Chemistry 2

Class Opening and Administrative Reminders

The class began with a prayer by Gaston, expressing gratitude and hope for learning and rectifying mistakes, especially concerning homework. Following the prayer, administrative announcements were made. Students were informed that quiz results from the previous week, indicating correct and incorrect answers, had been emailed. Nicholas was asked to provide his email address as it was not in the system to receive his quiz results. It was emphasized that reviewing incorrect answers is crucial for growth and preparation for upcoming assessments. The instructor outlined the evaluation structure: regular weekly quizzes, unit tests (after completing each unit), a mid-trimester test covering all material from day one, and a final trimester test. Students were encouraged to ask questions about anything they do not understand to continuously build their knowledge base.

Regarding assignments, the link for last week's Monday assignment was fixed. Students who had not emailed their answers could now upload them directly. Those who had emailed did not need to upload but could if they wished. Additionally, a reading assignment was given yesterday, and today's class included a quiz based on it. This particular quiz does not count towards the overall grade; instead, successful completion earns bonus points that will be added to the weekly quiz score, providing an incentive for reading and preparation. It was stressed that this reading check must be completed independently without external help or materials. This structure of offering reading check quizzes for bonus points will continue for all future reading assignments.

Introduction to Atomic Theory

The main topic for the day was the history of the atomic theory. Lenny initiated the discussion by recalling that the concept originated around 400 BC with the Greek philosopher Democritus, who observed that everything is made of "very, very tiny particles." This initial idea then evolved as other scientists and philosophers contributed their insights.

Understanding "Theory" in Science

Before delving into the atomic theory, the class clarified the definition of a "theory." Kimmy correctly defined a theory as a hypothesis that has been tested through experiments by multiple scientists, with the hypothesis consistently remaining true. This means that the atomic theory, like any scientific theory, began as a hypothesis, underwent rigorous testing, and has been consistently supported by evidence, distinguishing it from an "atomic law."

Early Greek Philosophical Atomic Ideas

Aristotle's View

The concept of atoms began with the Greek philosopher Aristotle, a student of Plato and Socrates. Aristotle proposed the idea of a universe where matter is infinitely divisible. This meant that any substance, defined as "anything that has mass and takes up space," could be divided an infinite number of times into smaller and smaller entities. Aristotle believed that all matter was composed of the same fundamental particles (not yet called atoms). The differences observed in various materials, such as salt versus sugar or sand versus clay, were attributed to "varying degrees of moisture, dryness, heat, and cold" within these substances, rather than fundamental differences in their composition.

Democritus's Counter-Argument

Later, another Greek philosopher, Democritus, presented an opposing view. He concluded that matter is made of "tiny particles and empty space." These tiny, indivisible particles were called atomos, a Greek word meaning "indivisible." In contrast to Aristotle, Democritus posited that "different materials are made of different atoms." For example, he would argue that water and alcohol differ not because of varying degrees of moisture, but because they are composed of different types of atoms. Based on modern scientific understanding, Democritus's view was more accurate. For instance, alcohol ( $C<em>2H</em>6O$ ) and water ( $H_2O$ ) are distinct compounds due to their different atomic compositions and ratios of elements.

Greek Hypothesis Testing: A Historical Anomaly

An intriguing point of discussion was how Greek philosophers tested their hypotheses. The answer is: they didn't, in the modern sense. The scientific method, crucial for hypothesis testing, was developed much later. Greek society was structured with two primary classes: the philosophers (upper class) and the plebeians (lower class).

Philosophers considered manual labor and physical experimentation to be "beneath them," reserving it for the lower classes. Their work was purely theoretical and cerebral.
Plebeians were "not allowed to use their minds for upper level thinking," meaning they were restricted from engaging in critical thinking or problem-solving. They performed the manual tasks.

This societal division created a handicap for scientific progress, as both hands-on experimentation and intellectual analysis are necessary for effective scientific inquiry. The instructor drew a parallel to modern society, comparing the doctor (often perceived as the "brain," performing less hands-on work) and the nurse (often performing more hands-on, direct patient care, sometimes seen as "beneath" doctors).

Reflection on "Upper Level Thinking"

During a short break, the concept of "upper level thinking" was further explored. It was defined as engaging in problem-solving skills and critical thinking skills. The class reflected on whether modern society, despite its advancements, truly values or consistently engages in deep thought, often preferring ease and entertainment over intellectual challenges. Examples like the use of calculators instead of memorizing multiplication tables, or relying on AI for information, were cited as evidence that perhaps the inclination to avoid "upper level thinking" persists or has even worsened. This led to a brief philosophical and theological connection, referencing biblical warnings about blind following (Revelation 13:3) and the importance of independent thought.

The Evolution of Atomic Understanding Post-Greeks

For over 2000 years after Aristotle, his theories were largely accepted without challenge, highlighting the danger of blindly accepting authority. It wasn't until much later that people began to rethink these ideas.

The Era of Alchemists

Between the Greek philosophers and later scientists, the alchemists emerged. They were obsessed with trying to create gold from common materials like charcoal and coal. Although they "failed tremendously" in their primary goal, their efforts were not entirely in vain. The alchemists were instrumental in establishing "many experimental techniques and systems of notation and symbols," which were foundational for the development of modern chemistry.

Challengers to Aristotle's Views

As the scientific method slowly began to develop, new figures emerged who challenged Aristotle's long-held views:

Sir Isaac Newton: Known for his work on gravity, Newton was also a deep student of prophecy and viewed the study of science as a means of understanding God.
Robert Boyle: Also a prominent scientist with a strong Christian background, Boyle similarly challenged existing ideas about matter.
Antoine Lavoisier: A French chemist, considered the "father of modern chemistry." He is credited with recognizing and naming "oxygen and hydrogen" and determining oxygen's crucial "role in combustion." His work laid groundwork for quantitative chemistry.

John Dalton and the Modern Atomic Theory

The most significant challenger to previous atomic ideas was John Dalton, an Englishman. He is renowned for proposing the modern atomic theory and also conducted research on hereditary color blindness. Dalton also established the law of multiple proportions.

Dalton's Atomic Theory: Four Key Assumptions

Dalton's atomic theory is based on four fundamental assumptions:

All matter is made of atoms. This foundational assumption remains a core belief in chemistry.
Atoms of the same element are identical. This means that all atoms of a specific element (e.g., all oxygen atoms, regardless of their location) possess the same properties, including the same number of protons and atomic mass.
Atoms of different elements are different. This logically follows from the second assumption; hydrogen atoms and oxygen atoms, for example, are not the same.
Atoms unite in simple ratios to form compounds. This principle explains that atoms combine in specific, fixed proportions to create compounds. For instance, two hydrogen atoms ( $2H$ ) combine with one oxygen atom ( $1O$ ) to form water ( $H<em>2O$ ). In contrast, two hydrogen atoms ( $2H$ ) combining with two oxygen atoms ( $2O$ ) form hydrogen peroxide ( $H</em>2O_2$ ), a different compound entirely, used as an antiseptic. This highlights that the ratio of combining atoms determines the resulting compound. The lecture briefly touched upon electrolytes (atoms with charges, or ions) using the example of Gatorade, which infuses water with these charged atoms.

Modifications to Dalton's Theory

Despite its immense advancement in science, Dalton's atomic theory was not without flaws and has since been modified. As Peyton noted, theories are not static and can be changed with new evidence and information, unlike scientific laws which are considered fixed and immutable.

Here are the key mistakes and subsequent modifications:

Atoms are not indivisible: Dalton's term "atom" (from atomos, meaning indivisible) became a misnomer. We now know that atoms are not the smallest fundamental particles; they are composed of subatomic particles (protons, neutrons, electrons).
Atoms of the same element are not completely identical: Dalton posited that all atoms of the same element are identical. However, the discovery of isotopes disproved this. Isotopes are "atoms of the same element with the same number of protons but different number of neutrons." For example, while typical carbon has 6 protons and 6 neutrons, there are isotopes like Carbon-13 (6 protons, 7 neutrons) and Carbon-14 (6 protons, 8 neutrons). These variations in neutron count mean they are not exactly identical in mass.

The discussion then briefly touched upon the concept of elements being "created." It was clarified that when scientists discuss elements not being created, they are referring to human capabilities, not divine creation. The existence of synthesized elements on the periodic table was mentioned, providing a preview for future discussions on how these elements were discovered and the experimental methods used.

All students were encouraged to take meticulous notes and remain mentally engaged, as the difficulty of quizzes indicates the importance of focused participation in class. The lecture concluded, with a plan to distribute the PowerPoint slides as a supplement to the textbook reading and to delve deeper into experimental discoveries in the next session.