Liquid Definition and 1000 Threads

A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, and plasma), and is the only state with a definite volume but no fixed shape. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds. Like a gas, a liquid is able to flow and take the shape of a container. Most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly constant density. A distinctive property of the liquid state is surface tension, leading to wetting phenomena. Water is, by far, the most common liquid on Earth.
The density of a liquid is usually close to that of a solid, and much higher than in a gas. Therefore, liquid and solid are both termed condensed matter. On the other hand, as liquids and gases share the ability to flow, they are both called fluids. Although liquid water is abundant on Earth, this state of matter is actually the least common in the known universe, because liquids require a relatively narrow temperature/pressure range to exist. Most known matter in the universe is in gaseous form (with traces of detectable solid matter) as interstellar clouds or in plasma from within stars.

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  1. B

    What Cheap Liquid Can Harden to Fill 3D Printed Models?

    I'm looking for a cheap material that I can fill plastic hollow model's with, that will harden up, to give the model a good weight. The model's are being made by a 3D Printer, and if made hollow, they don't weight a whole lot. Any suggestions?
  2. S

    In the haber process why is the yield higher when liquid?

    I know that setting the conditions so that the product is formed as a liquid will produce a higher yield in the manufacture of Ammonia, but why is this?
  3. L

    Liquid helium - Siemens-cycle only?

    Why can't I reach 4K with the Siemens-cycle?
  4. R

    What are the properties of ferromagnetic powder?

    Hello! I am trying to understand a few properties of the ferromagnetic powder.I could not get the answers to these questions on the web, since any kind of phrasing i used, popped up search results that related to iron powder or ferromagnetic powder, which are manipulated and shape-shift using...
  5. R

    Making a 50% solution from Liquid Citric Acid

    I have a bottle of !00% liquid Citric Acid with the label showing Citric Acid and Water as contents. I need a 50% solution of the acid. Do I dilute this with water 50-50?
  6. snowwhite

    Thermo question -- volumetric flows of dry steam and liquid water

    1. Homework Statement Given the rate of pipe= 100 kg/s The steam flow has quality x= 80% = 0.8, pressure= 90 atm Find the volumetric flows of dry steam and liquid water 2. Relevant equations...
  7. L

    Bubble in Liquid: Phase Change Under Pressure?

    Anyone , what the bubble in the fluid will be if we compressed the fluid with high pressure? for example the fluid is oil with high viscous. does the bubble change in phase? (condense)
  8. C

    Determining the amount of liquid water in a pressure vessel

    So there is a mass of 100kg and volume of 1m^3. (Distiller water) That's 0.01 m^3/kg How do I calculate the percentages?
  9. M

    Conceptual Heat X-fer Question (Steady state, liquid changing temp as it flows)

    Homework Statement Not hw.. My teacher wants us to understand this as it is important for reactor design. A liquid is flowing through a tube of diameter D. The inner wall of the tube is maintained at a constant temperature of Ts. The liquid enters at a temperature of Tw1and leaves at a...
  10. K

    Exam question that I have no idea how to solve (regarding forces and mass)

    1. The problem statement Peter threw 10 (same) coins into an empty container (a tube/drum), which was floating in A LIQUID. The diameter of the container was 2,257 cm, and so because the container is a tube the surface of the tube was equal to π times the diameter squared. He measured, after 4...
  11. M

    Valve that allows the flow of liquid but prevent air escaping

    Hello, I do not really know if this is the right place to post this message ... if it's not then I'm sorry I am looking for a valve that allows the flow of liquid but prevent air escaping out form let's say a sealed container ... Is there such a thing?
  12. C

    Energy released by condensing steam back to liquid water

    Homework Statement vaporized 19 kg of water and did not capture and condense it. It took 42.9 MJ to vaporize the water, how much energy did I lose from not condensing the steam? Homework Equations Latent Heat of Water = 2260kJ/kg The Attempt at a Solution Would the energy lost to not...
  13. S

    Changes in volume of a liquid affects?

    I have say a 250cm3 liquid with a solid dissolved inside filled in a container. If I pour 50cm^3 of that liquid in another container, would the number of moles of the solid inside the 50cm^3 container be different to the number of moles in the original 250cm^3 container? I've been told the...
  14. W

    Does Atmospheric Pressure or Temperature Determine the State of CO2?

    Let's say you have a 20 bar atmosphere of 95% nitrogen, 3% oxygen, 1% argon and 1% Co2 cooled to 0 F. Would Co2 be liquid or gas?
  15. S

    The Case of Electronic structure of Liquid Metals

    I have been contemplating for a few days now about how one could think about the electronic structure of Liquid metals. The cases of an isolated atom or that of solid metal crystal are well known and easy to understand. Though, a google search reveals (to me) that nothing much has come out for...
  16. M

    Which Liquid Would Form the Densest Vapor Upon Heating?

    Homework Statement Which of the following liquids would form the densest vapor upon heating? A. CH3CH2CH2OH B .CH3(CH2)3CH2Cl C. CH3(CH2)4CH2Br D. (CH3)3CCH2OH Homework Equations None really The Attempt at a Solution Now I know the answer already, its C. My question is why? I got B, my...
  17. J

    Fluids with high expansion ratios that do not leave the liquid state

    Hey guys, I've been doing a lot of research looking for a fluid that has a high expansion ratio that does not leave the liquid state. the idea is that the fluid could either: - using heat will expand and contract using hot and cold cycles - using electricity (not necessarily needing...
  18. A

    Specific heat capacity of liquid form of permanent gases.

    Hi, The permanent gases like Nitrogen, Helium etc. have more specific heat capacity as liquid than their gases. Seemingly degree of freedom should reduce in liquid form, and therefore, specific heat capacity must reduce in liquid form. But this isn't the case. I remember reading somewhere...
  19. M

    Getting a Sanity Check on Calculating Combined Density of Gas & Liquid Flow

    Hello, Long time lurker, 1st time poster. I need a sanity check that I am solving this problem correctly. I have a pipe with a combination of gas and liquid flowing through it, the density of the gas (ρg) is 5.5kg/m^3, the density of the liquid (ρL) is 435 kg/m^3. I have a vapor...
  20. M

    Volume Change in Phase Transitions

    Homework Statement It's not so much an exact question. One of the things I need to figure out to answer my question is if there is a formula of some sort that helps me calculate volume change through a phase change. The final volume of a liquid that vaporizes into a gas, if the temperature and...
  21. C

    Gas or liquid which can push piston

    Greetings .! This is regarding a lab experiment .I need to find out if we can boil or heat a liquid ,which is connected by with a manometer and a piston .We need to push the piston and also see the reading in the manometer. Which is the ideal liquid or gas , which will not eak or hold on to...
  22. B

    Direct Heat Transfer Between a Liquid And a Gas

    Hey guys, I was trying to find the answer to this question but could not seem to find anything. I am trying to figure out how to calculate heat transfer rate between a liquid and a gas. Say the the liquid is water in a chamber (with no heat transfer to the walls). The gas is the residual...
  23. B

    Dropping Balls in tube with liquid

    Homework Statement So, I am having trouble trying to understand my results. The experiment was marble (1.5cm & 5gram) was dropped on the surface of water, in a 40 cm cylindrical tube roughly 4cm diameter. The graph is negative, since the I used a program to analyse the velocity. Homework...
  24. AllenJH

    Displacement energy of atom in a liquid (for ion implantation)

    Hi Physics Forums! I'm a bit stuck here. I'm fairly sure I intuitively know the answer here, but am looking for harder proof. The following question is in regards to my current research work (materials sci/eng). Does anyone know of a discussion of the displacement energy of an atom in a...
  25. A

    Liquid Metal Under Applied Voltage

    Hi guys! I have a question regarding liquid metals. Suppose you had a droplet of liquid metal in empty space. Take the droplet and connect it to a DC source. What happens if the voltage of the DC source exceeds the surface tension of the liquid metal droplet? Would the droplet split in two...
  26. K

    Get rid of transuranians in Liquid Fluoride Thorium Reactors?

    Liquid Fluoride Thorium Reactors might be a fantastic source of energy for the future. It looks like the world is divided into two clans and the moment: those who have heard of LFTR and are enthusiastic, and those who have hardly ever heard of it because it is hardly mentioned even in the most...
  27. S

    Why is Buoyancy Force = to the density of the liquid * Vobj(submerg)*g

    Why is the weight of the liquid displaced = buoyancy force and not the weight of the submerged volume of the object? Does it have something to do with normal force of the surface of the liquid on the object or pressure?
  28. L

    Air Pressure vs Liquid Pressure

    Okay, so I am looking at this article (link at bottom) and it says they have a microorganism liquid contained inside of a CLOSED steel pipe fitting and they heat it until it's reached about 570 degrees inside. SO HOW MUCH PRESSURE GROWS INSIDE THE CLOSED CONTAINER? As far as a real life...
  29. L

    Boiling liquid in a sealed container

    Suppose I have a sealed container of fixed volume containing 3/4 air and 1/4 of some liquid by volume at room temperature (22C). I wish to boil the liquid by applying external heat. As I apply heat to the container, the pressure inside the container will rise, which will change the boiling...
  30. marellasunny

    Is the condenser of a E-vehicle cooled by liquid circulation?

    I've noticed that a FEW of the electrical vehicles have no front grill. I am quite surprised that they do not have one, because the condenser of the AC unit needs to have heat taken away from it (in other words, the condenser needs a heat exchanger). So, in view of the fact that E-vehicles don't...
  31. R

    Is it possible for liquid hydrogen to exist in space?

    Hi, I was wondering why there is no liquid hydrogen in space? Space is very cold, more cold then the temperature that is required to convert gas hydrogen to liquid here on earth? Therefore, why is hydrogen in space in gas form and not liquid? Thanks
  32. E

    Focal length of converging meniscus lens filled with a liquid

    Homework Statement A converging meniscus lens is made of glass with index of refraction n = 1.55, and its sides have radii of curvature of 4.5 cm and 9 cm. The concave surface is placed upward and filled with carbon tetrachloride which has index of refraction n' = 1.46. Determine the focal...
  33. D

    Is the Answer Correct? Dipping a Cylinder w/ Small Hole in Liquid

    An empty cylindrical vessel with a small circular hole of radius r at the bottom is dipped vertically in a liquid of density d keeping the bottom downward. At what maximum depth can it be dipped before the liquid enters into it? The surface tension of the liquid is S. The answer given in the...
  34. Warpspeed13

    Practical question liquid nitrogen stump removal

    Ok so I need to get a 3foot stump out of concrete without damaging the concrete. It's at that terrible stage where it's to rotten to pull out and to solid to scoop out. My idea is to drill a hole and pour liquid nitrogen down the hole to make the wood brittle and then smash it with a pry bar...
  35. S

    Variation in tube wall temperature as steam condenses to form liquid

    I'm having a bit of difficulty conceptually understanding a problem. Hoping someone here can clear it up for me. In a simple circular condenser tube (which is cooled by water or air) what happens the tube wall temperature as the steam inside is condensed? Intuitively I would have thought that...
  36. C

    Questions Regarding Homemade Liquid Fuel Engine

    For the last six or so months I've recaptured my childhood love of rockets (I'm now in college), and have spent a great deal of time both reacquainting myself with the basic information and also learning more about the engineering and technical side of them (now that I've learned things like...
  37. R

    Pressure on a liquid semisphere

    Imagine to have a drop of water(semisphere volume) on a flat membrane covered by a polymer so that the liquid can't excape from this envelope. If I apply a pressure upon this sphere (imagine a plane at a constant pressure that step by step would squeeze down the central part of the semisphere...
  38. Artlav

    What can be used to measure liquid nitrogen temperature?

    Hi. I'm looking for a common electronic component that can be used to determine a temperature between room temperature and that of liquid nitrogen. -Multimetre probe failed, getting stuck at -135*C -Common NTC thermistors rapidly ascent past gigaohm range, even from 1Ω-5Ω initial values...
  39. W

    Completely dissolving a gas into a liquid

    Hello PF I want to dissolve a gas in a liquid. I figured I could create a closed loop vacuum system. I introduce gas into the lines at atmospheric pressure, and then close off the lines, so the intake and exhaust of the vacuum pump are connected. Then I turn the pump on and the gas just...
  40. V

    Oscillation of a liquid in U -tube

    I am facing difficulty in understanding a key point . Hence I am putting it here instead of Introductory Physics section . Here is a part of the solution provided by the teacher ,but it doesn't look convincing to me. Similar solution is provided here...
  41. S

    Temperature Rise due to Increase in Pressure (Liquid)

    I need help finding the temperature rise of a liquid (specifically diesel) due to a pressure increase. The system contains a pump at 500 hp and runs at 524 gpm. The inlet temperature is 75 F and the pressure is 150 psi. The exit pressure is about 1155 psi. I have the specific gravity as 0.841...
  42. U

    Liquid, superheated vapour and a mixture

    Homework Statement how do i determine whether water is at liquid, superheated vapour r a mixture state?? Homework Equations The Attempt at a Solution
  43. O

    Diffusion of Liquid: Explaining the Physics

    Hello. I know what is diffusion... chemical process when molecules from a material move from an area of high concentration to an area of low concentration... Typical example is ink in water. However, how it works? Molecules of water collide with molecules of ink? How it is happens from the...
  44. O

    Molecular Physics: Why is Less Dense Liquid Higher Than More Dense?

    Please, tell me really simply from the viewpoint of molecular physics... Why is liquid having a smaller density on liquid having a bigger density? Thanks
  45. L

    Liquid - polymer equilibrium "contact" distance

    Hi everyone, In this paper ( http://pubs.acs.org/doi/abs/10.1021/la962131c ), the authors calculate the surface energy of polymer and the contact angle of various liquids on these polymers using a so-called "liquid - polymer equilbrium contact dsitance". I'm wondering how to calculate such a...
  46. A

    Understanding pressure in a liquid

    I've always found pressure fairly intuitive to understand when dealing with ideal gases, but am struggling a little with a thought experiment concerning pressure changes in a liquid. Here's a simple thought experiment I'm struggling with. I'm thinking of a still volume of pure water at...
  47. H

    How does this make mercury a liquid at STP?

    Thinking back to my undergraduate years in Chemistry 101, it always struck me as strange that mercury, a transition metal, was liquid at room temperature. When I asked the professor about it, he said the explanation was by no means simple and involved both the electronic configuration of mercury...
  48. I

    Liquid nitrogen generator, N2 gas generator

    I thought some of you engineers would be interested in reading my web tutorials. I have written some extensive tutorials on the theory and building of a homemade N2 gas generator. It takes regular air, and using pressure swing adsorption, concentrates the N2 up to 99%. This is here. I then...
  49. P

    The specific heat capacity at constant volume for liquid isopropanol?

    Hey I am a physics student, and not so familiar with chemistry. I have a huge problem, because I have to find the following 3 values for liquid isopropanol: 1. The specific heat capacity at constant volume 2. The specific heat capacity at constant pressure 3. Volumetric Isobaric...
  50. D

    Standard entropy of a liquid at melting temperature

    I am presented a review of data which gives: vapour pressures of a liquid have been measured and fit to the following equation: Log10 (mmHg) = -3571/T + 8.999 The melting point has been determined to be 392.7 K. A Cp value given for the liquid is 250 J/mol K and the ΔSvap is 117 J/mol K...
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