Changes of State Name:

Change of State

The particles of a substance move differently depending on the state of the substance. The particles also have different amounts of energy when the substance is in different states.

For example, particles in liquid water have more energy than particles in ice. But particles of steam have more energy than particles in liquid water.

Read

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To change a substance from one state to another , you must _______ or _________ energy.

A _______ is the change of a substance from one physical form to another.

Melting: Solid to Liquid

One change of state that happens when you add energy to a substance is melting.

Melting is the change of state from a solid to a liquid.

This change of state is what happens when ice melts.

Adding energy to a solid increases the temperature of the solid.

Read and Understand

List examples for each of the following. An example for melting could be a popsicle

in the sun.

True or False

Double click in the blank area and type your answer for each statement.

ENDOTHERMIC

For a solid to melt, particles must overcome some of their attractions to each other.

When a solid is at its melting point, any energy added to it is used to overcome the attractions that hold the particles in place.

Melting is an endothermic change because energy is gained by the substance as it changes state.

Read and Understand

Exothermic

For a liquid to freeze, the attractions between the particles must overcome the motion of the particles.

Imagine that a liquid is at its freezing point. Removing energy will cause the particles to begin locking into place.

Freezing is an exothermic change because energy is removed from the substance as it changes state.

Read and Understand

Watch the film.

Endothermic Reaction

Exothermic Reaction

antacid being dropped in water

burning paper

mixing water with potassium chloride

using dynamite

Grab and drag the statements below to the correct column.

What do you know?

Energy is neither _________________ or ____________.

______________________ releases energy and gives off heat.

_________ is given off in an exothermic reaction.

___________________ absorbs energy resulting in lowering of temperatures.

created exothermic reaction endothermic reaction

heat destroyed

Click on the words below and move to the proper blank space.

EVAPORATION

Evaporation is the change of a substance from a liquid to a gas.

Evaporation can occur at the surface of a liquid that is below its boiling point.

For example, when you sweat, your body is cooled through evaporation.

Evaporation also explains why water in a glass disappears after several days.

Read and Understand

List 3 places that you have seen evaporation take place.

Watch the film

What do you know?

When a liquid changes to a gas it is called ___________.

When liquid molecules are ___________ the molecules move very _______________.

How quickly water evaporates depends on how much heat is _____________.

Fill in the blanks.

TRUE of FALSE

Boiling Point

Boiling is the change of a liquid to a vapor, or gas, throughout the liquid.

Boiling occurs when the pressure inside the bubbles, which is called vapor pressure, equals the outside pressure on the bubbles, or atmospheric pressure.

The temperature at which a liquid boils is called its boiling point which is 100°C.

No matter how much of a substance is present, neither the boiling point nor the melting point of a substance change. For example, 5 mL and 5 L of water both boil at 100°C.

Read and Understand

Watch the film

Fill in the Blanks What is needed to change any form of matter

____________________.

How do you change a solid into a liquid? ____________

When solids change to a liquid it is called ____________.

When liquids change to a solid state they have _________.

Liquid in a gaseous state is called ____________.

_________________ is a clear gas that is impossible to see.

_______________ is the process by which a gas turns into a liquid.

add heat

change of temperature

melting

vapor condensation

Water vapor

solidified

Condensation

Condensation is the change of state from a gas to a liquid.

Condensation and evaporation are the reverse of each other.

The condensation point of a substance is the temperature at which the gas becomes a liquid.

The condensation point is the same temperature as the boiling point at a given pressure.

Read and Understand

Watch the Film

Place each phrase under the correct column.

2. When a gas is heated the molecules will slow down.

1. If the temperature is cooled enough then the droplets

will turn into ice crystals.

3. When a gas cools enough it changes to a liquid. this is called evaporation.4. If the temperature stays warm

then the droplets stay as a liquid

TRUE FALSE

Sublimation

Sublimation is the change of state in which a solid changes directly into a gas.

Dry ice is much colder than ice made from water.

For a solid to change directly into a gas, the particles of the substance must move from being very tightly packed to being spread far apart.

So, the attractions between the particles must be completely overcome.

Watch the Film

Fill in the Blanks ________ is the process of a gas changing to a

liquid.

__________ is the process of a liquid changing to a solid.

Freezing point is the temperature at which a ________ becomes a ___________.

The process of going from a solid directly to a gas is called _____________.

sublimationcondensation freezingsolidliquid

Quick Quiz True or False

Quick Quiz---continued

What are two changes of state that are endothermic?

Do the particles of a substance move faster or slower as the substance is heated?

When water evaporates, has a chemical change or a physical change occurred?

Click in the blank area below each question and answer it.

Quick Quiz---True/False