Skip to main content
뒤로

Introduction to Chemistry: Matter, Measurement, and Calculations

컨트롤 버튼이 '내비게이션' 모드로 변경되었습니다.
1/23

이 집합의 용어 (23)

  • What is chemistry?

    Chemistry is the study of matter and the changes it undergoes, including what substances are made of, their properties, interactions, and chemical reactions.

  • Define matter.

    Matter is anything that has mass and occupies space.

  • List the four states of matter and one key characteristic of each.
    • Solid: definite shape and volume
    • Liquid: definite volume, no definite shape
    • Gas: no definite shape or volume
    • Plasma: high-energy charged particles
  • What are physical properties of matter?

    Properties that can be observed or measured without changing the substance's identity, such as color, density, melting point, and boiling point.

  • What are chemical properties?

    Properties that describe how a substance can change into another substance, like flammability and reactivity with oxygen.

  • Difference between physical and chemical change?

    Physical change: changes form but not identity (e.g., melting ice).
    Chemical change: produces new substances (e.g., burning wood).

  • How is matter classified?

    Matter is classified as pure substances (elements and compounds) or mixtures (homogeneous and heterogeneous).

  • What defines an element?

    An element is made of only one type of atom and cannot be broken down chemically into simpler substances.

  • What is a compound?

    A compound consists of two or more elements chemically bonded, with properties different from its elements (e.g., H\(_2O\)).

  • Difference between homogeneous and heterogeneous mixtures?

    Homogeneous: uniform composition (e.g., salt water).
    Heterogeneous: not uniform (e.g., salad).

  • What are the two parts of a measurement?

    A measurement includes a number and a unit (e.g., 25.0 g).

  • Name the SI units for length, mass, time, temperature, and amount of substance.
    • Length: meter (m)
    • Mass: kilogram (kg)
    • Time: second (s)
    • Temperature: kelvin (K)
    • Amount: mole (mol)
  • List common metric prefixes and their meanings.
    • kilo (k): 1,000
    • centi (c): 0.01
    • milli (m): 0.001
    • micro (μ): 0.000001
    • nano (n): 0.000000001
  • How do you convert Celsius to Kelvin?

    Use the formula \(K=\degree C+273.15\). For example, 25°C = 298.15 K.

  • What is density and its formula?

    Density measures mass per unit volume. Formula: \(D=\frac{m}{V}\).

  • What units are commonly used for density?

    Density is commonly expressed in g/mL or g/cm³. Note: 1 mL = 1 cm³.

  • Rules for identifying significant figures?
    • All nonzero digits are significant.
    • Zeros between nonzero digits are significant.
    • Leading zeros are not significant.
    • Trailing zeros in decimals are significant.
  • How to handle significant figures in multiplication/division?

    Result should have the same number of significant figures as the measurement with the fewest sig figs.

  • How to handle significant figures in addition/subtraction?

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

  • Difference between accuracy and precision?

    Accuracy: closeness to true value.
    Precision: closeness of repeated measurements to each other.

  • What is dimensional analysis?

    A method to convert units by multiplying by conversion factors equal to 1, ensuring unwanted units cancel out.

  • What are the main steps of the scientific method in chemistry?
    • Observation
    • Question
    • Hypothesis
    • Experiment
    • Data collection and analysis
    • Conclusion
  • Define hypothesis, theory, and law in chemistry.
    • Hypothesis: testable explanation or prediction.
    • Theory: well-supported explanation based on evidence.
    • Law: description of a consistent natural pattern.