If you're seeing this message, it means we're having trouble loading external resources on our website.
If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.
This worked example problem demonstrates how to calculate the energy required to raise the temperature of a sample that includes changes in phase. This problem finds the energy required to turn cold ice into hot steam.
What is the heat in Joules required to convert 25 grams of -10 °C ice into 150 °C steam?Useful information:heat of fusion of water = 334 J/gheat of vaporization of water = 2257 J/gspecific heat of ice = 2.09 J/g·°Cspecific heat of water = 4.18 J/g·°Cspecific heat of steam = 2.09 J/g·°C
The total energy required is the sum of the energy to heat the -10 °C ice to 0 °C ice, melting the 0 °C ice into 0 °C water, heating the water to 100 °C, converting 100 °C water to 100 °C steam and heating the steam to 150 °C. To get the final value, first calculate the individual energy values and then add them up.
Step 1:
Find the heat required to raise the temperature of ice from -10 °C to 0 °C. Use the formula:
q = mcΔT
where
- q = heat energy
- m = mass
- c = specific heat
- ΔT = change in temperature
In this problem:
- q = ?
- m = 25 g
- c = (2.09 J/g·°C
- ΔT = 0 °C - -10 °C (Remember, when you subtract a negative number, it is the same as adding a positive number.)
Plug in the values and solve for q:
q = (25 g)x(2.09 J/g·°C)[(0 °C - -10 °C)]q = (25 g)x(2.09 J/g·°C)x(10 °C)
q = 522.5 J
The heat required to raise the temperature of ice from -10 °C to 0 °C = 522.5 J
Step 2:
Find the heat required to convert 0 °C ice to 0 °C water.
Use the formula for heat:
q = m·ΔHf
where
- q = heat energy
- m = mass
- ΔHf = heat of fusion
For this problem:
- q = ?
- m = 25 g
- ΔHf = 334 J/g
Plugging in the values gives the value for q:
q = (25 g)x(334 J/g)
q = 8350 J
The heat required to convert 0 °C ice to 0 °C water = 8350 J
Step 3:
Find the heat required to raise the temperature of 0 °C water to 100 °C water.q = mcΔTq = (25 g)x(4.18 J/g·°C)[(100 °C - 0 °C)]q = (25 g)x(4.18 J/g·°C)x(100 °C)q = 10450 JThe heat required to raise the temperature of 0 °C water to 100 °C water = 10450 J
Step 4:
Find the heat required to convert 100 °C water to 100 °C steam.
q = m·ΔHvwhere
q = heat energy
m = massΔHv = heat of vaporization
q = (25 g)x(2257 J/g)q = 56425 JThe heat required to convert 100 °C water to 100 °C steam = 56425
Step 5:
Find the heat required to convert 100 °C steam to 150 °C steamq = mcΔTq = (25 g)x(2.09 J/g·°C)[(150 °C - 100 °C)]q = (25 g)x(2.09 J/g·°C)x(50 °C)q = 2612.5 J
The heat required to convert 100 °C steam to 150 °C steam = 2612.5
Step 6:
Find total heat energy. In this final step, put together all of the answers from the previous calculations to cover the entire temperature range.
HeatTotal = HeatStep 1 + HeatStep 2 + HeatStep 3 + HeatStep 4 + HeatStep 5
HeatTotal = 522.5 J + 8350 J + 10450 J + 56425 J + 2612.5 J
HeatTotal = 78360 J
Answer:
The heat required to convert 25 grams of -10 °C ice into 150 °C steam is 78360 J or 78.36 kJ.
- Atkins, Peter and Loretta Jones (2008). Chemical Principles: The Quest for Insight (4th ed.). W. H. Freeman and Company. p. 236. ISBN 0-7167-7355-4.
- Ge, Xinlei; Wang, Xidong (2009). "Calculations of Freezing Point Depression, Boiling Point Elevation, Vapor Pressure and Enthalpies of Vaporization of Electrolyte Solutions by a Modified Three-Characteristic Parameter Correlation Model". Journal of Solution Chemistry. 38 (9): 1097–1117. doi:10.1007/s10953-009-9433-0
- Ott, B.J. Bevan and Juliana Boerio-Goates (2000) Chemical Thermodynamics: Advanced Applications. Academic Press. ISBN 0-12-530985-6.
- Young, Francis W.; Sears, Mark W.; Zemansky, Hugh D. (1982). University Physics (6th ed.). Reading, Mass.: Addison-Wesley. ISBN 978-0-201-07199-3.
As the ice melts the orderly arrangement collapses and the water molecules move past each other and actually get closer together as liquid water. … The motion of the molecules increases enough that it overcomes the attractions the water molecules have for each other causing the ice to melt.
How cold is a glass of ice water?
Originally Answered: What is the temperature of iced water? 32 degrees F 0 degrees C by definition under controlled conditions. This is the temperature where pure water and ice can coexist.
Why do ice cubes melt in the freezer?
The defrost cycle creates heat that passes into the freezer. This heat is absorbed by the ice causing it to melt. After the defrost cycle the freezer cools again. … If the ice bin is full for long periods the ice on top weighs down on the bottom cubes causing them to fuse and clump.
What are properties of ice?
Ice is a unique substance because its solid state — ice — is less dense than its liquid state. Physical properties are characteristics of a substance. They do not change. Physical properties include color smell freezing/melting point and density.
When a piece of ice is placed in water at room temperature the ice melts and water cools down why does their temperature change?
In other words ice absorbs heat from the water. As the water molecules lose energy they begin to slow down and consequently to cool. So it’s kind of the opposite of what we might think: when we put ice in water the ice doesn’t give its cold to the water it takes heat from the water.
When ice melts its temperature decreases or increases?
The temperature of ice remains constant when it starts melting at its melting point. All the heat that is being supplied for the melting ice is used to change the state from solid to liquid while there is no change in the temperature of the ice.
Why do you have to warm the water above room temperature before adding the ice?
As ice melts (at a constant temperature of 0 °C) it forms water at 0 °C absorbing heat energy form the warm water. This cold water then needs to be warmed which absorbs more heat energy form the warm water until a final temperature is reached.
What temperature does ice melt stop working?
At a temperature of 30 degrees (F) one pound of salt (sodium chloride) will melt 46 pounds of ice. But as the temperature drops salt’s effectiveness slows to the point that when you get down near 10 degrees (F) and below salt is barely working.
Does ice melt at 1 degrees Celsius?
Once the air temperature throughout the box is at 0 degrees Celsius all your heat for melting the ice is used up. (Ice melts at 0 degrees Celsius.) … For example both ice and air could end up at -1 degrees Celsius. No ice would have melted.)
Which of the following forms of ice will show the correct melting point of ice?
melting point of ice made from distilled water is 0°C. melting point of any impure liquid is more than pure(original) liquid. hence if the ice is made from sea water( which has impurities) it’s melting point will be more.
What makes ice colder?
Salt makes ice colder because the salt prevents melted water from freezing. Melting is endothermic so it lowers the temperature. Salt helps melt ice and prevent it from re-freezing on sidewalks and roads yet adding salt to ice makes it colder so you can freeze ice cream.
Why does ice get colder with salt?
Because salt lowers the melting point of water if you add salt to ice the ice will melt. … Salty ice water can get much colder than regular water though. While salty 0°F ice will still melt its temperature won’t increase to 32°F like it would in regular water. Instead the salt will turn it into 0°F water.
Can ice be colder than 0 c What is the temperature of an ice water mixture?
And here comes the answer to your question: ice can be colder than 0 °C. It just so happens that the water molecules get packed together tightly at 0 °C (we call this ice) but this doesn’t prohibite it from colding even more because the molecules in ice still vibrate with some velocity.
When ice melts the surrounding air is?
Terms in this set (65) When ice melting energy is absorbed because of this the surrounding air will experience a loss of energy and will be cool. How does melting ice change the temperature of the surrounding air? which the vapor molecules will be more attracted to each other (cohesion) and will become liquid.
Does melting ice give off heat?
As ice melts or liquid water evaporates the molecules change state — from a solid to a liquid from a liquid to a gas or from a solid directly to a gas. … This energy is released when the liquid water subsequently freezes and it is called the latent heat of fusion.
Are there new products formed when ice cube melt?
As an ice cube melts its shape changes as it acquires the ability to flow. However its composition does not change. Melting is an example of a physical change . A physical change is a change to a sample of matter in which some properties of the material change but the identity of the matter does not.
What slows ice melting?
Insulation. General insulation of the ice causes it to melt slower. Wrapping it in wool Styrofoam or wood contains the cold air emitting from the ice keeping the temperature of the ice low. Putting the ice in a vacuum such as a vacuum-insulated Thermos bottle also prevents the ice from melting quickly.