CHEM 151 Session 1 slides

Course Introduction

CHEM151 IN General ChemistryInstructor: Dr. Garrett Davis, Ph.D.Fall Semester 2023, August 28th

Reasons for Taking Chemistry

Reflection Questions:

• Previous experience in Chemistry or Science?

• Concerns or fears about the class (math, concepts, workload)?

• Reasons for taking the class (required for major/degree, genuine interest, career aspirations)?

• Which topics are you particularly excited to learn about?

• What are your educational and career goals related to chemistry or science?

Today's Topics and Learning Objectives

Overview:

• Definition of Chemistry and its applications across various fields.

• Understanding the Scientific Method, a systematic process for investigating natural phenomena.

• An introduction to the three primary states of matter: solids, liquids, and gases, along with a brief mention of plasma as a fourth state.

• Focus on measurements: understanding the metric system and the SI (International System of Units).

• Dimensional analysis and unit conversions, critical for accurate scientific calculations.

Definition of Chemistry

Chemistry is defined as the study of:

• The composition, properties, and interactions of matter;

• The identification of substances based on their unique characteristics;

• Investigating how substances interact, combine, and transform into new substances through chemical reactions.

Fields Related to Chemistry

Chemistry's Interconnections:

• Chemistry is fundamentally linked to various disciplines such as:

  • Mathematics: for quantitative analysis and problem-solving;

  • Medicine: crucial in drug development and understanding biochemical processes;

  • Biology: essential for understanding cellular processes and biochemistry;

  • Physics: provides insight into the behavior of matter at both macroscopic and microscopic levels.

Diverse Applications of Chemistry

Chemistry impacts numerous fields, including but not limited to:

• Food Science: studying the chemical processes in food production and preservation;

• Geology: understanding the composition and processes of earth materials;

• Earth Sciences: investigating atmospheric and geological changes;

• Environmental Science: analyzing pollutant interactions and ecosystem impacts;

• Biochemistry: exploring the chemical processes within and related to living organisms;

• Chemical Engineering: designing processes to create chemicals and materials.

Importance of Chemistry

Group Discussion Prompt:

• Share four ways Chemistry is significant in society or personal lives, giving examples such as:

  • Drug research leading to breakthroughs in health;

  • Development of sustainable materials;

  • Innovation in agricultural chemicals to enhance food production;

  • Analysis of environmental pollutants to safeguard public health.

A Brief History of Chemistry

Introduction to significant historical moments in chemistry:

• Important discoveries such as the periodic table, atomic theory and their evolution;

• Concepts of earth's layers and the atmosphere's evolution over time.

RNA and DNA Formation

Explores the progression of life beginning with simple chemical elements leading to RNA formation and diversification, which is fundamental to all biological processes.

Historical Figures in Chemistry

Recognizing notable chemists:

• Robert Hooke: known for Hooke's law;

• Antonie van Leeuwenhoek: father of microbiology;

• Louis Pasteur: pioneer in microbiology and vaccination;

• Robert Koch: founder of modern bacteriology;

• Joseph Lister: contributed to antiseptic surgical techniques.

Further Importance of Chemistry

Delving deeper into Chemistry's relevance in various fields:

• Medicine: drug formulation and medical diagnostics;

• Engineering: materials science and structural integrity;

• Nutrition: understanding food composition and metabolism;

• Energy: studying chemical processes for energy production and storage.

Group Discussions:

Encouraging analysis and conversations around chemistry's societal impact and responsibilities.

The Scientific Method - Vocabulary

Key terms in scientific investigation:

• Observation: gathering information through the senses;

• Hypothesis: an educated guess based on observations.

The Scientific Method - Experimentation

Definition:

• A controlled procedure used to test a hypothesis by identifying cause-and-effect relationships in systematic ways.

Variables in Experiments

Understanding the concept of variables:

• Independent Variable: the variable that is manipulated in the experiment;

• Dependent Variable: the outcomes that are measured or observed.

Theories and Laws in Science

Key Concepts:

• Scientific Theory: a well-substantiated explanation based on a body of evidence;

• Scientific Law: describes consistent natural relationships without providing explanations.

Examples:

• Newton's Law of Universal Gravitation (law);

• Atomic Theory (theory).

Key Differences

• Theories provide a deeper understanding of phenomena, while laws describe observable relationships without explaining why they exist.

The Scientific Method Process

Steps:

1. Observation - Identifying the nature of a phenomenon.

2. Hypothesis Formation - Proposing a potential explanation.

3. Experimentation - Conducting controlled experiments to test the hypothesis.

4. Distinction of Laws and Theories - Understanding their roles in science.

Macroscopic vs Microscopic

Definitions:

• Macroscopic: refers to large-scale objects observable by human senses, such as chairs, trees, etc.

• Microscopic: pertains to small particles and molecular interactions that affect larger systems at the molecular level (e.g., atoms, molecules).

States of Matter

Matter is defined as anything that occupies space and has mass.

Four States of Matter:

1. Solid - Fixed shape and volume; closely packed particles.

2. Liquid - Fixed volume but no definite shape; particles are close but can flow.

3. Gas - Neither fixed shape nor volume; particles are far apart and move freely.

4. Plasma - A state exhibiting highly energized particles found in high-energy environments like stars.

Measurements and Classifying Matter

Metric Measurements:

• Mass represented in grams, weight as the force of gravity acting on an object.

• Pure Substances: Elements that cannot be broken down into simpler substances; Compounds are formed when two or more elements chemically combine.

Mixtures and Their Classifications

Mixtures:

• Can be classified as homogeneous (uniform composition throughout) or heterogeneous (varying composition).

Atoms, Molecules, and Compounds

Distinctions:

• Atoms: the smallest unit of elements.

• Molecules: made up of two or more atoms bonded together.

• Compounds: formed when two or more different elements chemically connect.

Properties of Matter

Types of Properties:

• Physical Properties: observable characteristics that do not change the chemical identity of the substance.

• Chemical Properties: describes how a substance can change into another substance through chemical reactions.

Extensive vs Intensive Properties

Definitions:

• Extensive Properties: depend on the amount of substance present (e.g., mass, volume).

• Intensive Properties: do not depend on the amount of substance (e.g., density, boiling point).

SI Measurements Usages

Importance:

• Including units in measurements is critical for clarity and accuracy; standard SI units for key measurements include:

  • Length: meters;

  • Mass: kilograms;

  • Temperature: Kelvin (K) and Celsius (°C).

Volume and Density

Definitions:

• Density is defined as mass per unit volume; it is a crucial property for identifying substances and understanding buoyancy.

• Formulas for calculating density (D = mass/volume) are presented with sample problems.

Dimensional Analysis and Unit Conversions

• Demonstrated unit conversion through various practical examples, emphasizing the importance of correct unit application in calculations.

Significant Figures in Measurements

Definitions:

• Significant figures account for the precision of measurements.

General Rules:

1. Non-zero digits are always significant.

2. Any zeros between significant digits are also significant.

3. Leading zeros in a number are not significant.

4. Trailing zeros in a decimal number are significant.

Practice Problems and Agenda

• Structured examples of calculating significant figures and performing calculations with appropriate precision are provided for practice.