General Chemistry I

What you will learn

• Use units and significant figures to communicate measurements.
• Describe atomic structure and periodic patterns.
• Connect chemical formulas and bonding to substances' properties.
• Balance reactions and calculate amounts of reactants and products.
• Apply introductory ideas about gases and energy changes.

Common challenges

• A faster return to familiar topics

  College chemistry may revisit high school ideas quickly and in greater depth. Review before class and solve problems regularly instead of waiting for an exam.

• Multi-step calculations

  Write the known amount, target unit, and conversion path before calculating. Keep units on every line so you can catch a wrong setup.

• Switching between scales

  Draw particle diagrams beside formulas and observations. A balanced equation describes particle ratios, not just numbers on a page.

• Lecture and laboratory deadlines

  If a lab is included or paired with the course, plan for preparation and reports as well as class study. Follow the instructor's safety procedures exactly.

Key concepts

Atomic structure

Protons and neutrons are in the nucleus, while electrons occupy the surrounding space. Proton count determines the element.

Periodic patterns

The periodic table organizes elements by atomic number. Electron arrangements help explain recurring patterns in bonding and properties.

Chemical bonding

Bonding involves electrical interactions among nuclei and electrons. Introductory models distinguish electron sharing in covalent bonds from attraction between ions in ionic substances.

Mole

A mole is a counting unit containing exactly 6.02214076 × 10²³ specified entities. Molar mass connects this particle count to measurable mass.

Stoichiometry

Balanced equations give ratios used to calculate reactant and product amounts. The limiting reactant sets the maximum possible amount of product.

Energy changes

Chemical and physical changes transfer energy between a system and its surroundings. An exothermic process releases heat from the system.

How to prepare

• Review scientific notation, ratios, and rearranging algebraic equations.
• Practice converting units using conversion factors.
• Review element symbols, atomic number, and common ion charges.
• Check the course's calculator, laboratory, and safety-equipment instructions before classes start.

Study habits that help

• Carry units through every calculation and check whether the final unit matches the question.
• Draw particles to explain what an equation represents.
• Practice a mixed set of mole, mass, and reaction-ratio problems.
• Before a lab, identify the question, hazards, procedure, and data you need to record.

What to expect

Typical workload

Heavy

Time outside class

Typically about 8–12 hours outside scheduled class and lab each week for a lecture-and-lab combination; college and instructor requirements vary. A general college rule of thumb is about 2–3 study hours outside class for each hour in class, with lab preparation and reports adding time.

Pace

Units build quickly from measurements and atoms to reactions, calculations, and energy.

How it is usually graded

Courses typically use exams, quizzes, and problem sets; an associated lab may also grade preparation, safe technique, data analysis, and reports.

Skills that help

• Algebra and unit conversions
• Particle-level reasoning
• Careful measurement
• Scientific explanation

What teachers usually expect

• Show units and reasoning in calculations.
• Prepare for class and any laboratory before arriving.
• Report observations honestly and follow laboratory safety directions.

Before you start

• Colleges commonly expect algebra readiness and may require high school chemistry, a preparatory chemistry course, or placement.
• A laboratory may be required as a corequisite or separate enrollment; prerequisites differ by college, so check the college catalog.

These are general descriptions of a typical course. Workload, pace and prerequisites differ by school and instructor, so check with your counselor, advisor or the course catalog.

How it connects to majors

• Chemistry
• Chemical engineering
• Biochemistry
• Environmental science
• Health professions

Flashcards

Practice questions

Vocabulary

Atomic number

The number of protons in an atom's nucleus.

Isotope

One of the forms of an element differing in neutron count.

Ion

An atom or group of atoms with a net electric charge.

Mole

The amount containing exactly 6.02214076 × 10²³ specified entities.

Molar mass

The mass of one mole of a substance.

Stoichiometry

Calculation of chemical amounts using balanced reaction ratios.

Limiting reactant

The reactant that determines the theoretical maximum product amount.

Molarity

Moles of solute per liter of solution.