1. Physical Change
2. Chemical Change

1. Substance changes form or state only. Boiling, melting, freezing, dissolving, grinding, cutting
2. Where new substances are formed with new chemical and physical properties. Oxygen and hydrogen form water; sodium and chlorine form salt (sodium chloride)

Gas: neither definite shape nor volume

Liquid: definite volume; takes shape of container

Solid: definite size and shape

Phase

Two examples

A sharply defined, uniforme region in a mixture.

Examples- oil and vinegar in salad dressing; ice and water in a frozen pond

Density

General equation and three standard units

The mass of a unit volume of a substance.

Density = mass/volume

g/mL g/L kg/L

Density = mass/volume

density 10 g/5 mL = 2 g/mL

Element

List some examples

A substance composed of identical atoms.

gold, silver, oxygen, hydorgen, lead, chlorine, helium, iron, copper, fluorine, arsenic

Compound

List some examples

Substance composed of two or more different elements chemically combined. For example:

Water - H₂O

Salt - NaCl

Sugar - C₆H₁₂O₆

Ammonia - NH₃

Mixture

List some examples

A combination of substaces held together by physical means.

(Dirt, milk, soup, saltwater, granite)

Homogenous ang heterogenous Mixture

Give example

Homogeneous mixtures are uniforme in composition. (Air, metal, alloy, salt water)

Hetergeneous mixtures are not uniform in composition. (Dirt, spaghetti sauce)

Symbols for:

1. Barium
2. Beryllium
3. Platinum
4. Arsenic
5. Tin

1. Ba
2. Be
3. Pt
4. As
5. Sn

Symbols for:

1. Sodium
2. Potassium
3. Calcium
4. Hydrogen
5. Magnesium

1. Na
2. K
3. Ca
4. H
5. Mg

Names for:

1. Fe
2. Co
3. Ni
4. Cu
5. Zn

1. Iron
2. cobalt
3. Nickel
4. Copper
5. Zinc

Symbols for:

1. Silver
2. Gold
3. Mercury
4. Aluminum
5. Lead

1. Ag
2. Au
3. Hg
4. Al
5. Pb

Names for:

1. C
2. Si
3. N
4. P
5. O

1. Carbon
2. Silicon
3. Nitrogen
4. Phosporous
5. Oxygen

Symbols for:

1. Sulfur
2. Fluorine
3. Chlorine
4. Bromine
5. Iodine

1. S
2. F
3. Cl
4. Br
5. I

Names for:

1. He
2. Ne
3. Ar
4. Kr
5. U 

1. Helium
2. Neon
3. Argon
4. Krypton
5. Uranium

The sum-total of mass and energu remains constant in a reaction but mass and energy may be interconverted.

E = mc²

E= energy; m = mass

c= speed of light

Identify as element, compound, or mixture

Sand, air, gold, water, salt, hydrogen

Sand - mixture

Air - mixture

Gold - element

Water - compound

Salt - compound

Hydrogen - element

1. Physical Properties
2. Chemical properties

1. Properties which can be observed without changing the substance into something different. Color, odor, hardness, density, luster, state, conductivity, solubility, boiling and melting points.
2. A chemical property is observed when a substance changes into a new substance. Iron forms rust in air and water; gasoline burns in oxygen.

PRESSURE

Write Normal Atmospheric Pressure in Five Standard Units

Pressure is force per unit of area

1 atmosphere= 760 torr

= 760 mm Hg

= 101.3 kilopasca;s

= 14.7 pounds/square inch

1. Barometer
2. Manometer

1. An instrument, invented by torricelli in 1643, which measures atmospheric pressure. An evacuated glass tube in which a column of mercury rises or falls with change in pressure.
2. An instrument used to measure pressure of gases in a closed container.

State three postulates of:

The Kinetic

Molecular

Theory of gases

1. Matter is composed of very small particles; a gas is mostly empty space.
2. Particles are in constant random motion.
3. Collisions are elastic

State the formula for Graham's Law of Diffusion.Do heavy or light gases diffuse faster?

A mixture of a gas A & B:

(R_A)(MW_A)^1/2 = (R_B)(MV_B)^1/2

MW_A,MW_B = Molecular weights

R_A, R_B = Rates of Diffusion

(Light gases diffuse faster)

Charles' Law

V₁/T₁ = V₂/T₂

Pressure and amount of gas are constant

V = volume

T = Kelvin

At 300 K a gas has a volume of 10 liters. Find the volume at 400 K

Use Charles' Law,

V₁/T₁ = V₂/T₂

10/300 = V₂/400

V₂ = 13.3 L

Boyle's Law

P₁ x V₁ = P₂ x V₂

Pressure and volume are inverse if temperature and amount of gas are constant

P = pressure

V = volume

A sample of gas has a volume of 23 L at 800 torr. find the volume at 400 torr.

Use Boyle's Law

P₁ x V₁ = P₂ x V₂

25 x 800 = 400 x V₂

V₂ = 50 L

P₁V₁/T₁ = P₂V₂/T₂

Amount of gas is constant

P = pressure

V = volume

T = kelvin

Dalton's Law of Partial Pressure

In a gas mixture, the total pressure equals the sum of the partial pressures of each component

P_total = P₁ + P₂ + P₃ ...

Ideal Gas Law

PV = nRT

P = pressure (Atmospheres)

V = volume (Liters)

n = # of Moles

R = 0.0820 L-ATM/MOL-K

T = temperature in K

How many moles of H₂ gas are there in 20 L at 4 atm and 400 K?

Use the Ideal Gas Law

PV = nRT

(4 atm)(20 L) = n(0.082)(400)

n = 2.44 moles

1. STP
2. Gay-Lussac's Law of Combining Gas Volume

1. Standard temperature (0° C or 273 K) and standard pressure (1 atmosphere or 760 torr)
2. When only gases are involved in a reaction, the volumes of reactants and product are in a small, whole number ratio.

1. Avogadro's Law (regarding gases)
2. What is the volume of 1 mole of any gas at STP

1. Under the same conditions of temperature and pressure; equal volumes of gases contain equal numbers of moles.
2. 22.4 L

N₂ + 3H₂ ↔ 2NH₃

In the above reaction how many L of NH₃ will be produced from 6L H₂

According to Gay-Lussac's Law the volumes of gases are in direct proportion to the coefficients in the equation.

H₂ : 3/6 L = NH₃ : 2/x

x = 4L of ammonia

Sublimation

The change from a solid to a vapor without the forming of a liquid

Compounds which show sublimation

(CO₂, I₂)

Describe a phase change from liquid to gas

When a molecule gains enough kinetic energy to overcome the intermolecular attractive forces within a liquid, it escapes the surface and becomes gas.

1. Phase equilibrium
2. Dynamic equilibrium

1. For a liquid in a closed container; when the rates of evaporation (liquid to gas) and condesation (gas to liquid) equalize: the concentration of each is stable.
2. In a closed container where opposing changes are taking place at equal rates; the concentration of all components remains constant.

Normal Boiling Point

The temperature at which a liquid phase becomes a gas phase when vapor reaches atmospheric pressure.

Pressure = 1 atm

Define:

1. Critical temperature
2. Critical pressure

1. The temperature above which the liquid phase of a substance can no longer exist.
2. Minimum pressure required to liquify a gas at its critical temperature

Melting Point

The temperature at which the solid and liquid phases co-exist

1. Heat of fusion (value for water)
2. Heat of vaporization (value for water)

1. The amount of energy required to change a gram of substance from liquid at its melting point. (Water - 80 calories/gram)
2. The amount of energy required per gram to change a liquid to gas at its boiling point. (Water - 540 calories/gram)

1. Triple point
2. Vapor pressure

1. The only temperature and pressure combination at which the 3 phases of a substance (solid, liquid and gas) can co-exist at equilibrium
2. The pressure the gas phase exerts on its liquid phase in a close container. This pressure varies with temperature.

Define boiling point in terms of vapor pressure

The temperature at which the vapor pressure over a liquid reaches atmospheric pressure. The substance boils (liquid to gas)

1. How much heat is required to change 10 grams of water to steam at 100° C
2. How much heat is required to melt 0.5 grams of ice at 0° C

1. Heat of vaporization of water is 540 cal/g

10g x 540 cal/g = 5400 cal

2. Heat of fusion of water is 80 cal/gram

(0.5 grams)(80 cal/gram) = 40 cal