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  • What is chemistry?

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

  • Define matter.

    Matter is anything that occupies space because of its volume and has mass.

  • What are the three main types of matter classification?

    Element: simplest matter with one kind of atom.
    Compound: two or more different elements chemically bonded.
    Mixture: physical combination of elements and/or compounds.

  • What is the scientific method?

    A procedure to ask questions, test ideas, and build scientific knowledge.

  • List the main steps of the scientific method.

    Make an observation, ask a question, formulate hypothesis & prediction, design & conduct experiment, collect & interpret data, draw conclusions, peer review & publish.

  • Difference between hypothesis, theory, and law.

    Hypothesis: testable explanation.
    Theory: well-supported explanation.
    Law: provably consistent phenomenon.

  • What are physical changes?

    Changes in physical state without changing composition, e.g., melting or dissolving.

  • What are chemical changes?

    Changes that alter chemical composition, forming new substances, e.g., rusting or burning.

  • Define reversible and irreversible changes.

    Reversible: can restore original structure (phase changes).
    Irreversible: permanent change (chemical reactions).

  • What is a chemical property?

    A property observed during a chemical reaction that changes the substance, e.g., reactivity with oxygen.

  • What is a physical property?

    A measurable property describing a substance's state without changing its chemical structure, e.g., density or color.

  • Difference between temperature and heat.

    Temperature: average kinetic energy of particles.
    Heat: transfer of thermal energy from hot to cold.

  • What is heat capacity?

    Amount of heat required to change a substance's temperature.

  • Define specific heat capacity.

    Heat required to raise 1 gram of a substance by 1 Kelvin.

  • What is scientific notation?

    A way to express very large or small numbers as a coefficient times 10 raised to an exponent.

  • What are SI base units?

    Standard units for physical quantities like mass (kg), length (m), time (s), temperature (K), amount of substance (mol), and electric current (A).

  • What are metric prefixes?

    Multipliers for base units, e.g., kilo (103), milli (10-3), micro (10-6).

  • What are significant figures?

    Digits in a number that contribute to its precision, including all certain digits plus one estimated digit.

  • Rules for significant figures in multiplication/division.

    Result should have the same number of significant figures as the factor with the least sig figs.

  • Rules for significant figures in addition/subtraction.

    Result should have the same number of decimal places as the number with the least decimal places.

  • What is dimensional analysis?

    A method to convert units by multiplying by conversion factors to cancel unwanted units.

  • Define density.

    Density is mass per unit volume, usually g/cm3 for solids/liquids and g/L for gases.

  • What is specific gravity?

    The ratio of a substance's density to the density of water at the same temperature; it is unitless.