FC S3W3 Change of phase

Last updated 9 months ago

31 questions

1

Library

FC S3W3 Change of phase

Last updated 9 months ago

31 questions

1

Read Chapter 16. Do you have any questions?

1

what are the four common phases of matter?

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

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

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.

1

Transfer of heat through a fluid or gas is called?

Insulation

Radiation

Convection

Conduction

Transfer of heat through electromagnetic waves is called?

Conduction

Insulation

Radiation

Convection

Material that reduces the transfer of heat is called?

Radiation

Convection

Insulation

Conduction

How is heat transferred in a convection current?

Through the movement of fluids

Through the collision of particles

Through direct contact with objects

Through electromagnetic waves

Read Chapter 16. Do you have any questions?

what are the four common phases of matter?

What happens during a change of phase?

Temperature fluctuates

Temperature decreases

Temperature remains constant

Temperature increases

Which statement is true about latent heat?

It is only released during a change from gas to liquid

It increases the temperature of a substance

It only exists in liquid phase

It is released or absorbed during a change of phase

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

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

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

True

False

What is regelation?

The phenomenon of melting under pressure

The phenomenon of melting due to change in temperature

The phenomenon of solidifying due to change in temperature

The phenomenon of solidifying under pressure

the boiling point of water is always 100°C

True

False

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

sublimation zone

That is not a thing.

triple point

critical point

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

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

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?

more to boil water than melt ice

less to boil water than melt ice

same for both

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?

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?

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

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.

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

Transfer of heat through a fluid or gas is called?

Insulation

Radiation

Convection

Conduction

Transfer of heat through electromagnetic waves is called?

Conduction

Insulation

Radiation

Convection

Material that reduces the transfer of heat is called?

Radiation

Convection

Insulation

Conduction

How is heat transferred in a convection current?

Through the movement of fluids

Through the collision of particles

Through direct contact with objects

Through electromagnetic waves

What happens during a change of phase?

Temperature fluctuates

Temperature decreases

Temperature remains constant

Temperature increases

Which statement is true about latent heat?

It is only released during a change from gas to liquid

It increases the temperature of a substance

It only exists in liquid phase

It is released or absorbed during a change of phase

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

True

False

What is regelation?

The phenomenon of melting under pressure

The phenomenon of melting due to change in temperature

The phenomenon of solidifying due to change in temperature

The phenomenon of solidifying under pressure

the boiling point of water is always 100°C

True

False

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

sublimation zone

That is not a thing.

triple point

critical point

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?

more to boil water than melt ice

less to boil water than melt ice

same for both

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

without calculations, guess which of the following will happen.

All the ice will melt, but not all the steam will condense

all the steam will condense, but not all the ice will melt

All the steam will condense, and all the ice will melt

too close to call

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

absorb

release

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

Absorb

Release

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

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

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?

yes

no, we have steam left over

no, we have ice left over

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?

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?

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?

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

without calculations, guess which of the following will happen.

All the ice will melt, but not all the steam will condense

all the steam will condense, but not all the ice will melt

All the steam will condense, and all the ice will melt

too close to call

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

absorb

release

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

Absorb

Release

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?

yes

no, we have steam left over

no, we have ice left over