Questions tagged [pressure]

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

Filter by
Sorted by
Tagged with
-1
votes
0answers
16 views

pressure change when combining hydrogen sulfide and hydrogen peroxide

I periodically add 1 quart of hydrogen peroxide to a 50 gallon hot water tank in order to neutralize the hydrogen sulfide in the water and get rid of the "rotten egg" smell. My question is: ...
0
votes
0answers
39 views

How does pressure affect chemical bonding? [closed]

The molecular theory of friction says that friction arises as a result of bonding between the suface molecules in contact... When we push a body, these bonds are stretched much like in a spring and ...
2
votes
2answers
64 views

Effect on mass when decreasing pressure in equilibrium reaction

For example, if we have the reaction: $$\ce{A + B <=> C}$$ And the volume is decreased, the pressure would increase. Hence, according to Le chatelier's principle, the system will partially ...
-2
votes
2answers
53 views

Misconception of gas laws [closed]

I face a misconception with gas laws: Boyle’s law, Charles’ law, and Gay-Lussac’s law. This is because each law of these assumes the constancy of one of the three following variables (the pressure, ...
-1
votes
3answers
52 views

Can work be done on a body when temperature and pressure are changed without changing its volume?

Can work be done on a gaseous system when temperature and pressure are changed without changing it's volume? In chemistry the formula of work is always $p\,\mathrm dV,$ whereas we can also do work on ...
0
votes
1answer
49 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'...
2
votes
1answer
675 views

Can silicon dioxide melt at 20 °C?

Can $\ce{SiO2}$ melt at $\pu{20 ^\circ C}$? I have searched the web for $\ce{SiO2}$ phase diagram, but it seems to me that almost all the graph I can find have the temperature axis where the minimum ...
1
vote
0answers
36 views

Relationship between the partial pressure $p_J = x_J p$ and the perfect gas law $pV = nRT$

I am currently studying Atkins' Physical Chemistry, 11th edition, by Peter Atkins, Julio de Paula, and James Keeler. Chapter 1A.2 Equations of state says the following: When dealing with gaseous ...
5
votes
2answers
380 views

Pressure exerted by a particle of ideal gas

There is a step I fail to grasp in the proof that for a monatomic ideal gas, $U=\frac{3}{2}PV$, where $U$ denotes the internal energy of the gas. The proof involves considering a particle with mass $m$...
0
votes
1answer
25 views

How does pressure influence the dehydration of salts?

It's well known that the boiling point of a substance increases with pressure. I was wondering if something similar happens with hydrated salts and the temperature at which they dehydrate. I mean, if ...
1
vote
2answers
50 views

Can Gay-Lussac's law be observed in the reverse direction?

Gay-Lussac's law states that if you decrease the temperature of a gas at constant volume, the pressure decreases by a corresponding amount. This is easy to carry out experimentally. But in practice is ...
0
votes
1answer
52 views

Latent Heat, Vapor pressure and Equilibrium [duplicate]

So after reading about this topic i wanted to share what i learned and i wanted you guys to tell me if what i am writting is correct: A pressure vessel has propane inside and it is pressurized. The ...
2
votes
0answers
33 views

Measuring vapour pressure in a closed system

My experiment requires the determination of vapour pressure from which I will calculate the number density (or number of moles of the molecule) later, for a closed system. Here's my setup : Liquid ...
1
vote
1answer
24 views

What is the effect of pressure upon the melting and boiling points of a substance? [closed]

I want to know about the inter-relation between the effect of pressure upon the melting and boiling points of a substance. Can anyone help?
1
vote
2answers
47 views

Shouldn't the pressure of gas above a liquid slightly decrease when some of its molecules dissolves in the liquid? [closed]

Lets say a liquid and gas above are in equilibrium. (1) Now if I suddenly increase the pressure of the gas it will take some time for some molecules of the gas to enter the liquid and get dissolved. ...
-1
votes
1answer
19 views

Doubt about definition of boiling point [duplicate]

The definition of boiling point says boiling point is the temperature at which the vapour pressure of liquid becomes equal to vapour pressure of atmosphere. But how does the vapour pressure of the ...
0
votes
1answer
51 views

Why are pressure or volume not able to change the equilibrium constant? [duplicate]

It is stated in my textbook that temperature is the only factor that can change the equilibrium constant. According to the Ideal Gas Law, temperature is dependent on the pressure and volume. Thus, ...
1
vote
1answer
62 views

Clausius–Clapeyron equation: shape of phase diagrams makes no sense

I am trying to model the melting point of a substance at varying pressures (ranging from very small to very very large). All I am trying to do is make an equation that relates melting temperature to ...
3
votes
1answer
110 views

Percent degree of dissociation of gas by pressure

I stumbled across the following interesting problem: Assume that you have started to live on a new planet where standard pressure condition is $\pu{2 bar}$, standard concentration is $\pu{1 M},$ and ...
0
votes
2answers
49 views

What is the vapor pressure of a liquid if it is not in a sealed container(i.e., a river or lake)? Is it just the atmospheric pressure? [closed]

From what I understand, the boiling point of a liquid is when its surrounding pressure is equal to its vapor pressure. The vapor pressure is the pressure of the gas form of the liquid in a container ...
0
votes
1answer
62 views

Why is gas pressure measured in mmHg?

Pressure can be measured in $\pu{mmHg}$ which is equal to the pressure exerted by a “column of mercury” of a height expressed in $\pu{mm},$ at $\pu{0 °C}$ under Earth’s normal gravity. Does the ...
0
votes
0answers
11 views

How to compute the pressure potential of the fermentation of sugar into carbon dioxide?

I'm doing an experiment to ferment table sugar with yeast to capture the resulting carbon dioxide. Suppose I put $x$ grams of sugar in a closed 1 liter bottle with yeast. How can I compute the ...
2
votes
1answer
26 views

What actually happens to the volume of a gas in an isolated system?

In an isolated system with adiabatic walls in which gas is filled what exactly happens? How do we define the volume of a gas here? Is volume of 1 mole of gas present in that inelastic container the ...
-1
votes
3answers
66 views

What's the effect of Pressure change in Chemical Equilibrium if any reactant or product is Solid or Liquid?

I am studying La-Chatelier's Principle of Chemical Equilibrium. I got a problem of Pressure change in Chemical Equilibrium. I know that Pressure change If a reversible reaction is in equilibrium ...
-2
votes
2answers
43 views

How do you manage to liquefy a gas by applying only pressure? [closed]

How can you liquefy a gas by applying only pressure? To increase the pressure of a gas you need a compressor, and when the compressor does work on the gas , it will increase his pressure but at the ...
1
vote
1answer
38 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 ...
4
votes
0answers
35 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, ...
1
vote
0answers
72 views

Determining molar mass of protein from osmotic pressure

A 299 mL solution containing 21 g of a protein in toluene had an osmotic pressure of 0.053 atm at 27 degrees Celsius. What is the molar mass (in g/mol) of the protein? We can use the formula that $$\...
3
votes
1answer
116 views

Using osmotic pressure to find the molar mass of a compound

Working on-board a research vessel somewhere at sea, you have (carefully) isolated 12.5 micrograms $(\pu{12.5E-6 g})$ of what you hope is pure saxitoxin (a non-electrolyte) from a poisonous (and quite ...
4
votes
0answers
37 views

membrane for a reverse osmosis desalination experiment

We are second year cram schoolers , we are currently working on a project tackling water desalination by reverse osmosis and are required to do an experience. During the process, we encountered some ...
0
votes
0answers
25 views

how to Find $P_{tot}$ Given that $K_p = 28.5$ and the partial pressure at equilibrium

I have the equilibrium equation : $4KO_2{_{(s)}} + 2CO_2{_{(g)}} \ce{<=>} 2K_2CO_3{_{(s)}} + 3O_2{_{(g)}}~~k_p = 28.5 ~at ~25C$. Given that The partial Pressure of $CO_2$ is $0.191~atm$ at ...
0
votes
0answers
25 views

Finding the partial pressure

So I saw this problem but can't seem to figure out how to get the answer. I got a test tomorrow lol. 41) $\ce{SO2Cl2}$ decomposes in the gas phase by the following reaction: $$\ce{SO2Cl2 -> SO2(g)...
1
vote
0answers
24 views

Impregnating polyethylene with oil using pressure cooker?

I have some polyethylene spiral wrap that I'm hoping to impregnate with citrus oil as an animal deterrent. Wikipedia says that polyethylene plastic will pass through "flavourings" fairly easily. It's ...
5
votes
1answer
129 views

What is the triple point pressure for Gallium?

I have seen various discussions about the triple point of Gallium determined to a very precise value, so precise that it is used as a reference for NIST scales and measurements. However, these ...
0
votes
0answers
11 views

Irreversible isothermal expanison when given final and initial pressure but not external pressure

I'm asking about the second part of the question. So for isothermal, irreversible expansion, w = -Pext *change in volume. I calculated V2 through the fact that p1v1=p2v2 since isothermal. For V2, I ...
4
votes
2answers
118 views

Regarding units of water potential and chemical potential

If water potential is nothing but the chemical potential of a given solution, then why do their units differ? If the unit for the latter is taken as 'Energy per molecule' (which makes sense to me ...
1
vote
0answers
42 views

How to find the final pressure excerted by a mixture of gasses which are then released from a vessel after succesive fillings?

The problem is as follows: $5\ \mathrm l$ of oxygen at $2\ \mathrm{atm}$ of pressure and $10\ \mathrm l$ of nitrogen at $4\ \mathrm{atm}$ are collected in a vessel of $2\ \mathrm l$ in capacity. ...
2
votes
1answer
49 views

Why is so different the temperatures of a compressed gas compared to a liquid/gas mixture of the same fluid and they are both at the same pressure?

Why does $\ce{C3H6}$ gas when compressed (in a centrifugal compressor) comes out with a pressure of $\pu{16 bar}$ and $\pu{90 °C},$ and when it is a mixture of $\ce{C3H6}$ liquid/gas stored inside of ...
3
votes
1answer
202 views

Pressure Vs Volume plot for real and ideal gasses

$$\pmb {\underline {\text {Background}}}$$ 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 ...
0
votes
1answer
32 views

Is the heat for constant pressure the same as for constant volume in the formation of nitric oxide?

In the reaction $\ce{N2 (g) + O2(g) -> 2NO (g)}$ my textbook[1] says $q_v$ and $q_p$ are not the same, without any explanation. I know that \begin{align} \Delta U &= q_p + w\\ \Delta U &=...
2
votes
3answers
135 views

About the use of pascal or atmosphere in chemistry

I was wondering if there are specific formulae in chemistry for which it is "compulsory" or convenient to use atmosphere (atm) rather than pascal (or even mmHg) as a unit of measurement. Of course, ...
0
votes
1answer
34 views

What exactly causes equilibrium to shift when pressure is decreased? [duplicate]

Take the reaction: $$\ce{N2(g) + 3 H2(g) <=> 2 NH3(g)}$$ If pressure is decreased, equilibrium shifts to the left because it has more moles. I understand the basics of why this is, i.e. due to ...
6
votes
0answers
52 views

Using Le Chatelier's Principle to Change Mechanical Energy to Chemical Energy

I was interested in an application of Le Chatelier's principle, where an increase in pressure could result in a decrease in the moles of gas. In particular, a situation where when the pressure ...
2
votes
2answers
339 views

Calculating partial pressure of carbon monoxide

$\ce{ZnO}$ is exposed to pure $\ce{CO}$ at $\pu{1300 K}$ and the equilibrium $$\ce{ZnO(s) + CO(g) <=> Zn(g) + CO2(g)}$$ is then established at $\pu{1 atm}$ pressure. The density of the gas ...
2
votes
1answer
125 views

Vapor pressure vs. ambient pressure

I've managed to get myself thoroughly confused in thinking about the vapor pressure of a substance at a particular temperature $T$, and how it relates to the pressure of the substance if it is in a ...
0
votes
2answers
77 views

Why does reducing the pressure in an equilibrium reaction favour the side with more moles of gas?

I was trying to explain it in terms of reaction rates and such; more than just 'Le Chatelier's principle states ...', but I can't figure out the underlying reason as to why. I can explain why for ...
3
votes
1answer
162 views

Isothermal vs adiabatic compression of an ideal gas [closed]

Could someone please explain these specific questions physically (especially the first question!)? I understand the corresponding mathematical proofs, but not the physical reasoning? I have looked ...
1
vote
2answers
98 views

How to derive this temperature-pressure-specific volume relationship?

(for isentropic, adiabatic, ideal gas flow) $$\frac{T_x}{T_y} = \left(\frac{p_x}{p_y}\right)^{\frac{(\gamma-1)}{\gamma}} = \left(\frac{V_y}{V_x}\right)^{\gamma-1}$$ where $V$ is the specific volume, $...
0
votes
2answers
86 views

Coffee cup lids

So this morning I purchased a coffee. As a not uncommon event the lid on the coffee cup didn't have a hole completely punched through (a gas inflow hole). This makes it difficult to drink the coffee ...
3
votes
1answer
53 views

Stritations in a discharge tube

I am reading about A cathode ray discharge tube and I still do not fully understand why that as you keep on lowering the pressure in the chamber it creates striations, Faraday's dark space and Crooke'...

1
2 3 4 5