ILU- Describing Matter

*note this is most likely not everything* Elements (including diatomics), Compounds and Mixtures, Homogeneous vs. Heterogeneous, Solutions vs. Colloids vs. Suspensions, Tyndall Effect,Intensive Properties vs. Extensive Properties Qualitative Data vs. Quantitative Data, solid, liquid, gas (and vapor), plasma, Physical and Chemical Changes, Physical and Chemical Separations, Law of Conservation, LABS INFO: Paper Chromatography, chemical reactions/equations NOT ADDED YET: Analyzing particle level diagrams, images of samples/ laboratory steps/results

Pure substances

Uniform, fixed composition & properties, CANNOT be broken down by physical separations

Particle size from smallest to largest for colloid, solution, and suspension

1. Solution

2. Colloid

3. Suspension

Physical separations

Separation of a mixture into pure substances that DOES NOT change the chemical composition —> all materials that make up the mixture are available after separation

Chemical separations

Separations of substances that ALTERS CHEMICAL COMPOSITION (bonds formed or broken)

Monatomic

A molecule with only one atom (and remains stable)

Diatomic

A molecule with two atoms (contains a chemical bond)

He, Ne, Ar

Examples of monatomic molecules

O₂, N₂

Examples of diatomic molecules

Compounds (aka formula units or molecules depending on how they chemically combine)

Substance containing more than one atom, contains a chemical bond, CHONPS are 6 main atoms that things are made of

Homogenous mixture

A mixture that is evenly distributed (ie. coffee, wine, blood)

Heterogenous mixture

A mixture that is NOT evenly distributed (ie. water and oil, sandwich)

Electrolysis

use electricity to decompose a substance

Tyndall effect

The phenomenon happens when light passes through a small particle or liquid

Solutions

• Homogenous

• Smallest particles

• Transparent —> completely allows light to pass through

Colloids

• Homogenous

• Exhibits Tyndall effect (light passes through un the form of a beam due to light colliding with larger sized particles)

• Particles will NOT “settle out”

• ie. Jello, fog, milk

Suspensions

• Heterogeneous

• Biggest particles

• Particles can be filtered or “settle out”

• ie. Muddy water

Extensive properties

Properties that DEPEND on the sample size

• mass, volume

Intensive properties

Properties that ARE NOT dependent on sample size —> considered “constant” within the range of standard chemisty practices

• density, melting point, etc.

Physical properties

Quality or condition of a substance that can be observed or measured WITHOUT changing the substances composition

Chemical properties

Quality or condition of a substance that CANNOT be observed or measured without changing the substances composition (undergoing a chemical reaction)

Color, state of matter, boiling point, melting point, conductivity, magnetic

Examples of physical properties

Rust, corrosive, flammability, toxicity, combustion, reaction with water

Examples of chemical properties

Physical changes

• Changes that DO NOT alter chemical composition of the substance

• CAN be irreversible

Chemical changes

• Changes that chemically alter the composition of the substance

• Completely new substances with new properties are formed

• Synonymous w/ chemical reactions

Changes of state/phase, dissolving, cutting, tearing, grinding, reshaping, etc.

Examples of physical changes

Burning, scorching, cooking, fermenting, decomposing

Examples of chemical changes

Delta

Represents change

Evidence of chemical change

*not always a sign of chemical change

• Change in temp*

• Change in color*

• Evolution/formation of gas (effervescence)

• Production of light

• Production of precipitate

Law of conservation

mass/energy/matter cannot be created or destroyed during a normal chemical reaction

Qualitative

description, quality > quantity

Quantitative

Measurements, quantity

How do substances change state of matter

What type of mixture is this

Solution

What type of mixture is this

Colloid

What type of mixture is this

Suspension

E or I: Density

Intensive

E or I: Mass

Extensive

E or I: Melting point

Intensive

E or I: Volume

Extensive

Pc or Cc: cutting

Physical change

Pc or Cc: burning

Chemical change

Pc or Cc: cooking

Chemical change

Pc or Cc: dissolving

Physical change

Solid

Fixed shape & fixed volume

Liquid

Variable shape & fixed volume

Gas

Variable shape & variable volume

Vapor (related to gas)

When the substance is typically liquid or solid @ room temp

Plasma

• Variable shape & volume

• HIGH energy excited and ejects electrons

How to analyze paper chromatography

The results of paper chromatography can be analyzed and interpreted by visualizing the separated components on the paper and measuring the distance traveled by each component. The distance traveled can be compared to a known standard to identify the components.

Balance this equation:

C₂H₆O + _O₂ —> _CO₂ + _H₂O

C₂H₆O + 3O₂ —> 2CO₂ + 3H₂O