Chapter 7:

Mix and Flow of Matter

Law of Conservation of Energy: (30 secs)

Energy can change form (S,L,G) but the total amount of energy stays the same.

7.1 States of Matter:

• MATTER: is anything that has mass & volume.

• MASS: is the quantity of matter a substance or object contains. Usually measured in grams (g) or

kilograms (kg).

• VOLUME: is the amount of space taken up by a substance or object. Volume is usually measured in millilitres

(mL), litres (L), or cubic centimetres (cm3).

See pages 246 - 247

Comparing the basketball and bowling ball, which has more mass? Volume?

7.1 States of Matter:

The four familiar states (phases) of matter. Fixed mass Fixed Volume Fixed Shape

Solid Yes Yes Yes

Liquid Yes Yes No

Gas Yes No No

Plasma Plasma exists on earth as lightning, auroras, and neon. Exists due to nuclear fusion.

See pages 246 - 247 solid liquid gas plasma

The Particle Model of Matter • All matter is made of small particles that are too

small to see. • There are spaces between the particles. The

amount of space varies depending upon the state. • The particles are always moving. • The particles are attracted to one another. • Plasma is not commonly talked about in the Particle

model of matter.

See page 248

Mini-Quiz: 1) How is a solid different from a liquid in shape

and volume? 2) How does the behaviour of particles change as

energy is added? How does the behaviour change as energy is lost?

3) Which particles are the furthest apart? Solids, liquids or gases?

Answer in full sentences. (do not write down the question)

Mini-Quiz Answers:

1) A Solid has tightly packed molecules that hold a definite shape. A liquid takes the shape of the container and particles are further apart.

2) As energy is added, particles move faster and further apart. Heat is caused by the friction produced when particles run into each other.

3) Solids: closest together, only vibrate. Liquids: further apart, slide past one another. Gases: Very far apart, move around quickly.

• Kinetic Energy: is the energy due to motion.

• The Kinetic Molecular Theory (KMT): explains what happens to matter when the kinetic energy of the particles changes. A theory provides a scientific

explanation based on the results of experimentation. See page 249

As the rollercoaster’s speed increases, its kinetic energy

also increases.

The Kinetic Molecular Theory:

The Kinetic Molecular Theory: (KMT)

The main points of the kinetic molecular theory include:

See page 249

1. All matter is made of very small particles. 2. There is empty space between particles. 3. Particles are constantly moving. The particles are

colliding with each other and the walls of their container. 4. Energy makes particles move. The more energy the

particles have, the faster they move and further apart they get.

Solid: Particles are so tightly packed together they cannot move freely. They can only vibrate.

Liquid: Particles are farther apart and they can move by sliding past each other.

Gas: Particles are very far apart and move around quickly.

Thermal Expansion & Contraction:

• Thermal expansion: is the increase in volume of a substance when its temperature is raised.

• Thermal contraction: is the decrease in volume of a substance when its temperature is lowered.

See page 250

Can you use the concepts of thermal expansion and contraction to explain how a thermometer works?

The Difference Between Heat & Temperature:

• Thermal energy: is the total kinetic energy of all the particles in the substance.

• Heat: is the transfer of thermal energy between two materials of different temperature. Goes from higher temperature to

lower temperature. • Temperature: is the average

kinetic energy of the particles in a substance. See page 251

Changes of State

Name Change of State (from _ to _)

Heat Gained Heat Lost

Melting Solid to liquid

Evaporation Liquid to gas

Condensation Gas to liquid

Solidification Liquid to solid

Sublimation Solid to gas

Deposition Gas to solid

See pages 252 - 253

•Melting point: (M.P.) is the temperature at which solid turns to liquid (Same # as freezing point). •Boiling point: (B.P.) is the temperature at which liquid turns into gas.

Changes of State

See pages 252 - 253 Take the Section 7.1 Quiz

Solid

Melting

Liquid

Boiling

Gas

7.2 Fluids and Density

A fluid is any form of matter that can flow. Liquids & gases are fluids since they do not have

a fixed shape. Solids are not fluids.

See page 260 Lava, water, and syrup are examples of fluids.

Solid, Liquid, & Gas Density

Density: is the amount of mass for each unit of volume.

Density describes how closely packed together the particles are in a material.

See page 261

Describe the spacing of the particles in the solid block, liquid water, and gaseous air.

Most substances are denser in their solid form than in their liquid form, but water is an exception.

Layers of Fluids

Fluids that do not mix, layer themselves according to their density.

Less dense fluids “float” on top of more dense fluids.

See pages 262 - 263

Can you list the objects, in this beaker, from most dense to least dense?

oil

ball

water

Measuring Density

Both mass & volume are required when calculating density.

Mass: Mass can be measured using a scale or

balance. Volume:

For objects that are block shaped, volume can be calculated by measuring the block and then using the equation: volume = length x width x height.

For objects with irregular shape displacement is the method used to find the volume. See page 264

balance

More About Density: Answer the following questions…

Density: is the mass of a given volume. (Describes how close particles are in a material).

Check your understanding: Answer the “What to do” questions #1 - 6 on Density. (page 262)

Answers will be on a following slide. (You can work with a partner)

“What to Do” Answers: (Pg 262)

1. Gold 19.32 g/cm cubed 2. Hydrogen 0.00009 g/mL 3. Mercury is denser than lead 4. Styrofoam, cork and oak are less dense than

water (water always has a density of 1 g/mL). 5a) Anything less than 1 g/mL will float in water. 5b) Anything denser than 1 g/mL will sink in water. 6. Iron, nickel, copper, aluminium, and lead are

less dense than mercury.

Units of Measurement: (don’t forget!)

Mass: grams (mg, cg, kg, etc…) Volume: -cm3 (solid) -mL (fluid)

Remember: a fluid is a liquid or gas.

Density: -g/cm3 (solid) -g/mL (fluid)

Calculating Density Density can be calculated using the

following formula:

Answer the following: What is the density of a 4 cm3 rock

that has a mass of 24 g?

A 5 ml sample of motor oil has a mass of 4.5 g. What is the density of the motor oil?

See page 265 See next slide for the answers.

Calculating Density

Density can be calculated using the following formula:

Answer the following: What is the density of a 4 cm3 rock

that has a mass of 24 g? A 5 ml sample of motor oil has a

mass of 4.5 g. What is the density of the motor oil?

See page 265

Answers • 6 g/cm3

• 0.9 g/mL

Take the Section 7.2 Quiz

More Density Practice:

1. What is the density of a 2 cm3 sugar cube that has a mass of 3.18 g?

2. A 3 mL sample of oil has a mass of 2.64 g. What

is the density of the oil?

3. The mass of a 1 cm3 of lead is 11.34 g. The mass of 1 cm3 of iron is 7.87 g. Which solid has the greater density?

Density Answers:

1) 1.59 g/cm3 2) .88 g/mL 3) Lead Reminder: Highest number = highest

density. (Water has density of 1 g/ml) Use your units! g/cm3 (Solids) and

g/mL (liquids and gases)

Measuring Density Reminders:

Recall: Density is the mass of a given volume. To find density, you need to know the mass and volume of an object.

Mass: found with scale or triple beam balance. Volume: often measured in cubic centimeters (cm3). Volume = length x width x height Displacement: used to measure irregular shapes

like rocks for example. Simple place the rock in a measuring beaker and record how much the water level rises.