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General Chemistry: Matter, Measurement, and Problem Solving

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Termini in questo insieme (33)

  • What determines the properties of matter?
    The properties of matter are determined by the properties of molecules and atoms.
  • What are atoms and molecules in relation to matter?
    Atoms are submicroscopic particles that are the fundamental building blocks of matter; molecules are groups of atoms bonded in specific arrangements.
  • How do graphite and diamond differ despite both being carbon?
    Graphite atoms are arranged in sheets, while diamond atoms form a three-dimensional structure, leading to different properties.
  • What is the scientific method?
    A process for understanding nature by observation, hypothesis formulation, experimentation, and development of laws and theories.
  • Define a scientific hypothesis.
    A tentative explanation of observations that is falsifiable and can be tested by experiments.
  • What is a scientific law?
    A brief statement summarizing past observations and predicting future ones, such as the law of conservation of mass.
  • What is a scientific theory?
    A well-established model explaining why nature behaves as it does, validated by experiments but never conclusively proven.
  • How is matter classified by state?
    Matter exists as solid, liquid, or gas, distinguished by particle arrangement and movement.
  • Describe the characteristics of solid matter.
    Atoms or molecules are closely packed in fixed locations, vibrating but not moving past each other, giving solids fixed volume and shape.
  • What distinguishes crystalline solids from amorphous solids?
    Crystalline solids have long-range repeating atomic order; amorphous solids lack this order.
  • Describe liquid matter properties.
    Particles are close but free to move relative to each other; liquids have fixed volume but take the shape of their container.
  • What are the properties of gaseous matter?
    Particles have large spaces between them, move freely, and gases are compressible.
  • How is matter classified by composition?
    Matter is classified as pure substances (elements or compounds) or mixtures (heterogeneous or homogeneous).
  • Define an element and a compound.
    An element cannot be chemically broken down; a compound consists of two or more elements in fixed proportions.
  • What is the difference between heterogeneous and homogeneous mixtures?
    Heterogeneous mixtures have variable composition in different regions; homogeneous mixtures have uniform composition throughout.
  • Name three methods to separate mixtures.
    Decanting, distillation, and filtration exploit physical or chemical property differences to separate mixture components.
  • What is a physical change?
    A change altering only the state or appearance of a substance without changing its composition.
  • What is a chemical change?
    A change that alters the composition of matter by rearranging atoms to form new substances.
  • Differentiate physical and chemical properties.
    Physical properties can be observed without changing composition; chemical properties require a chemical change to be observed.
  • What is energy in chemistry?
    The capacity to do work, including kinetic energy (motion), potential energy (position/composition), and thermal energy (temperature-related kinetic energy).
  • State the law of conservation of energy.
    Energy is neither created nor destroyed in physical or chemical changes.
  • What is the SI unit of length and how is it defined?
    The meter (m), defined as the distance light travels in a vacuum in 1/299,792,458 of a second.
  • What is the SI unit of mass?
    The kilogram (kg), which is 1000 grams; mass measures the quantity of matter.
  • How is temperature measured in SI units?
    Temperature is measured in kelvin (K), an absolute scale where 0 K is absolute zero.
  • What are SI prefix multipliers?
    Prefixes that change unit values by powers of ten, such as kilo (10^3), milli (10^-3), and micro (10^-6).
  • Define density and its units.
    Density is mass per unit volume, typically expressed in grams per cubic centimeter (g/cm³).
  • What is the difference between intensive and extensive properties?
    Intensive properties do not depend on amount (e.g., density); extensive properties depend on amount (e.g., mass).
  • What are significant figures?
    Digits in a measurement that reflect its precision, including all certain digits plus one estimated digit.
  • Rules for counting significant figures?
    All nonzero digits and interior zeros are significant; leading zeros are not; trailing zeros depend on decimal placement.
  • How to apply significant figures in multiplication/division?
    Result carries the same number of significant figures as the factor with the fewest significant figures.
  • How to apply significant figures in addition/subtraction?
    Result carries the same number of decimal places as the quantity with the fewest decimal places.
  • Difference between accuracy and precision?
    Accuracy is closeness to the true value; precision is consistency among repeated measurements.
  • What is dimensional analysis?
    A problem-solving method using units to guide calculations and conversions.