Chem exam 1 study
Study Guide on Matter and Measurement
Properties of Solids, Liquids, and Gases
Solids: Have a definite shape and volume; particles are closely packed together and vibrate in fixed positions.
Liquids: Have a definite volume but take the shape of their container; particles are close but can move past one another.
Gases: Have neither definite shape nor volume; particles are far apart and move freely.
Types of Mixtures and Methods of Separation
Types of Mixtures:
Homogeneous Mixtures: Uniform composition throughout (e.g., saltwater).
Heterogeneous Mixtures: Composition is not uniform (e.g., salad).
Methods of Separation:
Filtration: Separating solids from liquids using a filter.
Distillation: Separating components of a mixture based on boiling points.
Chromatography: Separating substances based on their movement through a medium.
Significant Figures in Measurement and Calculations
Significant figures are the digits in a number that carry meaningful information about its precision. Rules include:
All non-zero digits are significant.
Any zeros between significant figures are also significant.
Leading zeros are not significant.
Trailing zeros in a number with a decimal are significant.
Physical vs. Chemical Properties and Reactions
Physical Properties: Can be observed without changing the substance (e.g., color, boiling point).
Chemical Properties: Can only be observed during a chemical reaction (e.g., flammability, reactivity).
Physical Reactions: Changes that do not alter the chemical composition (e.g., phase changes).
Chemical Reactions: Changes that produce new substances (e.g., rusting).
Intensive vs. Extensive Properties
Intensive Properties: Do not depend on the amount of substance (e.g., density, boiling point).
Extensive Properties: Depend on the amount of substance (e.g., mass, volume).
Precision vs. Accuracy
Precision: How close the measurements are to each other.
Accuracy: How close the measurements are to the true or accepted value.
Structure and Arrangement of an Atom
Atoms consist of protons (positive), neutrons (neutral), and electrons (negative).
Isotope structure refers to atoms with the same number of protons but different numbers of neutrons (e.g., Carbon-12, Carbon-14).
Wave/Particle Properties of Light
Light exhibits both wave-like and particle-like behavior (wave-particle duality).
It can behave as a wave (e.g., interference, diffraction) and as a particle (e.g., photons).
Basic Concept of Energy Quantization
Energy quantization refers to the idea that energy exists in discrete levels. Electrons in an atom can only exist at certain energy levels and absorb or emit energy when they transition between these levels.
Additional Study Guide for Advanced Concepts
Nuclear Reactions and Radioactive Decay
Balancing Nuclear Reactions: Understand how to represent the conservation of mass and charge in nuclear decay equations. Practice fill-in-the-blank and open-ended calculations.
Dimensional Analysis and Unit Conversions
Dimensional Analysis: Learn how to convert between different units using conversion factors. Be prepared to work with both numerator and denominator units, and apply exponents as needed.
Density Calculations
Density Calculations: Use the formula density (D) = mass (m) / volume (V) to solve for unknown variables such as mass or volume by rearranging the equation.
Isotopic Masses and Natural Abundance
Isotopic Mass: Calculate the average atomic mass of an element based on its isotopes. Understand how to determine the natural abundance of isotopes using familiar formulas.
Representing Light in Different Units
Understand how to express light in terms of:
Joules (energy)
Nanometers (wavelength)
Hertz (frequency)
Photoelectric Effect Calculations
Photoelectric Effect: Complete calculations to determine the energy of photons and assess whether photoelectrons will be emitted based on the work function of the material.
Energy Transitions in Hydrogen Atom
Bohr’s Equation: Learn how to use Bohr’s equation to calculate energy transitions within a hydrogen atom, particularly how to determine the energy of emitted or absorbed light during electron transition between energy levels.