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General Chemistry: Introduction to Matter, Measurement, and Energy

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Termini in questo insieme (23)

  • What is chemistry?

    Chemistry is the study of matter, its properties, and the changes it undergoes.

  • What are the three states of matter?

    The three states of matter are solid, liquid, and gas.

  • Define a substance in chemistry.

    A substance has distinct properties and a composition that does not vary from sample to sample.

  • Difference between an element and a compound.

    An element cannot be decomposed into simpler substances, while a compound can be decomposed because it contains two or more elements.

  • What are atoms and molecules?

    Atoms are the building blocks of matter; molecules are groups of atoms bonded together.

  • How are elements represented in chemistry?

    Elements are represented by symbols, usually one or two letters, with the first letter capitalized.

  • What is the Law of Constant Composition?

    The Law of Constant Composition states that a compound always contains the same relative number of atoms of each element.

  • What is a mixture?

    A mixture contains two or more substances physically combined and can be homogeneous (uniform composition) or heterogeneous (non-uniform).

  • How can matter be classified?

    Matter can be classified as element, compound, homogeneous mixture, or heterogeneous mixture.

  • What is the difference between physical and chemical properties?

    Physical properties can be observed without changing the substance; chemical properties can only be observed when the substance changes into another substance.

  • Define intensive and extensive properties.

    Intensive properties do not depend on the amount of substance (e.g., density), while extensive properties depend on the amount (e.g., mass).

  • What is a physical change?

    A physical change alters the form of a substance but not its composition, such as changes in state.

  • What is a chemical change?

    A chemical change results in the formation of new substances, such as combustion or oxidation.

  • Name three methods to separate mixtures.

    Mixtures can be separated by filtration, distillation, and chromatography.

  • What is energy in chemistry?

    Energy is the capacity to do work or transfer heat.

  • Define kinetic and potential energy.

    Kinetic energy is energy of motion; potential energy is stored energy based on position.

  • What are SI base units for length, mass, and temperature?

    Length: meter (m), Mass: kilogram (kg), Temperature: kelvin (K).

  • What is the relationship between Celsius and Kelvin scales?

    \(K = ^\circ C + 273.15\)

  • What is density and its common units?

    Density is mass divided by volume, commonly expressed in g/cm³ or g/mL.

  • What are significant figures?

    Significant figures are all the digits in a measurement, including the uncertain last digit.

  • Rules for determining significant figures?

    1. All nonzero digits are significant.
    2. Zeros between nonzero digits are significant.
    3. Leading zeros are not significant.
    4. Trailing zeros are significant if after a decimal point.

  • How to apply significant figures in calculations?

    For addition/subtraction, round to least precise decimal place; for multiplication/division, round to least number of significant figures.

  • What is dimensional analysis?

    Dimensional analysis uses conversion factors to change units systematically.