Study Notes for CHMY-161: Introduction to Chemistry and Scientific Method

Course Introduction and Course Materials

Welcome to CHMY-161. The primary textbook for this course is General, Organic, and Biological Chemistry: Structures of Life, Sixth Edition by Timberlake. It is essential to utilize the sixth edition specifically. Students must maintain active engagement with the course Canvas site to access the syllabus and the detailed schedule of classes and assignments.

A Satirical Perspective on Education

To begin the semester, the instructor shares a cartoon titled "A Cartoon About Wising Up." The cartoon presents a satirical view of the education system, highlighting themes often encountered in school environments. It suggests that learning is frequently presented as having nothing to do with life, appearing passive and tedious. The cartoon posits that students are often expected to act only when bribed, tricked, or forced, and that the modern educational experience is designed to keep "tiny monsters" off the street until the age of 18. It warns that students may be viewed as merely "creeps fit only to take orders" where individual concerns count for nothing. The "quick way" to education involves recognizing that the goal is often simply to avoid trouble by doing what one is told and existing in a daze to be less unhappy. This serves as a humorous warning to avoid a passive approach to this specific course.

Professional Advice and the Nature of Chemistry

The instructor provides specific advice for success in CHMY-161. Chemistry is defined not just as a branch of science, but as a discipline involving the science of taking measurements and a practice of solving complex math problems. It is inherently an experimental science. Most importantly, chemistry is described as a "participation sport"; it requires active involvement rather than passive observation. Falling behind in this subject makes catching up extremely difficult. To assist students, free tutoring is available for those who need extra help.

Chapter 1: Chemistry in Our Lives

Chapter 1 serves as an introduction to how chemistry permeates everyday existence. Chemistry is the study of the composition, structure, properties, and reactions of matter. It is happening all around us every day. For example, antacid tablets undergo a chemical reaction the moment they are dropped into water.

Chemistry involves the development of new products and pharmaceuticals. Typical roles for professionals in this field include chemists working in laboratories to test new products and forensic scientists who work in crime laboratories. Forensic scientists analyze bodily fluids and tissue samples collected by crime scene investigators to solve crimes.

Case Study: Ibuprofen Oral Suspension

A practical example of chemistry in daily life is found in over-the-counter medications like CVS Pharmacy Children's Ibuprofen (Berry Flavor flavor). This product is a nonsteroidal anti-inflammatory drug (NSAID) designed to serve as a pain reliever and fever reducer for children aged 2 to 11 years. The medication is standardized at a concentration of $100\,mg$ per $5\,mL$ (one teaspoonful) and can last up to $8$ hours. It is formulated to be gluten-free and alcohol-free.

The active ingredient is ibuprofen ($100\,mg$ per $5\,mL$). The drug facts provide critical safety information, such as an allergy alert for those allergic to aspirin, symptoms of which include hives, facial swelling, asthma (wheezing), shock, skin reddening, rash, or blisters. The label also warns of potential stomach bleeding, particularly for children who have had stomach ulcers, take blood thinners or steroids, or take other NSAIDs like ibuprofen, naproxen, or aspirin.

Dosing is determined primarily by weight, and secondarily by age:

• Under 2 years: Ask a doctor

• $24\text{--}35\,lbs$ ($2\text{--}3$ years): $1\,tsp$ or $5\,mL$

• $36\text{--}47\,lbs$ ($4\text{--}5$ years): $1.5\,tsp$ or $7.5\,mL$

• $48\text{--}59\,lbs$ ($6\text{--}8$ years): $2\,tsp$ or $10\,mL$

• $60\text{--}71\,lbs$ ($9\text{--}10$ years): $2.5\,tsp$ or $12.5\,mL$

• $72\text{--}95\,lbs$ ($11$ years): $3\,tsp$ or $15\,mL$

Infants' concentrated drops contain a different concentration of $50\,mg$ per $1.25\,mL$. The dosing chart for infants is as follows:

• Under 6 months: Ask a doctor

• $12\text{--}17\,lbs$ ($6\text{--}11$ months): $1.25\,mL$

• $18\text{--}23\,lbs$ ($12\text{--}23$ months): $1.875\,mL$

Chemical Composition of Household Items

Many substances we use daily are complex combinations of chemicals. Toothpaste, for instance, contains various chemicals with specific functions:

• Calcium carbonate: Used as an abrasive to remove plaque.

• Sorbitol: Prevents loss of water and the hardening of the toothpaste.

• Sodium lauryl sulfate: Used to loosen plaque.

• Titanium dioxide: Makes toothpaste white and opaque.

• Triclosan: Inhibits bacteria that cause plaque and gum disease.

• Sodium fluorophosphate: Prevents cavities by strengthening tooth enamel with fluoride.

• Methyl salicylate: Provides a pleasant wintergreen flavor.

Other examples of chemicals in everyday items include Silicon dioxide ($SiO_2$) in glass, chemically treated water ($H_2O$), metal alloys, natural polymers, natural gas, and fertilizers or pesticides used in growing fruit. Glycerin (a skin protectant) and Silica Gel (a desiccant) are also common items involving specific chemical structures.

Section 1.2: The Scientific Method

The scientific method is a set of general principles that describes how a scientist thinks and investigates the world. It follows a specific cycle:

1. Observations: You observe a phenomenon (e.g., your friend has a new cat and you begin sneezing).

2. Hypothesis: You form a tentative explanation for the observations (e.g., "I am allergic to cats").

3. Experiments: You perform tests to validate the hypothesis (e.g., visiting other friends with cats to see if you sneeze).

4. Conclusion: Based on the results, you determine if the hypothesis is correct. If the results do not support the hypothesis, it must be modified and the cycle repeats.

Linus Pauling, a famous chemist, exemplifies scientific excellence, having won the Nobel Prize in chemistry in 1954.

Section 1.4: Key Math Skills for Chemistry

Success in chemistry requires proficiency in several mathematical areas. Studying in groups is recommended as a beneficial learning strategy for mastering these skills.

Percentages

To determine a percentage, divide the part by the total (whole) and multiply by $100\%$. For example, if there are 2 red balls in a total of 40 balls, the calculation is: $\frac{2}{40} \times 100\% = 5\%$ In a practical scenario, if you have an annual gross salary of $\$35,000$ and are in a $33\%$ income tax bracket, you must be able to calculate your net salary.

Solving Algebraic Equations

Chemistry often requires rearranging equations to solve for a specific variable. For example, to solve $2x + 8 = 14$:

1. Subtract $8$ from each side: $2x = 6$

2. Divide both sides by $2$: $x = 3$

In chemical gas laws, you might solve the equation $P_1 V_1 = P_2 V_2$ for $P_1$ by dividing both sides by $V_1$: $P_1 = \frac{P_2 V_2}{V_1}$

Interpreting Graphs

Graphs represent the relationship between an independent variable ($x$) and a dependent variable ($y$). By measuring pairs of $(x, y)$ data points, relationships can be visualized (e.g., as $x$ increases, $y$ also increases). Graphs are essential for predicting a $y$ value for any given $x$ value.

Scientific Notation

Scientific notation is used to express very large or very small numbers efficiently. It consists of three parts: a coefficient (which must be between 1 and 10), a power of 10, and a unit.

Large and Small Numbers

• Large Number Example: The distance $150\,m$ can be written as $1.5 \times 10^2\,m$. A positive power of 10 is used to express large numbers.

• Small Number Example: The volume $0.0075\,L$ can be written as $7.5 \times 10^{-3}\,L$. A negative power of 10 is used to express small numbers.

• Height of a human hair: $0.000,008\,m = 8 \times 10^{-6}\,m$

• Count of hairs: $100,000\text{ hairs} = 1 \times 10^5\text{ hairs}$

Converting Standard Numbers to Scientific Notation

• $2400\,m = 2.4 \times 10^3\,m$

• $0.00086\,g = 8.6 \times 10^{-4}\,g$

• $64,000\,m = 6.4 \times 10^4\,m$

• $0.021\,L = 2.1 \times 10^{-2}\,L$

Table of Standard Measurements and Scientific Notation

Calculator Procedures

To enter scientific notation into a calculator, use the following procedures:

• To enter $4 \times 10^6$: Press 4, then EE or EXP, then 6. The display may read 4 06, 406, or 4E06.

• To enter $2.5 \times 10^{-4}$: Press 2.5, then EE or EXP, then the +/- key, then 4. The display may read 2.5-04, 2.5-04, or 2.5E-04.

Homework

Homework for Chapter 1 is available on the Canvas site and should be checked immediately to ensure compliance with the schedule.