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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2
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1answer
92 views

How do fullerenes withstand external pressure from collapsing the molecule?

As Fullerene's have an empty shell inside their structure how they withstand the pressure from the outside? As a sidetone, are there any methods for calculating the force that the "vacuum" ...
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0answers
43 views

What will happen to a diamond if put through its birth or grow process? [closed]

What will happen to a lab grown diamond if put through its grow process a second time? I mean swapping the diamond seeds for a diamond.
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1answer
106 views

Find gas pressures of injection knowing mixture pressure without knowing volume

Let's say we have a gas 1 moving inside a pipe (we don't know the geometry) at mass flow rate $Q_1$ and temperature $T_1.$ We inject a gas 2 at some point inside the pipe with gas 1 at mass flow rate $...
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7k views

At what pressure will hydrogen start to liquefy at room temperature?

I want to increase a fixed-size object's internal gas pressure by generating hydrogen in it, but I could not find the proper phase diagram for it. So I am wondering how high pressures I can get.
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1answer
77 views

Does the vapor pressure of a substance depend on the presence of other gases?

The Clausius-Clapeyron equation (CC equation) can be used to find the (saturated) vapor pressure of a substance ie. the gas pressure at which the two phases (vapor + liquid or vapor + solid) reach ...
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1answer
55 views

How does hydraulic equilibrium work on the particulate level?

I recently learned that osmosis occurs when there is a semipermeable membrane between pure water and a solution of water. The pure water then fills up the solution's side until, as my textbook put it, ...
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0answers
20 views

Why is my P-T gradient decreasing for increasing radius of spheres when it should be increasing? [closed]

Why is my P-T gradient decreasing for increasing radius of spheres when it should be increasing? I'm simulating some hard sphere collisions with $Radius_{container}=10,$ and varying pressure and ...
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3answers
5k views

Does the rate constant depend on pressure?

I have read in some books that when pressure increases, the number of effective collisions increases. Hence, $k$ depends on pressure. Is it true? If so, then why doesn't $k$ depends on concentration? ...
3
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1answer
2k views

What is the temperature at which lava evaporates?

According to this article -> http://ntrs.nasa.gov/search.jsp?R=19660041998 Lava evaporates under natural conditions, but apparently, only a little bit. I'd like to know the temperature at which ...
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1answer
37 views

What causes water to condense when air pressure is reduced?

In this video: https://youtu.be/IyBRGhXBuGw The cabin pressure is reduced and subsequently a mist is formed. What exactly is the cause?
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1answer
48 views

Do solids in a solution also apply partial pressure? If yes, can this be used as an intuitive explanation for osmosis?

I know that in a mixture of different gases, we can assign every type of gas molecules a partial pressure so that the total pressure is the sum of all partial pressures. This can be extended to gas ...
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1answer
67 views

Ideal Gas Equation Extreme Case [closed]

I have recently learned about the Ideal Gas Equation and I have this doubt.....suppose I am in a closed container filled with a gas of fixed volume and definite amount of moles. I am assuming myself ...
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1answer
28 views

What would happen if I increase the pressure and temperature of a gas present in a container

Assume the gas to be a real gas and the container to be made of diamond or anything stronger than that. Take the amount of gas to be 2mL and the pressure is increased with the help of strongest ...
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3answers
510 views

Pressure-dependence of electrolysis voltage

I'm trying to better understand electro-chemistry, so please explain why this second-kind perpetual motion device won't work. I guess it's safe to assume it won't work one way or another. There is a ...
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4answers
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Pressure vs volume plot for real gas and ideal gas

Background Recently I have been studying about the states of matter and came to the topic of ideal gases and real gases, and the laws related to them. While studying it from my textbook, I saw the ...
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0answers
61 views

Density and partial pressure [closed]

A sample of $\ce{NOBr}$ gas was placed in a rigid flask where it decomposes at $\pu{25 ^\circ C}$ according to the following reaction: $$\ce{2NOBr(g) <=> 2NO(g) + Br2(g)}$$ At equilibrium, the ...
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1answer
47 views

What's the equilibrium pressure of CO2 gas over sodium hydroxide?

Many (too many) decades ago in physical chemistry lessons, I seem to recall that given the enthalpy changes of reactions, and maybe phase diagrams, one could work out what equilibrium a reaction would ...
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1answer
75 views

Variation of vapour pressure with application of external pressure

Many times study of fact that with pressure of a substance only depends on the temperature and nature of the substance recently I study about dew point and bubble point. Then I came up with this ...
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2answers
120 views

Why does van der Waals' equation of state give only one P, V pair for a particular temperature here?

I came across this question which I initially ignored believing that the data was insufficient: Calculate the pressure exerted by one mole of $\ce{CO2}$ gas at $\pu{273 K}$ if the van der Waals' ...
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1answer
100 views

Dissolution of CO2 in water

The following question has troubled me for a while. For gases that are slightly soluble in water, there is a proportional relationship between the partial pressure, $P$, and the mole fraction, $x$, ...
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0answers
73 views

Molecular orbitals energy under pressure

Suppose we have a hydrogen molecule $\ce{H2}.$ At room temperature the average distance of the nuclei is $r_0$ (without applying pressure). If we put $n$ hydrogen molecules in a box with volume $V_\...
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2answers
88 views

Why does CO2 diffuse out of a cylinder in the absence of a pressure difference?

Suppose I have a thermally insulated cylinder containing carbon dioxide (assuming it is ideal) at 1 atm pressure(atmospheric pressure is 1 atm). Now let's consider two cases: CASE-1: I cut open the ...
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1answer
199 views

How to calculate Kp without knowing the volume? [closed]

I have the following chemical equation: $$\ce{Sb2S3 + 3H2 <=> 2 Sb + 3H2S}$$ I have $\pu{1000 grams}$ of $\ce{Sb2S3}$ that reacts with $\pu{10 grams}$ of $\ce{H2}$ in a reactor at $\pu{713 K}$. ...
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14 views

Heat released at constant pressure and temperature and heat released at constant density and temperature

Is there a relation between heat released at constant pressure and temperature and heat released at constant density and temperature? I was reading some books on propulsion and combustion, and the ...
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1answer
79 views

Effect of addition of inert gas on concentration in an equilibrium [duplicate]

We have the following equilibrium established in a container with movable piston at atmospheric pressure. $$\ce{N_2 (g) + 3 H2 (g) ⇌ 2NH_3 (g)}$$ Now how does the concentration of the reacting species ...
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1answer
39 views

Vapor Pressure of reaction mass undergoing an exothermic reaction

A vessel containing a reaction mass under going an exothermic reaction is under vacuum, with temperature and pressure constant. When the source of vacuum is closed, the reactor begins to increase ...
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1answer
67 views

Finding equilibrium constant for the reaction between non-stoichiometric mix of gaseous components

$$\ce{CH3OH(g) + NOCl(g) <=> CH3ONO(g) + HCl(g)}$$ The volume of the container is $\pu{433 cm^3},$ $T = \pu{50 °C}.$ Methanol was added until the pressure was $\pu{50.1 mbar},$ then $\pu{0.059 g}...
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1answer
801 views

calculate the pressure at equilibrium

Given that $K=18$ for the equilibrium below, calculate the total pressure in a sealed vessel initially containing only $\ce{NH4I(s)}$, that reaches equilibrium. $$\ce{NH4I(s) \leftrightharpoons NH3(g) ...
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1answer
882 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{...
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1answer
569 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\,...
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1answer
1k views

Osmotic Pressure

If the osmotic pressure of a 0.010 M aqueous solution of sucrose at 27˚C is 0.25 atmosphere, then the osmotic pressure of a 0.010 M aqueous solution of NaCl at 27˚C is (a) 0.062 atm (b) 0.12 atm (c)...
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1answer
645 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 ...
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1answer
1k views

Calculating the equilibrium constants for parallel reactions

So, I am attempting to calculate the equilibrium constant for two separate reactions. $$\ce{A + B<=>C + D}$$ $$\ce{A + B <=> C + E}$$ I have figured out the final pressures at equilibrium ...
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1answer
101 views

When does a piston stop in an irreversible process?

Suppose we have an ideal gas filled inside a container fitted with a piston. The external pressure is equal to internal pressure. If we suddenly decrease the external pressure, we say that the gas ...
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2answers
114 views

Will the total equilibrium pressure increase in gas phase reaction PCl5(g) = PCl3(g) + Cl2(g) after chlorine is removed?

Will the total pressure be greater than the initial equilibrium pressure if all $\ce{Cl2}$ is removed and the following reaction is allowed to re-equilibrate? $$\ce{PCl5(g) <=> PCl3(g) + Cl2(g)}$...
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1answer
110 views

Pressure of two flasks connected to each other at different temperatures [closed]

Two flasks of equal volume connected by a narrow tube (of negligible volume) are at $\pu{27 °C}$ and contain $\pu{0.7 mol}$ of $\ce{H2}$ at $\pu{0.5 atm}$. If one of the flasks is then immersed into a ...
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1answer
107 views

Relative humidity and vapor-pressure in equilibrium

I have quite an unclear understanding of relative humidity. I am writing my understanding on the topic and please correct me wherever I'm wrong: What I understood: Let's say $\ce{H2O}$ has a (...
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2answers
977 views

Calculate the partial pressure of NO2

Calculate the partial pressure of $\ce{NO2}$. $$p_{\ce{N2}}/p_{\ce{O2}}=5$$ $$\ce{N2(g) + O2(g) <=> 2NO(g)}$$ Let’s assume $K=0.1$ $$K= \frac{p_{\ce{NO}}^2}{p_{\ce{O2}}\cdot p_{\ce{N2}}}$$ $...
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1answer
2k views

Unknown Mass in Dalton's Law of Partial Pressures

An air with mass of $0.454\ \mathrm{kg}$ and an unknown mass of $\ce{CO2}$ occupy an 85 liters tank at $2068.44\ \mathrm{kPa}$. If the partial pressure of the $\ce{CO2}$ is $344.74\ \mathrm{kPa}$, ...
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2answers
2k views

How to find the change in internal energy (q+w) for an expanding monoatomc ideal gas?

If a monoatomic ideal gas simultaneously expands against a constant external pressure and drops in temperature, how do you find the internal energy change? Known values are: $T_1$, $T_2$, $p_1$, $p_2$,...
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38 views

Osmotic Pressure of Aqueous Solution

The osmotic pressure of an aqueous solution at $25$ Celsius is $92.0$ $kPa$. Calculate the boiling point of the solution. (Assume that the density of the solution is $1.0$ $g/mL$, ignore the mass of ...
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25 views

Liquifying a gas above critical temperature [duplicate]

Is there any theoretical/hypothetical way through which a gas can be liquified above critical temperature? For example applying inifinjte amount of pressure to the system?
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1answer
107 views

Equilibrium: Effect of change in composition and value of Kp, Kc on changing pressure

Di-hydrogen gas is obtained from natural gas by partial oxidation with steam as per following endothermic reaction: $CH_4{_{(g)}}+H_2O_{(g)} \ce{<=>} CO_{(g)}+3H_2{_{(g)}}$ How will ...
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2answers
104 views

Changing pressure on equilibrium

Recently I heard my teacher say that when increasing the total pressure of the system, the reaction which is "more dependent on collisions" is favoured. This seems to make sense, although I'...
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1answer
25 views

Doesn't adding an inert gas at constant volume increase the partial pressures?

When you add an inert gas to a container of constant volume full of gases, you are basically shoving the inert gas into the container and increasing the pressure inside the container, so the partial ...
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1answer
128 views

Decarboxylation of THCA during CO2 Extraction of Cannabis

We have a strange problem. We are performing CO2 extraction on cannabis and we are seeing considerable decarboxylation of THCA to THC. We have high quality temperature sensors at the heat exchangers, ...
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1answer
61 views

What pressure does liquid nitrous oxide need at −45 °C?

What pressure does liquid nitrous oxide need at −45 °C to remain liquid? How can I calculate its pressure required for other temperatures?
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1answer
428 views

Is it possible to store moist air at high pressure?

Is there any way to store moist air inside a high pressure tank? Let's suppose that I have humid air (30%) at room temperature and I want to store it at 300Bar in a tank. when I extract the fluid from ...
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1answer
23 views

Reaction stoichiometry for calculation of Kp

NH$_2$CO$_2$NH$_4$(s)⇌$2$ NH$_3$(g)+ CO$_2$(g) I want to calculate K$_p$ for the reaction above, given that the total pressure is $0.63$ bar. My calculations: $0.63$ = p(CO$_2$) + p(NH$_3$) , where ...
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42 views

Diatomic molecule under pressure

If we put a diatomic molecule under pressure the interatomic distance will be decreased and according to this graph the potential energy of the bonding molecular orbital will be increased. What will ...

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