General Chemistry CHE 101 Quiz Part I

General Chemistry (CHE 101)

• General Chemistry course, course code CHE 101

Topics Breakdown (Part I)

• Chemistry: The Study of Change (Chapter 1)
• Atoms, Molecules, and Ions (Chapter 2)
• Quantum Theory and the Electronic Structure of Atoms (Chapter 7)
• Periodic Relationships Among the Elements (Chapter 8)

Further Details: Topic Breakdown

• Chemistry involves the study of what happens when electron clouds of different substances interact.
• The course will explore different types of bonding based on examples of atoms colliding with other substances.
• The important chapters from the first part are Chapter 1, 2, 7, and 8.
• These chapters cover the initial concepts of the subject.

Chapter 1: Chemistry: The Study of Change

• Chemistry is the study of change.
• Chemistry focuses on what happens when the electron cloud of one substance encounters the electron cloud of another.

General Atomic and Molecular Properties

• Atoms interact by transferring or sharing electrons.
• The transfer of electrons results in an ionic bond.
• The sharing of electrons creates a covalent bond.
• The illustration shows sodium (Na) and chlorine (Cl) colliding.
• Sodium gives an electron to chlorine.
• This produces a negatively charged chlorine ion (Cl-) and a positively charged sodium ion (Na+).
• The ions form an ionic bond in sodium chloride (NaCl).

Covalent Bonding Example

• Hydrogen (H) atoms collide and share electrons.
• This creates a covalent bond in a hydrogen molecule (H2).
• The atoms share one pair of electrons to complete their valence shells.

Molecular Interactions and Reactions

• Different molecular interactions and reactions might occur when two atoms or molecules collide.

General Science Concepts

• Matter has mass and occupies space.
• Energy is the "normal stuff" in the universe outside of matter.
• Matter and energy are related by E = mc²
• Modern astrophysics shows that matter and energy are about 5% of the universe ; Dark matter and Dark energy take up the rest.

Chemical Changes

• Chemical changes involve breaking chemical bonds, rearranging atoms, and forming new chemical bonds.
• An example of a chemical change is propane burning in oxygen; it produces carbon dioxide and water.
• Chemical equation, example, C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

Physical Changes

• Physical changes relate to changes in state, like solid to liquid to gas, and dissolving processes.
• Examples - Water freezes to ice, ice melts to water, sugar dissolves in water, water evaporates and leaves behind the sugar.

A Burning Candle

• A burning candle shows both physical and chemical changes.
• The heat from the flame changes wax from solid to gaseous form.
• Then, the converted gaseous wax burns in the air with oxygen to create carbon dioxide and water.

Phases of Fire

• Diagram displays the different phases of a candle's burning process.
• A fuel vapor cloud is formed from the melting and pyrolysis of the solid wax.
• Heating from the flame provides energy for breaking the bonds in the fuel and oxygen to release rearrangements.
• A reaction zone is created where fuel vapors and oxygen come into contact to form CO₂ and H₂O, then dissipates in turbulent mixing.

Numbers in Chemistry

• Numbers in chemistry are often either too big or too small for writing in their decimal form.
• Use exponential notation (scientific notation).
• Example: The number of copper atoms in a pre-1982 penny is 29,500,000,000,000,000,000,000 atoms.
• Expressed as 2.95 x 10²² atoms.

Weight of a single copper atom

• The weight of a single copper atom is a very small number.
• Example: 0.000 000 000 000 000 000 000 000 23 lbs.
• Expressed as 2.3 x 10⁻²⁵ lbs

Significant Figures Practice

• Significant figures can be used when doing calculations with big or small numbers.
• Example: 0.0003007 has 4 significant figures.
• Example, 15.00 has 4 significant figures. Example: 1200 has 2 significant figures.

Calculations with Scientific Notation

• Follow the rules in your textbook when multiplying and dividing with exponential notation.
• The calculator should be set to do so.

Units of Measurement

• Units of Measurement consist of two components: (a) A number and (b) A unit.

Unit Systems

• Metric (SI), English

Basic Metric Systems

• Length-meters (m)
• Volume-cubic meters (m³), or liters (L) or cm³ (cc's).
• Mass-grams (g)
• Time-seconds (s)

Unit Prefixes

• Units may be too big or small to write conveniently.
• Examples include the units-giga (G), mega (M), kilo (k), deci (d), centi (c), milli (m), micro (μ), nano (n), pico (p).

Temperature Systems

• Celsius (or Centigrade), Kelvin, Fahrenheit

Celsius vs. Kelvin

• Both use the same sized degree.
• Celsius goes from 0 to 100
• Kelvin goes from 273 to 373

Fahrenheit Scale

• Has 180 steps between freezing and boiling.
• 1° Celsius = 1.8° Fahrenheit
• 32 °F = 0° C

Celsius/Kelvin Conversions

• K = °C + 273
• °C = K - 273

Celsius/Fahrenheit Conversions

• °F = (1.8 x °C) + 32
• (°F - 32) / 1.8 = °C

Sample Calculations

• Calculations using conversions, including temperature conversions (Fahrenheit to Celsius), and using the factor-label method.

General Summary of the Topics

• Chapters related to fundamental chemical concepts and calculations, unit conversions, and significant figures are all part of General Chemistry 101, which is a comprehensive introduction to chemistry.