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FC S3W3 Change of phase

Last updated 3 months ago
31 questions
1

Transfer of heat through a fluid or gas is called?

1

Transfer of heat through electromagnetic waves is called?

1

Material that reduces the transfer of heat is called?

1

How is heat transferred in a convection current?

1

Read Chapter 16. Do you have any questions?

1

what are the four common phases of matter?

1

What happens during a change of phase?

1

Which statement is true about latent heat?

1

Why will water at the bottom of a geyser not boil even though it is at 100° C?

1

Why is the boiling point of water lower at higher altitudes?

1

under the right conditions, something could boil and freeze at the same time.

1

What is regelation?

1

the boiling point of water is always 100°C

1

The temperature and pressure at which liquid water, ice and steam coexist is called the

1

How does pressure affect the boiling point and melting point of water?

1

A couple weeks ago, we calculated the amount of 0°C water I would need to cool my daughter's axolotl tank 5°C (from 25° to 20°). we determined that I would need to transfer 20kg x 42000J/kg°C x 5°C = 420000 J of energy away from the water. we did this with 5 liters of 0° water because 5kg x 42000j/kg°C x 20°C comes out to the same amount of heat to heat the water from 0°to 20°o calculate this if the water was frozen at 0°C adds another step. The equation you need is


where Q is the amount of heat required to change an object of mass m from frozen to liquid, and L_f is the latent heat of fusion, which is 334,000J J/kg for water. Now I am using the equation


using this equation, solve for m

1

to calculate the amount of heat needed to boil water the equation is Q=mL_v, where L_v is the latent heat of vaporization. The latent heat of vaporization of water is 2260 kJ/kg . Does this mean it takes more energy to melt ice or boil water?

1

If you boil water, you are constantly adding heat to the system, but as the water boils, the temperature of the water remains constant at 100°C (assuming you are close to sea level). Where does the extra heat go?

1

child A has wet hands, and child B does not. Both decide to briefly touch their mother's iron. One is burned, but the other is not. who is not burned and why?

1

What does it mean that boiling and evaporation is a cooling action?

1

If you have a convenient kitchen thermometer, go boil a couple cups of water. take the temperature of the water as it boils. Then put two tablespoons of salt into the water, and bring back to a boil. measure the temperature now. what do you observe. If you don't have a convenient kitchen thermometer, call a friend from class, and see if you can watch that person do this.

For the next several questions we are working with the following problem: you have an insulated vessel with 100g of steam at 100°C. You drop a block of 1000g of ice at 0°C into the vessel (with not transfer to the outside world (airlock, cleanroom, whatever. Ideal physics-land transfer.) Heres what you will need to know.

L_v of water = 2260 J/g
L_f of water =334 J/g
The specific heat capacity of water =42 J/g°C
1

without calculations, guess which of the following will happen.

1

Does the steam condensing into water absorb heat or release heat?

1

Does the ice melting into water absorb heat or release heat?

1

Using Q=mL_v calculate the amount of latent heat in the steam.

1

Using Q=mL_f calculate the amount of latent heat needed to melt all the ice.

1

Assume all the latent heat released from one is absorbed by the other. If they were the exact same number, we could assume that all the steam condensed and all the ice melted, and then we could consider what would happen if we mixed 100g of water at 0°C with 1000g of water at 1000°C. Can we do that?

1

Hint, the answer above is NOT "yes". You have two answers from questions 21 and 22. Subtract the smaller number from the bigger number, what do you get?

1

Given this, revisit your prediction in question 18. What do you think happened in this situation? what are you left with? Honors - think through what you think you would need to do to calculate the exact amount of ice/steam left as ice/steam, if any, and the end temperature of the water in the system?

1

what would you need to know if you were to do the same question, with the exception that the ice started at a temperature below 0°C and the steam started above 100°C?

1

concept categorization

  • what a phase of matter is
  • what latent heat is
  • why a substance stays at the same temperature when changing phase
  • how to calculate latent heat
  • how to know if changing phase absorbs or releases energy
  • what causes regelation
  • the relationship between pressure, temperature and boiling point
  • triple point
  • critical point
  • I got this
  • im shaky
  • so confused