Chapter 3 States of Matter

Solids, Liquids and Gases3.1

States of Matter

Imagine that you have a baseball and a small packet of ketchup.

1. If you squeeze the ketchup packet, how would it change?

The shape of the packet would change. 2. If you squeeze the baseball, how would it

change? The baseball would not change shape in any

noticeable way. 3. What would these results tell you about the

properties of solids and liquids? You may say that solids have a shape that

doesn’t change under ordinary circumstances but that a liquid can change shape (flow) as the shape of its container changes.

Describing MatterMaterials can be classified as

solids, liquids or gases based on whether their shapes and volumes are definite or variable.◦Shape and volume are clues to how

particles within something are arranged

SolidsWhat do a pencil, quarter, book or

cafeteria tray have in common?◦A recognizable shape and they take up a

certain amount of space. ◦They are all in a solid state

Solid is the state of matter in which materials have definite shape and volume.◦Definite means that the shape and volume

won’t change (as you move it) but obviously a pencils changes shape if you sharpen it

LiquidsDemo

◦Appearances are deceivingA liquids always has the same

shape as its container and can be poured from one container to another

A Liquid is the state of matter in which a material has a definite volume but not a definite shape.

GasesWhat are some different gasses

that you know?◦Air is a mixture of gases ◦Natural gas or butane

Gas is the state of matter in which a material has neither a definite shape nor volume. ◦A gas takes the shape and volume

of its container.

AtomsThe ‘shape’ and

‘volume’ of the Helium in the balloon is the same as the balloon itself.

The Helium atoms in a balloon are not arranged in a regular pattern.◦ They are spaced

randomly throughout the balloon.

Arrangement of atoms in solids, liquids and gases

Other states of matterOn earth, almost all matter is a solid, liquid or

gasOther places in the universe, matter exists in

other states. At extremely high temperatures, matter can

exist as plasma. (Such as on the Sun)Einstein also predicted a fifth state of matter

that would exist at extremely low temperatures (-273C).◦ Groups of atoms would behave as a single particle◦ Scientists were able to replicate this temperature

ad found there was a 5th state of matter called the Bose-Einstein condensate (BEC)

Kinetic theoryWhy is copper normally a solid,

mercury a liquid and helium a gas?Because the particles inside are

moving at different rates – with different amounts of kinetic energy

Kinetic Energy is the energy an object has due to its motion◦The fast an object moves the greater is

kinetic energy. (What kind of proportion is this?)

◦The Kinetic theory of matter says that all particles of matter are in constant motion.

Behavior of GasesThe motion of

particles in a gas are similar to the motion of balls in a game of pool. The ball moves in a straight line until it strikes another ball. Both balls change course. Kinetic energy is transferred during those collisions.

Motion in GasesThe particles in a gas are ever at rest. Average speed of particles in a gas is

1600km/hrParticles are not all moving at the same

speed, some are slower and some faster

What can happen to the kinetic energy of 2 He atoms when the atoms collide?◦ one atom may gain kinetic energy and

speed up while the other atom loses kinetic energy and slows down.

Behavior of LiquidsDo particles in liquids have kinetic energy?

◦ Yes! So- why does mercury have a definite volume at room temperature instead of expanding to fill its container? The average speed of a mercury (HG) atom is much slower than

the average speed of a helium atom.

The particles in a liquid are more closely packed than the particles in a gas. ◦ Think of going through the hallway before the bell rings

and after the bell rings – which can you do faster? ◦ A liquid takes the shape of its container because

particles in a liquid can flow to new locations. ◦ The volume of a liquid is constant because forces of

attraction keep the particles close together. Therefore, particles in a liquid cannot spread out and fill the

container

Behavior of SolidsWhat is it like in a movie theater?

◦Each person remains in the same location- a ‘fixed’ location and the total volume does not change

This is what solids are likeSolids have a definite volume

and shape because particles in a solid vibrate around a fixed location.

Lab Oobleck

The Gas Laws3.2

3.2 The Gas LawsWhat happens when you shake up

a soda?◦It builds up pressure- but where does

the pressure come from?◦CO2 gas is released as you shake it up

Pressure is the result of a force distributed over an area. ◦when you shake up the soda bottle,

pressure builds up and causes a force to be distributed over the area inside the bottle

PressureThe SI Unit of pressure comes from

the units for force and area.◦Force is measured in newtons (N) ◦Area is measured in meters (m2)

When a force in newtons is divided by an area in m2, the unit of pressure is newtons per square meter (N/m2)

the pascal (Pa), is shorthand for N/m2

◦A pascal is very small, so in science we often use kilopascals (kPa)

PressureGas pressure is produced by particles

colliding with the walls of a container (like a balloon)

When so many particles collide with the walls of the container simultaneously, they produce a measurable pressure.

Collisions between particles of a gas and the walls of the container cause pressure in a closed container.

What do you think happened here?

A real example of where a ‘can’ gets crushed by air pressure! The tanker was carrying hydrocarbon fuel – why do you think it crushed after being emptied and then being transported up a mountain? What affects can effect Gas Pressure?

Factors that Affect Gas PressureWhat are the particles of a gas doing?What factors could affect those

particles? How else could gas pressure be affected?◦Particles could move faster or slower◦ you could move the gas from a larger

container to a smaller one◦You could add or remove gas from the

containerFactors that affect pressure in a closed

container are: temperature, volume, and the number of particles.

Temperature Raising the temperature of a gas

will increase its pressure if the volume of the gas and number of particles are constant.

If the temperature goes up the average kinetic energy goes up and the particles move faster.

The particles collide with the wall of the container more often and with more force, increasing the pressure.

Number of ParticlesIncreasing the # of particles will

increase the pressure of a gas if the temperature and volume are constant.

What happens if you keep blowing air into a balloon?

VolumeReducing the amount of volume

of a gas increases its pressure if the temperature of the gas and number of particles are constant.

If I have the same amount of particles in a smaller container, will the pressure be increased?

ExampleVolume and Pressure are factors when you

breatheAs you inhale, the diaphragm contracts causing

your chest cavity to expand. This increases the volume and allows the particles

in air to spread out, lowering the pressure in your chest.

The pressure outside your body is now greater than inside and air rushes into your lungs.

How does the movement of your rib cage affect your chest cavity?◦ The volume increases as the rib cage is lifted up and

out. The volume decreases as the rib cage moves down and in.

Gas LawsThere are several gas laws that

describe the behavior of gas. ◦Boyle’s Law, Charles’s Law and the

combined gas law.◦We also have 4 variables that we use

when describing gases: Temperature (T) Pressure (P) Volume (V) And the amount of gas which is

expressed in number of moles (n)

Charles’s LawJacques Charles (the

inventor of the hydrogen balloon) studied the behavior of gases.

He discovered that when he graphed volume vs. temperature of gases that as the volume of a gas increases, the temperature of the gas also increases.

Charles’s law states that the volume of a gas is directly proportional to its temp in K if the pressure and number of particles is constant.

The mathematical expression is

V1 = V2

T1 T2

Boyle’s LawRobert Boyle described

the relationship between pressure and volume.

If the volume of a cylinder is decreased, the pressure increases.

Boyle’s Law states that the volume of gas is inversely proportional to its pressure if the temperature and number of particles are constant.P1V1=P2V2

The Combined Gas LawBoyle’s Law and Charles’s Law

can be combined to form one law called The Combined Gas Law

This law describes the relationship between temperature, volume and pressure of a gas.

The combined gas law can be used to solve problems involving gases.

The Combined Gas Law

Section 3.2

The Combined Gas Law

Section 3.2

The Combined Gas Law

Section 3.2

The Combined Gas Law

Section 3.2

Math PracticePg 80 1, 2 and 3. Don’t forget temperature

conversions!