KMT & Fluids

Question 1

Definition of Matter

Answer 1

Matter: Anything that has mass and takes up space (volume).

Question 2

Key Points of the Particle Theory / Kinetic Molecular Theory (KMT):

Answer 2

All matter is made up of tiny particles.
Particles are always moving.
There are spaces between particles.
Particles move faster when heated and slower when cooled.
Particles are attracted to each other – stronger in solids, weaker in gases.

Question 3

Application of KMT
States of Matter

State Particle Motion Shape & Volume Compressibility

Answer 3

Solid Vibrate in place Fixed shape Very low
Liquid Slide past each other Takes container shape Slightly
Gas Move freely & rapidly No fixed shape or volume High

Question 4

Application KMT

2. State Changes

Answer 4

Melting, Freezing, Boiling, Condensing, Sublimation
Changes in energy and particle motion explain changes of state.

Question 5

What is sublimation

Answer 5

solid to the gaseous state

Question 6

What is condensing

Answer 6

Gas to liquid or gas to solid

Question 7

What is melting

Answer 7

Soldi to liquid

Question 8

What is freezing

Answer 8

Liquid to solid

Question 9

What is boiling

Answer 9

Liquid to gas

Question 10

Application kmt
3. Temperature Effects

Answer 10

Increased temperature = more energy = faster particles
Solids → Liquids → Gases (with increasing energy)

Solids: Heat = more vibration.
Liquids: Heat = faster flow.
Gases: Heat = faster, more spread out.

Question 11

Fluids: Liquids and Gases

1. Compressibility

Answer 11

Gases: Compressible (lots of space between particles)
Liquids: Not compressible (particles close together)

Question 12

Fluids: Liquids and Gases

Viscosity

Answer 12

Resistance to flow
High viscosity = thicker (e.g., honey), Low = flows easily (e.g., water)

Question 13

Measuring Matter

Answer 13

Mass (grams, kg)
Volume (mL, cm³)

Question 14

Density

Word Equation:

Answer 14

Density = Mass / Volume

Question 15

Units for density

Answer 15

Units:
g/mL (for liquids)
g/cm³ (for solids)

Question 16

Density
Characteristic Property:

Answer 16

Characteristic Property:
Same for a specific substance (used to identify it)

Question 17

Average Density:

Answer 17

Total mass / Total volume (used for composite or hollow objects)

Question 18

Temperature Effects
Density

Answer 18

Heating = expansion = volume ↑ → density ↓
Gases most affected; solids and liquids less so

Question 19

Effect of Temperature SLG Densities

Answer 19

State Temp ↑ → Density
Solid Slight ↓
Liquid ↓
Gas ↓ (significant)

Question 20

Ice vs Water

Answer 20

Ice floats because it is less dense than liquid water.

Question 21

Floating and Sinking
Key concepts

Answer 21

An object floats if it is less dense than the fluid.
Buoyant Force: Upward force exerted by fluid (measured in Newtons, N).

Question 22

Floating and sinking

Applications

Answer 22

Fish & Submarines: Control buoyancy by adjusting average density.
Hot Air Balloon: Hot air = less dense, causes it to rise.
Submarine: Takes in water to increase density and sink.

Question 23

Viscosity of Fluids

🧪 Definitions:

Answer 23

Viscosity: Resistance to flow.
Fluids: Substances that flow (liquids and gases).

Question 24

Measuring Viscosity:

Answer 24

Flow Rate Test or Drop Time Test.
Variables:
Independent: Temperature or type of fluid.
Dependent: Time it takes to flow.
Controlled: Volume, surface angle, etc.

Question 25

Effect of Temperature: viscosity

Answer 25

Fluid Type Temp ↑ → Viscosity Liquids ↓ (flows more) Gases ↑ (more resistance)

Question 26

KMT Explanation:

Answer 26

Heat makes particles move faster → affects flow behavior. In liquids: particles slide easier → less viscosity. In gases: faster movement = more collisions → more viscosity.

Question 27

What is the density of water

Answer 27

1.0 g/mL

Question 28

Denisty of ice aluminum iron and gold

Answer 28

Substance Density (g/cm³) Water 1.0 Ice 0.92 Aluminum 2.7 Iron 7.9 Gold 19.3

Question 29

Examples of Characteristic Properties:

Answer 29

Property Why it's Characteristic Density Always the same for pure substances (e.g., gold = 19.3 g/cm³) Melting Point Ice melts at 0°C no matter the amount Boiling Point Water boils at 100°C at sea level

Question 30

Submarines vs Hot Air Balloons

Answer 30

Feature Submarine Hot Air Balloon Fluid they move in Water (liquid) Air (gas) Type of fluid system Hydraulic / incompressible fluid Pneumatic / compressible gas How it rises/falls Changes overall density by taking in or releasing water in ballast tanks Changes air temperature in the balloon to change air density Key concept used Buoyancy & density Buoyancy & density Buoyant force direction Upward (in water) Upward (in air) Compressibility Water is not compressible → stable movement Air is compressible → fast response to temperature changes A boat floats because it pushes away (displaces) a lot of water, and the water pushes back up. A helium balloon floats because helium is less dense than air.

Question 31

What is Buoyancy?

Answer 31

When you put something in water (or air), the fluid pushes up against it. If that upward force is strong enough, the object will float.

Question 32

What determines if something floats?

Answer 32

Situation What happens Object is less dense than fluid It floats Object is more dense than fluid It sinks Object has equal density to fluid It hovers/suspends

Question 33

How does a submarine rise and sink?

Answer 33

By changing its average density using ballast tanks.

Question 34

Q: How does a hot air balloon rise?

Answer 34

A: By heating the air inside to make it less dense than the air outside.

Question 35

What determines if something floats or sinks?

Answer 35

A: Its density compared to the fluid’s density.

Question 36

What is a characteristic property?

Answer 36

: A property that doesn't change with sample size and can identify a substance (e.g., density, boiling point).

Question 37

Q: What happens to the viscosity of a liquid when it's heated?

Answer 37

It decreases (flows more easily).

Question 38

If a metal block has a mass of 100 g and a volume of 20 cm³, what is its density?

Answer 38

: 5 g/cm³ (Density = 100 ÷ 20)

Question 39

What is the unit for buoyant force?

Answer 39

Newtons (N)

Question 40

Why does a steel ship float even though steel is denser than water?

Answer 40

he ship’s shape displaces enough water to lower its average density.

Question 41

Q: What principle explains why objects float or sink?

Answer 41

Archimedes’ Principle

Question 42

Which flows faster: water or honey?

Answer 42

Water – it has lower viscosity.

Question 43

What would run down a ramp faster: a high or low viscosity fluid?

Answer 43

Low viscosity means the fluid flows easily and with less resistance (like water or vegetable oil). High viscosity fluids are thicker and flow more slowly (like honey or syrup).

Question 45

Does a subirmine change OAD or Voulume

Answer 45

Submarine = OAD Hot hair balloon = Volkume (larger the volume= lower the density)