Latent heat Definition and 199 Threads

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...

Homework Statement Here there is another problem from callen which I couldn't finish. It says: It is found that a certain liquid boils at a temperature of 95ºC at the top of a hill, whereas it boils at a temperature of 105º at the bottom. The latent heat is 1000cal/mole. What is the...

Ive got this question but i don't know how to answer it. A steam boiler produces steam at a rate of 0.5 kg.s-1. If the specific latent heat of vaporisation of water is 2.3 MJ kg-1: (a) What power is consumed to achieve this rate? cheers

Homework Statement A thermos contains 160 cm^3 of coffee at 82.7 °C. To cool the coffee, you drop two 10.0-g ice cubes into the thermos. The ice cubes are initially at 0 °C and melt completely. What is the final temperature of the coffee in degrees Celsius? Treat the coffee as if it were...

Hi :smile: The mass of liquid nitrogen in an open beaker is found to have decreased by 46.3 g in 10 minutes. If the s.l.h of vaporisation of nitrogen at its boiling point is 1.99 x 105, at what rate were the surroundings heating the beaker? Why is the heat capacity of the beaker irrelevant...

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...

Hello again my dearest forum <3 I am supposed to learn thermodynamics, but all in all, books here cover only so much of a specific topic. I stumbled upon this term Latent heat. I kinda understand what it is. Its related to phase changes of matter. But is there a quantum background...

Homework Statement Steam at 100°C is injected into 1.8 kg of water at 22°C in a well-insulated container, where it condenses and mixes with the existing water, reaching thermal equilibrium. If the final temperature of the well-mixed water is 25°C, what is the mass of the injected steam...

We did a calorimeter experiment in my school however the teacher warned us that the latent heat of fusion of ice value will be different from the standard value because the ice has water in it and because the ice melts little before actually doing the experiment. However my question is which way...

Homework Statement Find mi, the initial mass of ice. Ti = -20 ci = 2093Jkg-1K-1 Ts = +35 ms = 2kg cs = 837.4Jkg-1K-1 cw = 4187Jkg-1K-1 lf = 3.35x105Jkg-1 S = solid W = water I = ice lf = latent heat of fusion of ice / waterHomework Equations Q=mc\DeltaT Q=C\DeltaT Q=mlThe Attempt at a...

Homework Statement Hi, I've been given the following information to manipulate the results of my last physics practical: Mass Of Water * Specific Heat Capacity of Water * Change in Temperature of Water = Latent Heat of Ice * Mass of Ice + Mass of Ice * Specific Heat Capacity of Water *...

I was looking over an old qualifying exam and I came across a problem asking what the maximum height of a mountain on Earth could be. The solution states that the rock at the base of the mountain will melt and flow away when the potential energy of the top layer of the mountain is equal to the...

An ice-cube has a mass of 7.50 g. The ice-cube is at 0 °C. Heat from the surroundings reaches the ice-cube at an average rate of 1.25 J / s. How long does it take for all of the ice to melt? (specific latent heat of fusion of ice = 333 J / g) A 35.5 s B 55.5 s C 2000 s D 3120 s

Homework Statement 0.5kg of ice at 0 degrees celcius is mixed with 0.1kg of steam at 100 degrees celcius. what will be the final temperature? Homework Equations delta Q= m*c*delta T and at first i thought delta Q= m*Lf ,but then i changed my mind. . . The Attempt at a Solution...

Homework Statement A foundry operator finds that it takes 55.6 MJ of heat to heat a 286 kg mass of an alloy steel from 22 degrees C to 452 degrees C. Specific heat capacity of the steel is 452J/kg/K. If the foundry worker cools the steel by poring water onto it, the water will heat up to its...

Homework Statement A 100g cube of ice at 0 degrees is dropped into 1.0kg of water that was originally at 80 degrees. What is the final temperature of the water after the ice has melted? Homework Equations Q = ml Q = mc(Tf - Ti) The Attempt at a Solution i'm not sure again about...

Hi Everyone :smile: I have to create an experiment for my assignment in Physics. I've chosen to do something about Specific Heat Capacity. A boy in my class is also doing SHC so I wanted to make mine a little different from his. I've just recently joined physics (never done it before)...

I have a couple of questions about this. I know what it is, but need information on specific values. I've been trying to find a table listing as many compounds as possible by their latent heat capacity. I'm also interested in their approximately melting point and would prefer them both in the...

Homework Statement how much energy is required to change a 40g ice cube from ice at -10degrees C to steam at 110degrees C. Homework Equations Q=mL Q=mcT The Attempt at a Solution My failed attempt was this, 0.04*120*333000(333000 is the latent fusion heat for water) i don't know...

Homework Statement (a) An insulated copper container of mass 0.250 kg contains 0.350 kg water. Both the container and the water are initially at 25.0 0C. Then 0.012 kg of ice at 0.0 0C is added to the container. Eventually the container and contents reach thermal equilibrium at 21.7 0C...

Homework Statement 0.1kg of ice was added to a lemonade of mass 330g at an initial temperature of 28 degree celcius and it completely melted. Considering only the lemonade and ice cubes, calculate the final temperature of the lemonade. Given: specific latent heat of fusion of ice= 336000...

a 210 heater is places in 2 kg of water. What temperature rise is produced if the heater is switched on for 200 seconds? I need your help please.

Homework Statement The latent heat of vaporization for water is 540 kcal/kg. By how much does the entropy of 50g of water at 100oC change if the water is very slowly converted into steam at 100oC? Homework Equations The Attempt at a Solution would it be 0 heat change plus the 540...

Homework Statement Heat is added to a 1.0-kg solid sample of a material at 200 °C. The figure shows the temperature of the material as a function of the heat added. http://edugen.wiley.com/edugen/courses/crs1445/art/qb/qu2/c12/r3-1.jpg What is the latent heat of fusion of this material...

Homework Statement Calculate the energy need to change 9 g of ice at -20 degrees Celsius to steam at 110 degrees Celsius. (C for ice=2.06 J/g, C for water=4.18 J/g, C for steam=2.02 J/g, Hf of ice=334 J/g, Hv of water=2260 J/g) Homework Equations Q=hv / Q=mHf / Q=mc(delta)t The...

I asked my teacher this but he did not know so he asked me to find out. When you set fire to something (for example paper) then when it burns all of the heat is released, is this the reason why ashes become cold so quickly?

Homework Statement What quantity of ice at 2 deg Celsius can be melted by 100 J of heat? Homework Equations q = m c (delta) t (mass x specific heat x change in temp) q = m l (mass x heat of fusion) specific heat of ice = 2.09 j/g-K heat of fusion = 6.01 kJ/mol The Attempt...

The following experiment was performed to determine the latent heat of fusion of ice. A 50.0-g aluminum cup was filled with 100 g of warm water. The temperature of the cup and water stabilized at 35C. A 15-g piece of ice at 0C was placed in the water and quickly melted. The final temperature of...

Homework Statement A well-insulated bucket of negligible heat capacity contains 177 g of ice at 0°C. (a) If 20 g of steam at 100°C is injected into the bucket, what is the final equilibrium temperature of the system? I've already solved this part to be 0 degrees Celsius. (b) What...

Homework Statement How much energy is required to change a 46.0 g ice cube from ice at -10.0°C to steam at 116°C? Homework Equations specific heat c = Q/(m(Tf-Ti)) Q = cm(Tf-Ti) latent heat Q = mL The Attempt at a Solution 2.05*10*46+4.1813*100*46+2.080*16*46 +...

Suppose the latent heat of vaporization of H2O were twice its actual value. (a) Other things being equal, would it take the same time, a shorter time, or a longer time for a pot of water on a stove to boil away? (b) Would the evaporative cooling mechanism of the human body be as...

https://www.physicsforums.com/attachment.php?attachmentid=21003&stc=1&d=1255013927 I need help for number 2(b) A student investigates the evaporation of water. He pours 100 cm3 of water into measuring cylinder A and 100 cm3 of water into measuring cylinder B. Measuring cylinder A is kept...

Latent heat of vaporization "Water" thermodynamic -first of all I want to know if the "latent heat of vaporiasation " of water is related to the initial pressure of water ? -If LHV of water is variable with the variation of pressure , how can we calculate the heat needed to vaporise a...

[b]1. Calculate the minimum amount of NRG, in joules required to completely melt 130g of silver initially at 15 degrees Celsius. [b]2. ? Q = mC (Tf-Ti) + mHf? saw it online somewhere, not sure what the proper formula for this problem is, and if it is done does everything need to be converted to...

Homework Statement A quantity of 100g of ice at 0°C and 50g steam at 100°C are added to a container that has 150g water at 30°C. What is the final temp of the container? Ignore the container itself in the calc. Homework Equations Q=mc (change in T) Q=mLThe Attempt at a Solution I know how to...

Can anyone explain that how the ice's temperature is zero degree and water's temperature is 80 degree are mix and their final temperature is zero degree if the both ice and water has the same mass? Where: mc(delta T) of water = (mc(delta T) + mL ) of ice the result for final...

You bought two kilograms of ice at -10 degrees celcius for your cooler when a friend suggests to instead use two kilograms of wood at -10 degrees celsius. Why should you stick with your ice? Thermal Conductivities Latent Heats Specific Heats Answer with either Good Reason, True but Irrelevant...

Homework Statement An insulated cup contains 1kg of water initially at 20 C. 0.50 kg of ice, initially at 0 C is added to the cup of water. The water and ice are allowed to come to thermal equilibrium. The specific heat of ice is 2000 J/kg oC, the specific heat of water 4186 J/kg oC...

Homework Statement Determine the specific latent heat of fusion of ice given the amount of time it takes the ice to melt (150 seconds). Energy is supplied to the ice at 530 W. The sample is .25 kg. Homework Equations Q= ml The Attempt at a Solution (Time * 530W) = .25kg * L 150...

Latent heat calculation! Ok... first timer. I am not a science student, done some MBA but wanting some IT course and for entrance exam, I am preparing. I have problem with this one problem. Just provide me a hint. I do calculation part. 'Juice and water is produced from 5.0 liters of water...

Homework Statement A well insulated cup contains 125 g of water at 23 degrees. How many grams of ice must be added to lower temp to 12? Homework Equations Q = c*m*delta t The Attempt at a Solution energy needed to lower temp: Q = 4190 J / kg * (-11 degrees) * (.125 kg) = -5760 J...

I did a lab experiment were we measured the latent heat of fusion of ice but I am not quite sure what that is. I read that latent heat of fusion is the energy(heat) it takes to change liquid to solid. Is that true? Why would it take heat to freeze something?

Homework Statement The question is: a 6 pack of cola cans contains m grams of liquid. you want to put ice into a perfectly insulated box to cool it down from Ts to Tf. The ice initially has temp Ti. So (a)how much ice would you need as a minimum. (ignore presence of cans and final state of...

[b]1. I need to find the latent heat of fusion of ice. The problem scenario is that i have a cup and fill it 1/3 full with water. I then take a cube of ice and put it in the cup. then the cube of ice melts mass of the cup=.24g mass of the cup when filled 1/3 with water=71.16g initial...

Homework Statement When spring finally arrives in the mountains, the snow pack may be two meters deep, composed of 50 % ice and 50 % air. Direct sunlight provides about 1000 wats /m^2 to Earth's surface, but the snow might reflect 90 % of this energy. Estimate how many weeks the snow pack...

We could use the change of entropy before and after eh phase changed to calculate the latent heat L = (S_{after} - S_{before})T and in some case, if we know the relation of pressure and temperature, we can also apply Clausius-Clapeyron relation to calculate the latent heat. I...

Homework Statement Several small piece of aluminum, having total (combined) mass of 2.5 kg are placed in liquid nitrogen and, when removed, are at a temperature of -135C. The aluminum is transferred to an insulating container with 0.50 kg of water. The water is at 25.0C [ Ignore heat lost from...

Homework Statement see attachment Homework Equations The Attempt at a Solution I think I would divide the approximate slope from the beggining by the approximate slope at the end but I'm not sure if that is correct. Also, I do not know how to come up with a number answer.

I have a derived equation for latent heat, L = kIV∆T/∆M. I was just wondering what the value for k is. I have it written down in my notebook but i can't tell if i wrote a 2 or a 7, so it should be .239 or .739. If anyone knows it'd be appreciated, thanks.

Homework Statement An ice tray containing 200 g of water at 25 degrees celecius is placed in the freezer. How much heat energy has to be removed to change the water into ice at -4 degrees celcius? Homework Equations Q= mc(Tf-Ti) + MLf + mc(Tf-Ti) The Attempt at a Solution I know...