Questions relating to heat and its relation to other forms of energy in chemistry.

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Lewis acid-base reaction

(A) $\ce{[NiCl2(pyr)3(SMe2)] + [Mg(OH2)4(CO3)] → [NiCl2(pyr)3(OH2)] + [Mg(SMe2)(OH2)3(CO3)]}$ (B) $\ce{[PtCl2(NH3)2] + [Ca(adenine)2(NH3)2]2+ → [PtCl2(NH3)(adenine)] + [Ca(adenine)(NH3)3]2+}$ so i ...
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4answers
3k views

Hypothetical: What happens to water as pressure increases to infinity?

I've asked a similar question here but the answer given shows the behaviour of water under general conditions. I'd like to know what the behaviour of water is like as pressures increase towards ...
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0answers
19 views

How can a melting and a freezing point of ice be the same [duplicate]

How can a freezing and a melting point of ice be the same ??
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1answer
27 views

Do liquid O2 and N2 form ideal solutions?

I suspect they do, but could not find data on this. (I mean at temperatures near those used in the distillation of liquid air.)
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3answers
111 views

Since the formation of diamond from Graphite is endothermic and the entropy decreases for this process, how is it possible to make diamond?

Surely G would always be positive and thus would make it impossible to make diamond. Clearly this is not the case. But how? Would an increase or decrease in temperature aid it's formation? I think a ...
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0answers
34 views

How can -G/T and -A/T be thought of as 'disguised' entropies?

I understand that entropy is defined as $\mathrm{d}S=\mathrm{d}q/T$ for a reversible change but I fail to see why $-G/T$ and $-A/T$ can be thought of as 'disguised' entropies. This is a question on my ...
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1answer
27 views

If $ds>=dq/T$ for a spontaneous change is $ds<=dq/T$ for a non-spontaneous change and is that even possible?

I am struggling with the concept of entropy but might be on the verge of understanding it. The Clausius inequality - $ds>=dq/T$ - is true for all spontaneous changes with the equality for ...
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0answers
14 views

Find the final temperature and the amount of ice left in the system [closed]

 10 g of ice at -10°C is added to 10 g of water at 85°C. What is the final temperature and amount of ice left in the system? (System is kept inside an ideal insulator). a) 0°C, 0 g b) 0°C, 2 g c) ...
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0answers
19 views

Find the amount of moles [closed]

How can I calculate the amount of moles of water that is formed given a theoretical value of -55.90 kJ/mol $\ce{H2O}$ that is formed and from using the amount of joules of heat that is liberated.
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2answers
34 views

What does the Clausius Inequality mean in thermodynamics? (entropy)

$$\delta S\ge\frac{\delta q}T$$ I don't understand how a quantity (the change in entropy in this case) can be greater than the very thing that defines it ($\mathrm{\frac{\delta q}{T}}$). Also ...
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1answer
35 views

Thermodynamics of Solid-Liquid

If you have an ice cube in water and the ice cube does not melt after reaching equilibrium with the water, does the water have temperature 0 degrees C?
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1answer
42 views

Difference between internal energy of combustion and enthalpy of combustion?

I am having real trouble understanding the first law of thermodynamics and I think the question, below, highlights most of my issues: 1) (a) A bomb calorimeter was calibrated by igniting a 0.825 g ...
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1answer
29 views

Why it is not possible to find absolute value of internal energy?

Today in thermodynamics lecture my teacher told that it is not possible to find absolute value of internal energy so we have to calculate change in internal energy. So my question is Why it is not ...
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2answers
58 views

Combustion in a bomb calorimeter: Am I overthinking?

To generalize the problem, I will just say: 5 gram of impure ethanol(or any other type of combustible material) is placed inside a bomb calorimeter where volume is constant, if the combustion ...
3
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1answer
37 views

Transfer of energy

After completing a lab for my chemistry class I am finding it difficult to find the initial temperature of an iron nail after being heated. Procedure of the lab went as follows: heat an iron nail, ...
3
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1answer
32 views

How will liquid nitrogen affect a steel instrument's ability to function?

I want to retrieve cryotubes from the bottom of a liquid nitrogen freezer without taking all the freezer racks out and draining the liquid nitrogen. I think I can accomplish this using a tool like ...
3
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2answers
61 views

If the equilibrium constant in a reaction is greater than 1 is it possible that there are more moles of reactants than products?

I'm wondering if this is possible because could there not be a situation in which the reactants were pure solids/liquids and would therefore not contribute to the value of k but still contain more ...
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3answers
59 views

Thermodynamics: Is Isolated system possible?

I have just started learning thermodynamics. I have learned that The system which is not able to exchange energy and matter on its own with surrounding is called isolated system. I wanted to know ...
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0answers
18 views

What is the non-ideal equivalent of mass action kinetics?

Starting from the equations of mass action kinetics, one may show that (for suitably chosen numbers $A_i$), the function $\sum_i x_i(A_i + \log x_i)$ is a Lyapunov function, i.e. it decreases over ...
3
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1answer
59 views

Conditions for spontaneity

So the two conditions for a reaction to be spontaneous are: tendency to achieve minimum energy tendency to achieve maximum randomness. Both these things are contrasting and the only way I see them ...
2
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3answers
63 views

change in enthalpy

Just going through my thermodynamics chapter I came across 2 contrasting statements. 1)change in enthalpy=enthalpy of (products-reactants) at constant pressure and temperature. 2)change in ...
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1answer
30 views

Enthalpy(H) formula: what is the pressure volume product

$$\mathrm{H=U+PV}$$ Above is the formula for enthalpy- or, the sum of the internal energy and pressure volume product. $\mathrm{- P\Delta V}$ is work done by or on the system. But $\mathrm{PV}$, ...
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1answer
19 views

Bomb calorimeter and heat capacity of calorimeter

Can anyone describe the process through which we determine the heat capacity of calorimeter, for me? The formula is $q_{calorimeter} = C_{calorimeter} \times \Delta T$ The heat of bomb calorimeter ...
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1answer
126 views

Validity of Trouton's Rule

I would like to know under what circumstances is Trouton's rule obeyed by liquids and why certain systems i.e. substances may deviate from Trouton's rule. By the way I know what Trouton's rule is ...
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1answer
52 views

Why is the Standard enthalpy of formation of O2 and other reference forms of element zero?

Well, from what I know bonding releases energy. And does anybody know a source for finding the reference form of element at standard conditions?
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1answer
29 views

Concept of heat of reaction in a isolated system

One description of the concept is that heat of reaction (exothermic) is the quantity of heat that would given off to the surrounding by the product of a reaction if we allow the product to cool down. ...
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0answers
25 views

heat released from combustion of ethane

What will be the heat released when 4.42g of ethane is combusted at 298 K and 1 atm pressure?
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1answer
72 views

What is the entropy of mixing of two ideal gases starting out with different pressures?

The entropy of mixing of ideal gas is given by this equation: $\Delta S_{mix} = -nR(x_1\ln x_1 + x_2\ln x_2)$ Does this equation works only when the initial conditions of both compartments are at ...
3
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1answer
182 views

Why do we use dG < 0 to describe a spontaneous process?

With something like a reaction or phase change, all sources use the criterion that $dG < 0$ for the reaction to be spontaneous and then substitute an appropriate expression for $dG$ to the specific ...
3
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1answer
36 views

SI Units for Isothermal Incompressibility and Specific heat capacity at constant volume

I am looking for the SI units of Isothermal Incompressibility and Specific heat capacity at constant volume. What I found was that Isothermal compression was measured in $\frac{m^2}{N}$ so I'm ...
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1answer
58 views

Proof of kinetic energy equation

Is there a way to prove that $\frac{1}{2} mv^2 $$= \frac{3}{2}RT$ The first one is kinetic energy and the second is the average kinetic energy. Can this be proved by component of velocity.
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1answer
176 views

A thermos bottle containing milk is shaken vigorously

I have a conceptual physical chemistry question here. A thermos bottle containing milk is shaken vigorously. Consider the milk as the system. Will the temperature rise as a result of the shaking? ...
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1answer
50 views

Finding the equilibrium temperature between two substances in a constant pressure calorimeter

I need to find the temperature two things equilibrate to in a constant pressure calorimeter given only their specific heats, masses, and starting temps. The only thing I know for specific heat is ...
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1answer
45 views

Relation between thermodynamic reversible process and reversible reaction

I know it seems to be a weird question. But for long I have been thinking whether there is any relation between thermodynamic reversible process and reversible reaction. Do they have any connection ...
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1answer
126 views

A contradiction, probably from confusion

All things in nature tells us that high entropy is easier to happen. But then why does it takes energy to break bonds, in order to achieve high entropy. Any thing in gaseous state has higher ...
3
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1answer
44 views

Significance of Kinetic Velocities?

In the concept of Kinetic Molecular Theory we have rms(root mean square), avg(average) and mp(most probable) velocities. I understand the concept well. But my question is why do we have three ...
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2answers
125 views

How can a protein folding transition state have zero lifetime?

I'm doing a module on my Biochemistry course looking at protein folding, and in a discussion of [folding] transition states I was a little confused at the thought of a zero-lifetime transition state - ...
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0answers
49 views

Heat of combustion for Octane

I'm a Mechanical Engineering student and I have been working on a school project but I want to go a bit beyond that and it has led me here. I'm designing an engine cylinder, and I figured I should be ...
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2answers
143 views

Problem with thermodynamic reversible processes?

My book says 'Maximum work can be obtained only from thermodynamically reversible processes,' but why is it so? What is the cause? Actually to me the definition of reversible process is confusing. ...
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3answers
69 views

What is the lower bound to the temperature at which a fire can burn?

To have a fire, you need 1) oxygen, 2) fuel and 3) heat. You can have different fuels that burn at different temperatures, but you always need some amount of heat to have a fire. If you can use any ...
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1answer
29 views

Dry adiabatic lifting

If an unsaturated air parcel ascends adiabatically in the atmosphere with an initial temperature, would the final temperature of the air parcel, when it reaches it's destination, be the same at the ...
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1answer
32 views

Specific volume of an air parcel

So I have an unsaturated air parcel in the atmosphere that ascends adiabatically from the $1000$ mb level to the $700$ mb level with its initial temperature being $10$ degrees Celsius. I have to find ...
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1answer
63 views

Gibbs free energy of chemical compounds

How the Gibbs free energy of a chemical compound is theoretically calculated from scratch? When saying that the Gibbs free energy of NaCl is -384.1 kJ/mol, this value is related to the chemical ...
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1answer
30 views

Can we determine apriori the volume of solvent in an electrolyte

Suppose I would like to create a one molar solution of NaCl in water. The molar concentration is defined as $c_i=\frac{n_i}{V} $ $n_i=1$ in this case. I need to take 58.5 grams of NaCl (atomic ...
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1answer
43 views

Nature of spontaneous reactions

The definition of spontaneous process states that "A spontaneous process is an irreversible process and maybe reversed by some external agency" So, can we say that all spontaneous reactions are ...
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2answers
153 views

Derivation of the relation between temperature and pressure for an irreversible adiabatic expansion

I have a formula for finding the final temperature in an irreversible adiabatic expansion. $$T_2=\left[\frac{C_v+(\frac{P_2}{P_1})}{C_p}\right]T_1$$ where $T_1$ is the initial temperature. $C_v$ and ...
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2answers
58 views

Can lattice enthalpy only be determined by the Born-Haber cycle?

Since we are able to determine the enthapy of formation experimentally, why it is impossible to determine the lattice enthalpy directly by experiment?
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1answer
69 views

Correlation between the virial coefficients and a & b in the corresponding Van Der Waals equation of state

I don't know where to begin with this question. A function f(x) can be expressed as a special power series called the Taylor expansion. The common expansion is $(1-x)^{-1}=1+x+x^2$ Note that the ...
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0answers
37 views

How fast will hydrazine boil out of a tube into a vacuum?

For context I'm talking about ISEE-3 and how long it would take to dump the now useless and hazardous fuel it still carries. Given a heated tank of hydrazine (somewhere near $0~^\circ\mathrm{C}$) ...
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1answer
49 views

Is sign convention for delta H and enthapy change of a solution different?

I have got some confusion . In the Ncert Chemistry Tb , it is given in bold that $\Delta H$ is negative for exothermic reactions which evolve heat during the reaction and $\Delta H$ is positive for ...