Chapter 3: Matter and Energy

What are the types of matter?

* Not states

Pure Substances and Mixtures

Pure Substances have..

a fixed and definite composition

Mixtures

Contain two or more different substances that are physically combined

* Can be physically separated

What are the types of pure substances?

Elements → 1 type of atom (periodic table)

Compounds → 2 or more chemically combined atoms that are always in the same ratio (Water = H₂0)

What are the types of mixtures?

Homogeneous → Uniform composition/ appears the same like milk (although it’s made up of many things)

Heterogeneous → Mixed composition/ appears different like spoiled milk (things are visibly all over)

What are the states of matter (excluding plasma)?

Solid, liquid, and gas

Solids

* Shape
* Volume
* Particle arrangement
* Particle interaction
* Particle movement

**Shape:** Definite

**Volume:** Definite

**Particle arrangement:** Close; Fixed

**Particle interaction:** Very strong

**Particle movement:** Vibrate; Very slow

Liquids

* Shape
* Volume
* Particle arrangement
* Particle interaction
* Particle movement

**Shape:** Indefinite (takes the shape of its container)

**Volume:** Definite

**Particle arrangement:** Close; Mobile

**Particle interaction:** Strong

**Particle movement:** Moderate

Gasses

* Shape
* Volume
* Particle arrangement
* Particle interaction
* Particle movement

**Shape:** Indefinite (takes the shape of its container)

**Volume:** Indefinite (takes the volume of its container)

**Particle arrangement:** Random; Far apart

**Particle interaction:** Essentially none

**Particle movement:** Very fast

What increases the motion of particles?

Heat

Physical Properties

Characteristics observed or measured without changing the composition of a substance

* Shape, physical state, boiling/freezing point, density, color

Physical Change

Occurs in a substance if there is

* State change
* Change in physical shape
* No change in identity and composition of the substance

Chemical Properties

Describe the ability of a substance to become one or multiple different substances

Chemical Change

A new substance forms that has new chemical and physical properties

Temperature

Measure of how fast particles move

* How hot or cold an object is compared to another object

What type of energy is particle motion?

Kinetic energy

What are the temperature scales?

* What kind of unit?

Fahrenheit → U.S Unit

Celsius → Metric Unit

Kelvin → SI Unit

Freezing point of water (all three scales)

**Fahrenheit:** 32°

**Celsius:** 0°

**Kelvin:** 273 K

Boiling point of water (all three scales)

**Fahrenheit:** 212°

**Celsius:** 100°

**Kelvin:** 373 K

Fahrenheit → Celsius Formula

F = 1.8(C) + 32

Celsius → Kelvin Formula

K = C + 273

What is unique about Kelvin?

It is the absolute temperature scale

* No degree sign
* No negatives
* Starts at 0K which the absolute lowest temperature can possibly be

Energy

The ability to do work

* Makes objects move

What are the two main types of energy?

Kinetic and Potential

Kinetic Energy

Energy of motion

* Swimming, water running down a dam, working out

Potential Energy

Stored energy for use at a later time

* Gasoline, coal, food, chemical bonds, compressed spring, water at the top of a closed dam

How is potential energy determined?

By the position of the object and/or the chemical composition of a substance

The ______ particles move the ______ the _______ energy(temperature) of the substance

The ***faster*** particles move the ***greater*** the ***thermal*** energy(temperature) of the substance

Heat

Energy transferred from hot to cold particles

What happens when ice is heated?

The molecules increase motion and eventually have enough energy to change states

\
Solid → Liquid

Unit of Energy

**SI Unit:** Joule(J) or Kilojoules (kJ)

**Metric Unit:** Calories (cal) or Kilocalories (kcal)

* The amount of energy needed to raise the temp of water by 1°C

Joule → Calorie Conversion

4\.184J = 1 cal

* Exact; doesn’t not count toward sig figs

Nutrition

Nourishment or energy obtained from food

Calorimeter

Nutritionists burn food in it

* Measures heat transfer
* The heat released from burning a food sample is used to determine the energy value for that food

Cal (food label) → cal Conversion

1 Cal = 1000 cal

OR basically, 1 Cal = 1 kcal

Specific Heat

The amount of heat that raises the temperature of 1g of a substance by exactly 1°C

* Different for each substance
* The ability of a substance to retain heat

What are the units for specific heat?

* SI and Metric

**SI Unit:** J/g°C

**Metric Unit:** cal/g°C

Specific Heat Formula

heat/(grams x ∆T) = cal(or J)/g°C

Specific heat of water

1\.00 cal/g°C OR 4.184 J/g°C

When ocean water cools, the surrounding air

a. cools

b. warms

c. stays the same

b - the water’s heat is released, warming the air

Sand in the desert is hot in the day and cool at night.

\
Sand must have a

a. low specific heat

b. high specific heat

a - the sand does not retain heat very well

Heat Formula

mass x ∆T x specific heat = cal/J

\
(specific heat must also match the energy unit)

What are the types of state changes and do they absorb or release heat?

S → L = Melting; absorbs heat

L → S = Freezing; releases heat

L → G = Evaporation/Vaporization; absorbs heat

G → L = Condensation; releases heat

S → G = Sublimation; absorbs heat

G → S = Deposition; releases heat

Exothermic

Releases heat

Endothermic

Takes in heat

What type of state change occurs with dry ice?

Sublimation

Heat of Fusion

Amount of heat released when 1g of a liquid freezes at its freezing point

AND

Amount of heat needed to melt 1g of a solid at its melting point

\
Heat released during freezing = Heat needed to melt (for any given substance)

\
w/o changing temperature

Evaporation (water)

Surface molecules gain sufficient energy to become gas

Condensation

Gas looses energy; becomes liquid

Boiling (water)

All molecules gain enough energy to form a gas (vaporize)

* Bubbles of water vapor appear throughout the liquid

Heat of Vaporization

\
\
Amount of heat to change 1g of liquid to gas at its boiling point

AND

Amount of heat released when 1g of gas changed to liquid at its boiling point

\
w/o changing temperature

Sublimation

Surface particles of solid become has directly gas

* No temperature change

\

*Dry ice goes through sublimation at 78°C*

Deposition

Gas particles to solids

* Doesn’t pass through the liquid stage

True or False: As a solid melts, its temperature does not change

True; the absorbed heat is used to break the forces of attraction between particles, not to heat the substance

What is the caloric value per gram of carbohydrates, proteins, alcohol, and fats?

**Carbohydrates:** 4 calories per gram

**Proteins:** 4 calories per gram

**Alcohol:** 7 calories per gram

**Fats:** 9 calories per gram