 2: Calculate qsys qsys = - (qsur)

qsys = - (- 2949.72 J)

qsys = + 2949.72

In this case, the qsur is negative, which means

that the water lost energy. Where did it go? It

went to the system. Thus, the energy of the

system is negative, opposite, the energy of the

surrounding.

Step 3: Calculate moles of the substance

that is the system

Given: 12.8 g KCl

Mol system = (g system given)

(molar mass of system)

Mol system = (12.8 g KCl)

(39.10g + 35.45g)

Mol system = 12.8 g KCl

74.55 g

Mol system = 0.172

Here, we solve for the mol in the system by

using the molar mass of the material in the

system.

Step 4: Calculate ΔH ΔH = q sys .

Mol system

ΔH= + 2949.72 J

0.172 mol

ΔH= +17179.81 J/mol or +1.72 x 104

J/mol

i hope this helps

7 0

3 years ago

Witch best describes the storage of the genetic code

natulia [17]

Answer:

The genetic code is stored in the DNA. DNA is a molecule formed by a sugar, deoxyribose, a phosphate group and four combined nitrogen bases: Adenine (A), Thymine (T), Cytosine (C) and Guanine (G). A gene is a part of DNA.

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3 years ago