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Questions tagged [pressure]

For questions about gas pressure, or the effect of pressure in general on chemical species, substances, or reactions.

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5
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2answers
943 views

Calculate ozone layer thickness at a given temperature and pressure [closed]

The ozone concentration in the upper atmosphere averages $\pu{3.0 \times 10^13 molecules per cm3}$ in a region between $15$ and $\pu{35 km}$ high, at an average pressure of $\pu{0.001 atm}$ and ...
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0answers
245 views

Is brass combustible in high pressure oxygen environment?

Some metals are particularly ignitable in high pressure oxygen environments, like stainless steel and aluminum. Copper and nickel, on the other hand will self-extinguish when ignited. Does anyone know ...
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2answers
2k views

What is "chemical pressure"?

While reading some publications on solid superconductors, I encountered a term "chemical pressure" a few times, which is usually attributed to the changes of superconducting transition ...
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2answers
2k views

When two containers at different T and P are kept together, will pressure become same or temperature?

Two containers, kept at different temperatures are connected through a stopcock and two different ideal gases at different pressures are filled inside them. Initially the stopcock is closed. When the ...
5
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0answers
3k views

Effect of temperature and pressure on structure of solids

What is the effect of these conditions on the structure of solids? My book has the answer that confuses me. I got nothing about it. Can you please explain? The answer of the book is With the ...
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0answers
349 views

Why doesn't a temperature and pressure gradient exist in a container of real gas?

In the Kinetic theory of gases, it is assumed that there are no intermolecular forces between the atoms/molecules. But real gases, have intermolecular attractive and repulsive forces. Suppose a ...
15
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4answers
4k views

Aside from carbon, what other substances can be made "superhard"?

So diamonds are an allotrope of carbon, that is formed when carbon is put under immense pressure, right? What other elements or compounds can you make into "diamonds", as in more durable, harder ...
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0answers
277 views

Is OH + CO → CO2 + H an elementary reaction?

Is $$\rm OH + CO \longrightarrow CO_2 + H$$ an elementary reaction? How could I tell? I could break the reaction into $$\rm OH\ (+ M) \longrightarrow O + H\ (+ M)$$ $$\rm CO + O \longrightarrow ...
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0answers
169 views

Pressure increase due to the reaction of CaO and HNO3

Currently I'm facing difficulties in determining the pressure increase due to the reaction between $\ce{CaO}$ and $\ce{HNO3}$. To be more specific, we first fill a vessel with $\ce{H2O}$ and $\ce{CaO}$...
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1answer
452 views

Does temperature change pressure in isochoric system?

Consider the following equilibrium reaction: $$\ce{2 NOCl (g) <=> 2 NO (g) + Cl2 (g)} \qquad \Delta H > 0$$ My textbook has a statement that: If you decrease the temperature when ...
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0answers
153 views

How does Le Chatelier's principle apply to a fuel tank full of hydrogen?

A nano-tube packed fuel tank is full of Hydrogen, and there is a steady pressure of Hydrogen in the tank. While hydrogen gas is being removed from the fuel tank to power the car, the pressure in the ...
14
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3answers
9k views

Why do helium balloons expand in volume as they go higher?

I realize as balloons go higher, the atmospheric pressure decreases, doing less to counteract the force of the gas particles pushing against the inner walls of the balloon. But at the same time, doesn'...
6
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1answer
17k views

Entropy and specific heat capacity

I have seen the equation $S(T_2)=S(T_1)+C_p\ln(T_2/T_1)$ where $C_p$ is the molar heat capacity at a constant pressure. I understand that this assumes that the temperature range is sufficiently small ...
5
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2answers
5k views

How does the partial pressure of gas C change with the change in volume of the container?

Suppose I have the equilibrium in a closed container: $$\ce{3A(s) + 4B(g) -> 4C(g) + D(s)}$$ What happens to the partial pressure of C if the volume of the container is halved? I was pondering ...
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1answer
10k views

Can a liquid turn to a solid by applying pressure?

When pressure increases, volume decreases. If an extremely high pressure is applied to a liquid, is it possible to reduce it's volume to an extent where the molecules are very tight together, hence ...
2
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2answers
2k views

What pressure is created by the electrolysis of water?

I am interested to know what is a reasonable maximum working pressure I could expect against the evolution of oxygen and hydrogen when electrolysing a typical water electrolyte. My aim is to make ...
2
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1answer
285 views

How can I generate 250 GPa to create metallic hydrogen?

In the preparation of metallic hydrogen, how does one conjure up such immense pressures? I mean, I read that something like diamond anvils were used to contain the hydrogen, but now, in accordance ...
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0answers
48 views

Pressure/ vacuum on preciptation of a borax saturated solution

Trying to go back to my collage chem/physics. We put a supersaturated solution of borax on the stove. (heated water, added borax till it would not take more borax). Placed them under vacuum 15 inhg,...
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4answers
2k views

Is vapour pressure of a liquid solution constant at a given temperature, no matter the size of closed container and amount of liquid taken?

Does vapour pressure of a liquid solution depend on the size of closed container, amount of solution taken, given that, temperature is kept constant? Or will it change, if some extra gas is added to ...
6
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1answer
327 views

Are wrinkles\folds in paper reversible by heat, pressure or something else?

I ran into this question on Lifehacks.SE, regarding how to remove wrinkles from a crumpled piece of paper. Suggestions included ironing the paper or placing it under some heavy books for a few days. ...
-3
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2answers
8k views

How does equilibrium change when pressure is increased? [closed]

What happens to the equilibrium when an increase in pressure is applied to a system with the same number of moles of gas on both sides of the reaction, according to Le Chatelier's Principle? For ...
8
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4answers
10k views

Why do we use the external pressure to calculate the work done by gas

I read in a textbook that in the case when we have a gas in a cylinder fitted with a massless frictionless piston being held with an external pressure $p_1$, and when the pressure is reduced to become ...
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2answers
91 views

Understanding Avogrado's hypothesis

I have read that gases under identical conditions of temperature, pressure, and volume contain the same number of molecules, but every gas has different types of atoms so their force of attraction is ...
15
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2answers
300 views

Does exotic potassium exist?

I was reading a book called 'Hundred and Seven Stories of Chemistry'. There is a chapter about how the attributes of different elements can change in presence of enormous pressure and temperature. ...
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0answers
118 views

Find Equilibrium Constant with only balanced equation?

Calculate the value of $K_p$ for the following equation: $$\ce{PCl3 (g) + Cl2 (g) <=> PCl5 (g)} ,\qquad \mathrm{R = 0.0821 \frac{L\times atm}{mol\times K}}$$ This question appeared on my test. ...
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1answer
2k views

Osmotic pressure of a solution of a protein?

A small protein molecule, code-named "sloth", has a MM of $\mathrm{1.50 x 10^4}$ g/mol. What is the osmotic pressure exerted at $\mathrm{24.0^oC}$ by 25.0 mL of an aqueous solution that contains $\...
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1answer
357 views

What is pure oxygen (gas) density as a function of T or P?

I'm looking for a set of data (ideally graphed) of $\ce{O2}$ density as a function of $T$ or $p$ (with constant $p$ or $T$, respectively). The best I've found is this 1948 paper which provides an ...
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0answers
79 views

Are there pressure driven reactions such that the product remains stable even after it is depressurised? [closed]

High pressure chemistry tend to return compounds with very interesting and unusual bonding structures, such as $\ce{NaCl7}$, metallic hydrogen and $\ce{Na2He}$ However, for most of these, the ...
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1answer
2k views

Vapor pressure lowering

I have got this problem in my text book, Consider these three mercury manometers. One of them has 1 mL of water placed on top of the mercury, another has 1 mL of a 1 m urea solution placed ...
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1answer
563 views

Does a mixture of gases contain equal volume to that of the container they're in? Why?

In my textbook, the derivation of Dalton's Law of Partial Pressure is done by keeping the volume of a mixture of gas in a container constant which is equal to the volume of container itself. How ...
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2answers
348 views

How was the bottle crushed by air?

In this video, a water bottle is shown to be crushed by the surrounding air. My understanding: When the person pours cold water over the bottle which has hot water inside it, the hot water produces ...
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1answer
247 views

What is the variation of atmospheric pressure at large heights?

In an approximation (though not a very accurate one), temperature can be assumed constant throughout the atmosphere. The Earth's gravitational field can also be assumed constant (a better assumption). ...
2
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2answers
383 views

Finding the value of pressure equilibrium constant

Question: A rigid vessel containing only $\ce{NO2(g)}$ is heated to $\pu{337^{ \circ}C}$ and allowed to come to equilibrium according to the following reaction: $$\ce{2NO2 <=> 2NO + O2}$$ ...
2
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1answer
116 views

Determining the amount of water to create a given pressure in a sealed container

I have a sealed container with a volume of 1 liter. I want to go from an initial pressure of $P_{1}=1\ \mathrm{atm}$ and an initial temperature of $T_{1}=298\ \mathrm{K}$ to a final pressure of $P_{2}=...
3
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2answers
266 views

Can I make a container of (kind of) perpetually boiling water?

It's a common school experiment to make water boil at room temperature by putting it in a container and reducing pressure. I am wondering if it is possible to make a sealed sphere containing water ...
1
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1answer
600 views

Does lowering temperature of a gas make it easier to compress?

My teacher said that for ideal gases, the lower the temperature, the lower the kinetic energy of a gas will be, and it will be easier to compress the gas. Using the ideal gas equation $PV=nRT$, if ...
1
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1answer
532 views

Change in internal energy of a gas upon expansion against a constant external pressure

I have a question about the following problem which I got wrong: During expansion of its volume from $\mathrm{1.00\,L}$ to $\mathrm{10.00\,L}$ against a constant external pressure of $\mathrm{2.00\,...
3
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1answer
10k views

How to find the molar mass of a compound given mass, vol, temp, and pressure?

A $2.1\ \mathrm g$ sample of a liquid vaporizes and exerts $120\ \mathrm{mmHg}$ pressure at $1.5\ \mathrm L$ volume and $80\ \mathrm{^\circ C}$ temperature. Find the molar mass of the gas. I first ...
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4answers
1k views

Enthalpy of a reaction changes with temperature, does this mean bond strengths change with temperature?

During chemical reactions, the bonds between atoms break or form to either absorb or release energy. The result is a change to the potential energy of the system. The heat absorbed or released from a ...
3
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1answer
1k views

Henry's law and O2 concentration in alveoli blood

Can Henry's law be applied to find $\ce{[O2]}$ in alveoli blood? This kind of question appeared in an another forum and I've been struggling to find a definitive answer. My initial thought was 'no', ...
5
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3answers
2k views

Will supercritical nitrogen stay supercritical if we raise temperature and pressure high above critical values?

Nitrogen's critical temperature is -146.96 °C and critical pressure 33.96 bar. If we maintain nitrogen at 220 bar and 400 °C, what will be the state of $\ce{N2}$? Will it be still supercritical? I ...
3
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2answers
499 views

Is pressure equalization "diffusion"?

There is another question on the site which is: Two containers, A and B, connected by a closed valve were evacuated and the Chlorine gas (Cl2) with a pressure of 200kPa was put into A and Oxygen (...
4
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1answer
1k views

Why do gases under low pressure conduct electricity?

In J. J. Thomson's cathode ray experiment, he used a discharge tube in order to make the gas inside conduct electricity. Why do gases under low pressure conduct electricity?
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1answer
137 views

Vacuum at different altitude

I have tried to find this searching the internet and I am not sure if I understand it. I want to turn water from solid to gas without going into the liquid phase - Sublimation. The altitude above sea ...
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1answer
867 views

Van der Waals pressure

I was solving some problems and I had a doubt a problem since the resulting pressure gives me a negative value. The problem was the following: Could $100~\mathrm{g}$ of $\ce{N2}$ in a $200~\mathrm{...
3
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3answers
5k views

Gaseous State(Dalton's Law)

Why does the mixture of gases $\ce{NH3}$ & $\ce{HCl}$ not obey Dalton's Law of partial pressure at room temperature? Also, what other mixtures don't obey Dalton's Law of partial pressure
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2answers
5k views

The effect of pressure on boiling point?

My textbook states the following: Qualitatively, I understand why the boiling point of a substance increases when the pressure is increased. However, I learned that if the pressure is increased when ...
3
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2answers
4k views

Van der Waals real gas equation

Van der Waals corrected the ideal gas equation for real gases and gave the following equation: $$\left(p+\frac{an²}{V^2}\right)\left(V-nb\right)=nRT$$ I’m very confused about one aspect of this ...
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0answers
752 views

How to find pH of an aqueous ammonia solution at high pressures?

Here's the simplified question: I start with $15~\%$ of $\ce{NH_3}$ and I want to find the $\mathrm{pH}$ of the following reaction at $25~\mathrm{^\circ C}$ and $5\ \mathrm{kbar}$: $$\ce{NH_3 + H_2O -&...
4
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3answers
1k views

Why do some reactions require specific pressures to happen?

For example, carbon monoxide reacts with hydrogen to synthesize methanol in the presence of some catalysts, but the pressure needs to be $\pu{50 atm}$ and the temperature needs to be $\pu{523 K}$. ...