Chem 141 Exam 1 Study Checklist and Key Concepts

Exam 1 Study Checklist

This checklist outlines the essential topics and skills required for success on Exam 1 in General Chemistry. It covers foundational concepts from the first chapters, including matter, measurement, atoms, and elements, as well as basic calculations and problem-solving strategies.

Chapter 1: Matter, Measurement & Problem Solving

Significant Figures and Calculations

• Significant Figures: Understand and apply the rules for determining significant figures in measurements and calculations.

• Calculations: Perform calculations involving significant figures, including addition, subtraction, multiplication, and division.

• Scientific Notation: Express numbers in scientific notation and perform calculations using scientific notation.

• Unit Conversions: Convert between units using dimensional analysis (factor-label method).

• SI Units: Know the base SI units for mass (kg), length (m), time (s), and amount (mol).

• Density: Calculate density using the formula: $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$

• Temperature Conversions: Convert between Celsius, Kelvin, and Fahrenheit. $T_{\text{K}} = T_{\text{C}} + 273.15$ $T_{\text{F}} = \frac{9}{5}T_{\text{C}} + 32$

Chapter 2: Atoms & Elements

Atomic Theory and Structure

• Classification of Matter: Distinguish between elements, compounds, and mixtures (homogeneous and heterogeneous).

• Law of Conservation of Mass: Matter is neither created nor destroyed in a chemical reaction.

• Law of Definite Proportions: A compound always contains the same elements in the same proportion by mass.

• Law of Multiple Proportions: When two elements form more than one compound, the ratios of the masses of the second element that combine with a fixed mass of the first element are ratios of small whole numbers.

• Atomic Theory: Understand Dalton’s atomic theory and its postulates.

• Subatomic Particles: Know the properties of protons, neutrons, and electrons (charge, mass, location).

• Atomic Number and Mass Number: Define and calculate atomic number (Z) and mass number (A).

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Elements and Symbols: Memorize the names and symbols of common elements.

• Periodic Table: Understand the organization of the periodic table and the significance of groups and periods.

• Historical Experiments: Be familiar with key experiments (e.g., Thomson’s cathode ray, Rutherford’s gold foil) and their contributions to atomic theory.

Chapter 3: Molecules and Compounds

Chemical Nomenclature and Formulas

• Chemical Formulas: Write and interpret chemical formulas for elements and compounds.

• Ions: Understand the formation of cations and anions, and the difference between them.

• Naming Compounds: Apply the rules for naming ionic and molecular compounds.

• Polyatomic Ions: Memorize the names, formulas, and charges of common polyatomic ions.

• Mole Concept: Use Avogadro’s number ($6.022 \times 10^{23}$) to convert between moles, particles, and mass.

• Molar Mass: Calculate the molar mass of compounds and use it in stoichiometric calculations.

Reference: Periodic Table and Constants

• A periodic table will be provided during the exam. Know how to use it to find atomic numbers, atomic masses, and element symbols.

• Be familiar with the following constants and conversions:

Constant/Conversion	Value
1 Å (angstrom)	$1 \times 10^{-10}$ m
1 nm (nanometer)	$1 \times 10^{-9}$ m
1 pm (picometer)	$1 \times 10^{-12}$ m
1 in (inch)	2.54 cm
1 cm3	1 mL
1 L	$1 \times 10^{3}$ mL

Additional info:

• Practice with multiple choice, short answer, and calculation-based questions is recommended.

• Review all lecture slides, homework, and textbook problems for comprehensive preparation.