Vaporization Definition and 80 Threads

According to the Vaporization Heat table, the heat needed for 1 mol of H2O to evaporate at 100°C is 40.7KJ and 44.0KJ/mol is needed to evaporate H2O at 25°C. Thus 44.0-40.7=3.7KJ is the energy needed to heat H2O to 100°C from 25°C. However, according to the heat capacity of H2O, 3.7KJ will only...

answer is 78oCdelta G = delta H - T delta S -235,310- (-277,690) = -38.56e3- T (282.59-160.70) T = -664K I am not sure if my concept is correct. May anyone help a little bit on that please? thank you

I am trying to calculate the increase in pressure caused by liquid nitrogen when it changes from liquid to vapor within a closed, constant volume at atmospheric pressure. How can this be done? Do I need to include the heat of vaporization?

Hello everyone, before I start I just want to mention that I am not an expert in physics whatsoever, so please be as specific as you can get if you wish to provide an answer. (The question itself might be considered stupid to be honest) I read the definition of the boiling point recently and...

Hello everyone ! I am currently looking for a way to find the heat of vaporization of Acrylonitrile butadiene styrene I can not find any papers or source about it, so maybe I thought there is some chemistery table that could help ? Do you have any ideas/sources ? Thank you !

After completing an experiment observing a glass of water on a switched-on cooker with an infrared camera, some water drops accidentally landed on the surface of the hot cooker and started to bounce from one point to another until they finally vaporized. I wonder why the drops instead of...

Hi, All. Given a scenario of a closed volume of volatile liquid and it's associated vapor above boiling point (ex. butane in a can at room temp.) which is dispensed through some tube or line: Is there some filtering medium capable of ensuring that only vapor may pass through the line, producing...

Homework Statement A 0.035 kg ice cube at its melting point is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of -196 C? Nitrogen has heat of vaporization of 200000 J/kg Ice's specific heat is 2100 J/kg*C Homework Equations...

According to the first law of thermodynamics, dQ = dU + dW and you can find dU = nCvdT If this is the case then when water at 100°C vaporizes to steam at 100°C shouldn't the change in internal energy be zero because it is dependent on temperature change?

Homework Statement During the game, the metabolism of basketball players often increases by as much as 30.0 W. How much perspiration must a player vaporize per hour to dissipate this extra thermal energy? Assume that perspiration is simply pure water and that perspiration starts at temperature...

I believe my attempt below is correct but I'm not 100% sure, any guidance welcome. 1. Homework Statement Suppose a meteor of volume 1000 km3, density 5000 kg m-3 and speed 30000 km hr-1 crashed into the ocean and 10% of the impact energy was converted directly into heat. i) Estimate the...

My question is harder to explain than I would imagine it will be to answer. I'm trying to vaporize a non-combustible fuel source with an internal radiant coil surrounding a small vaporization chamber consisting of a heat-resistant cotton-like material being fueled by a constant drip fuel pump...

Homework Statement If I have a pot of water that I want to bowl so that there won't be any water left then the energy that I have to add is: E=c*m*delta T E=l(vaporization) * m But if I have wet clothes and want the water to evaporate then the energy needed is: E=l(vaporization)m So from...

Hi Everyone, I'm currently developing a waste heat recovery device as a side project. The system I've created uses a solution of acetone and water. One step in the process involves vaporizing acetone from the water at a low grade heat temperature (note: acetone does not form an azeotrope with...

I understand that the lattice energy is the energy released when an solid ionic compound forms or it is the energy required to separate completely a mole of a solid ionic compound into its gaseous ions. So is second definition the same thing as vaporizing an ionic compound and so we can...

Hello friends, The balanced chemical equation for the combustion of carbon is: C(solid) + O2(gas) -> CO2(gas) Now, the lower and higher heating value of hydrocarbon fuels (such as methane) exists because in the LOWER heating value, you are subtracting away the latent heat of vaporization of...

The Wikipedia page on the heat of vaporization has a nice graph showing the heat of vaporization going to zero at the critical points of various substances. Is there a known form for the heat of vaporization as a function of temperature near the critical point? I imagine it is probably a power...

Homework Statement How many kilocalories of heat are needed to change 143N of ethyl alcohol at 65°C to vapour? Homework Equations Lv = Q/m The Attempt at a Solution I'm really stuck. I have no idea how to work the units of N with heat problems. I've looked online and in my book and have no...

In modern nanotechnologies, metals can be vapourized to coat onto the surface of another material as a thin but hard protective layer. How much energy would it take to heat 0.55 kg of iron from 1400oC to vapour at 2050oC?

1. One gram of water occupies a volume of 1 cm3 at atmospheric pressure. When this amount of water is boiled, it becomes 1671 cm3 of steam. Calculate the change in internal energy for this vaporization process. The heat of vaporization for water is 2.26 x 106 J/kg. 2. w = -PΔV, E = q + w...

When I'm doing the Physics homework the problem for heat of vaporization uses Q=mcΔT and Q=mLv. How do I know when to use which equation through out the problem?

Homework Statement Internal Energy Change Homework Equations N/A The Attempt at a Solution If internal energy change equals enthalpy change, then I am looking for the reaction which has the enthalpy change closest to zero. I know it cannot be A, as the formation of water is highly exothermic...

I am trying to give some context to medical vaporizers in a literature review I am composing and initially decided to give asthma inhalers and nasal inhalers as examples. I realized however, that some sources on-line were referring to these metered dose inhalers as vaporization devices when...

A normal behavior of a plastic jerry can used for gasoline is that it expands by the pressure caused by vaporization of the gas. Which option below will be the best alternative to reduce the pressure caused by vaporization in a jerry can during storage? : - Fill up the can as much as possible...

Homework Statement The normal boiling point of hexane is 69.0°C. Estimate (a) its enthalpy of vaporization The Attempt at a Solution In order to solve for ΔHvap in the Clausius-Clapeyron equation I need a reference T and p point. I extracted it from the triple point (T=178K and p=1,23Pa)...

Heat of vaporization of water slightly decreases with temperature. https://en.wikipedia.org/wiki/Enthalpy_of_vaporization Does anybody know of a simple explanation of this fact based on molecular theory? Or any explanation whatsoever. The Wikipedia article says " The heat of...

Homework Statement What is the vapor pressure of benzene at 50.0 C? Benzene's boiling point is 80.1 C and its heat of vaporization is 31 kJ/mol Homework Equations The Attempt at a Solution I don't want to be that guy who just says "I don't know" but.. All I know is that: ln P...

I've curious about how an air conditioner or refrigerator make's cold air. I've read two different descriptions how cold is "made", or how heat is removed from a system. Some descriptions I've read say that air conditioners use expanding gas in it's coils, hence the use of Boyle's law. Other...

Hi everyone. I am having a problem that hopefully someone here can help me with. For the purposes of flash calculations, I’m trying to find the enthalpy of vaporization of a compound using the Antoine equation and Clapeyron equation. I am using heptane at 15.5597 psia as an example. For the...

Using line equation y = -4058.7x + 16.10 with the experiment pressure measured in kPa instead of atm. I already solved for heat of vaporization thus: (-4058.7K)(-8.314 J/mol \astK)=heat of vaporization = 33444 J/mol = 33.44 kJ/mol. Also, the vapor pressure for normal boiling point...

Homework Statement Given the attached figure, a) Develop an ordinary differential equation that describes the dynamic height h(t) in the flash tank in terms of \dot{m}_{i}, \dot{m}_{l},\dot{m}_{v}, \rho_{i}, \rho_{l}, \rho_{v}, and A. b) Given the fact that the process is isenthalpic...

one mole of liquid water (100 deg C, vapor pressure = 1 atm) in a container is introduced into an evacuated vessel maintained at 100 deg C and allowed to evaporated. The volume of the vessel is such that the final pressure of the gaseous water is 0.1 atm. Given the (normal) latent heat of 9,730...

Hello, I recall watching a show that discussed several personal flying devise the military had invented over the years. One of them was the Hiller's flying platform, but there was another that they mentioned. It was a jet pack of sorts (I can't recall it's name) and it used steam. I don't...

Homework Statement The latent heat of vaporization of a substance is defined as the amount of heat required to transform the substance from its liquid into its vapor phase. A certain material has a boiling point of 700K and its molecules have three degrees of freedom in the liquid phase but...

Homework Statement Hi, I am answering Question #3, and using the formula and variables above scratch area as reference on how to answer the question. Could someone please have a look and see if the problem I worked out came out correct. Homework Equations The Attempt at a Solution First I...

How is it possible to completely vaporize a mixture at constant temperature? I have seen listed values for ΔH(Vaporization); however, this doesn't quite make sense to me. If a mixture (with two largely diffent boiling points) is at its boiling point in the liquid state and I want to completely...

Homework Equations d ln(Psat) / d (1/T) = -ΔHvap/R (Clausius-Clapeyron) The Attempt at a Solution When solving for the enthalpy of vaporization using the Clausius-Clapeyron equation, is the resulting value an average over the temperature range? I assume this is the case, because...

I am having confusion with the difference between these two, or are they synonymous terms?

Hey guys, I was just hoping to clear something up regarding enthalpies of vaporization. The idea of the heat of vaporization for a substance being "temperature dependent" is confusing me, as I had been under the impression that these quantities were only considered at the boiling point of...

A student suspects that the power rating on an immersion heater is 50 W but he is not sure.He sets up an apparatus as shown. After the liquid has been brought to its boiling point, he finds that 3.5g of vapor escaped each minute through the outlet tube.The boiling point of the liquid is 80...

Doing some fun problems in Keith Stowe's 'An Introduction to Thermodynamics and Statistical Mechanics'. Good book. Problem statement: A certain material vaporizes from the liquid phase at 700 K. In both phases, the molecules have three degrees of freedom. If u_{0} in the liquid phase is...

Why is the latent heat of vaporisation greater than that of fusion(melting)? I mean in liquid state,atoms are already far apart, so it must require less energy to make them gas(far apart) as forces(electric in nature) between molecules decrease with distance.

Hi, I would like to ask, why is it that the specific latent heat of vaporization of water at, say 10 degrees Celsius, is considerably higher that at 100 degrees Celsius? It would be great if you could provide an explanation from the molecular view. Thanks.

This is a question from a quiz in my physical chemistry class For 1 mole of H20, calculate \Delta{S_{sys}}, \Delta{S_{surr}}, \Delta{S_{univ}}, and \Delta{G_{sys}} for the following transition at 1 atm pressure and 95 degrees Celcius H20 (l) ---------> H20 (g) Right now, what I'm confused...

I'm making my way through some workbooks at my job (coal-fired power plant) and I've hit a stumbling block. I could just memorize what the books says, but I really want to understand, so here goes... One question states: "As the pressure exerted on a steam/water mixture increases, (answer...

Hi, When studying and thinking about the concept of Specific Latent Heat of Vaporization I keep falling in the trap of confusing it with evaporation - in the end, in both cases water in the liquid state is being changed into vapor. Could anyone help me differentiate the two ideas...

I'm trying to understanding "Heat of Vaporization" in fundamental terms. People say that processes like evaporation and boiling are endothermic because chemical bonds are being broken, but for actual cooling to occur there must a loss in translational kinetic energy of the molecules involved...

Homework Statement Using the following vapor pressure data solve for the heat of vaporization for substance x. T VP 20 100 30 175 40 325 Homework Equations ln (P1/P2) = -Heat of vap/RT (1/T2 - 1/T1) The Attempt at a Solution I know the answer is...

Homework Statement A new liquid is discovered that has the same boiling point and specific heat as water but a latent heat of vaporization of 10 calories per gram. Assuming that this new liquid is safe to drink, would it be more or less convient than water for boiling eggs? Why? The...

Hi to all...i've a problem. i have to calculate the position and the time of complete evaporation of a continuous water flow which is injected trough a nozzle into a continuous flow of steam in superheated condition. The position (and than the time) at which I'm sure that there aren't water...