Solids, Liquids and Gases

Use what you know about particles in a gas to explain why a gas has no definite shape and no definite volume.

A gas has neither a definite shape nor volume because its particles spread apart and move freely in all directions.

Crystalline solid

A solid that has a specific structure (crystals, salt sugar)

Amorphous solid

A solid whose atoms are randomly arranged (eraser).

Liquid

A substance where molecules are spread out and takes the shape of that object. Volume does not change. The reason it has no definite shape is because the particles are free to move around each other.

solids

An object that stays the same shape (without outside help) at room temperature. Always has definite shape and volume because the particles are touching each other and can't move around or past each other.

Describe how motions of gas particles are related to the pressure exerted by gas.

As the movement of gas particles collide with walls of their container they push on the container walls. The more often the particles hit the container walls the greater their pressure will be.

Boyle's Law

As the pressure of a gas increases the volume decreases. As the pressure of a gas decreases the volume increases. They have an opposite relationship (as one goes up the other goes down).

How does Boyle's Law describe the relationship between gas pressure and volume?

At a constant temperature when gas pressure increases, gas volume decreases.

Gas to a liquid (condensation)

Atoms are moving less and move closer (losing heat/energy). Particles lose energy and form a liquid.

Liquid to a gas (evaporation)

Atoms are moving more and spreading out (add heat/energy).

Solid to gas (sublimation)

Atoms spread out and move a lot. Particles of a solid go straight to gas skipping the liquid state.

Solid to liquid (melting)

Atoms start to move and spread out. Add heat (energy) and so the particles are vibrating fast enough that they are able to break apart (from solid state).

Solid to liquid (freezing)

Atoms stop moving and get closer (losing heat/energy). Particles are moving so slowly they begin to form a pattern.

How does the positions and movements of particles of a liquid help to explain the shape and volume of a liquid?

Because particles can move freely around and so a liquid takes the shape of its container.

Suppose it is the night before a big parade and you are in charge of inflating the parade balloons. You just learned that the temperature will rise between early morning and the time the parade will start. How will this information change the way you inflate the balloons?

Because you know that the temperature will increase the volume o the gas in the ballons will also increase. To prevent this expansion from bursting the balloons you should not completely fill the ballons.

How do crystalline solds differ from amorphous solids?

Crystalline has a definite pattern and amorphous does not.

Explain why a sewing needle can float on the sufrace of water in a glass/

Due to surface tension.

How is gas pressure defined?

Gas pressure is the force of its outward push divided by the area of the walls of its container.

A glas blower can bend and shape glass. Is it a crystalline or amorphous solid?

Glass is an amorphous solid and becomes softer and softer as it is heated.

Gas

Particles that move through space freely and has no definite shape or volume. Fill up all the space available and the reason it takes the shape and volume of their container.

What are the general characteristics of a solid?

Solids have a definite shape and volume.

What process occurs as pieces of dry ice get smaller?

Sublimation

Fluid

Substance that can flow (liquid).

Change of state

The change in state (from solid to liquid or liquid to gas or other way around) due to either the loss or gain of energy.

Why does pumping more air into a basketpall increase the pressure inside the ball?

The greater number of gas particles inside the basketball result in more collisions which increase the outward push of the gas.

What happens to the particles of a solid when it becomes a liquid?

The particles break free from their fixed position and begin to move about.

What determines the shape and volume of a gas inside a container?

The shape and volume of a gas are the same as those of their container.

Melting point

The temperature at which melting occurs.

How does thermal energy of a solid water change as it melts?

The thermal energy increases.

How may solids be described (shape and volume)?

They don't have a definite shape but do have a definite volume.

Viscosity

Thickness of a liquid (resistance to flow). For example lava is viscous and milk is not viscous.

Surface Tension

Water is really attracted to itself so it clumps and forms a skin on the surface.

Charle's Law

When temperature of a gas increases the volume increases. When the temperature of a gas decreases the volume decreases. They have a direct (same) relationship meaning if one goes up the other goes up and if one goes down the other goes down (move in the same direction).

Explain why increasing the temperature of a gas enclosed in a rigid container causes the pressure in the container to increase.

When the temperature increases gas particles move faster and collide with the walls of their container more frequently and with greater force. If the container is rigid its volume cannot change to sht e pressure increases.

Why does evaporation of sweat cool your body on a warm day?

Your bodies is applying the thermal energy necessary to change the sweat from liquid to gas causing the body to lose heat and become cooler.