Ch1

Chapter Outline

• Section 1.1 Classification of Matter

• Section 1.2 Properties of Matter

• Section 1.3 Matter and Energy

• Section 1.4 The Scientific Method, Hypotheses, Theories, and Laws

• Section 1.5 The International System of Units

• Section 1.6 Significant Digits

• Section 1.7 Dimensional Analysis

• Section 1.8 Density

• Section 1.9 Temperature Scales

Section 1.1 Classification of Matter

• Classification of Matter

  • Matter can be classified based on its composition.

Types of Matter

• Elements: Pure substances that consist entirely of one type of atom.

• Compounds: Pure substances made up of two or more elements that are chemically combined in a fixed ratio.

• Mixtures: Combinations of two or more substances that are not chemically bonded and can vary in composition.

  • Types of Mixtures:

  • Heterogeneous Mixtures: Composition is not uniform (e.g., salad).

  • Homogeneous Mixtures (Solutions): Composition is uniform throughout (e.g., saltwater).

Section 1.2 Properties of Matter

• Properties of Matter

  • Different types of properties can help identify substances.

  • Types of properties:

  • Physical Properties: Characteristics that can be observed without changing the chemical composition.

    • Examples: color, melting point, conductivity.

  • Chemical Properties: Describe the chemical reactions a substance undergoes.

Changes in Matter

• Physical Changes: Changes that do not alter the chemical composition of a substance.

• Chemical Changes: Changes that result in the formation of new chemical substances.

Section 1.3 Matter and Energy

• Matter: Anything that has mass and occupies space.

• Mass: A measure of the amount of matter in an object, not dependent on location.

• Weight: The force exerted by gravity on an object’s mass; weight can change depending on location.

Energy

• Definition of Energy: The capacity to do work.

• Law of Conservation of Energy: Energy cannot be created or destroyed but can only be converted from one form to another.

• Forms of Energy:

  • Heat, chemical, nuclear, mechanical (kinetic and potential), electrical, sound, electromagnetic radiation.

Section 1.4 The Scientific Method, Hypotheses, Theories, and Laws

• Scientific Method: A structured approach to inquiry that involves observation, hypothesis formulation, experimentation, and revision of hypotheses based on results.

  • Steps in the Scientific Method:

  1. Observation

  2. Hypothesis formulation

  3. Experimentation

  4. Revision of hypotheses based on experimental results

Differences among Hypotheses, Theories, and Laws

• Hypothesis: A testable explanation for a set of observations.

• Theory: A well-substantiated explanation acquired through the scientific method and repeatedly tested.

• Law: A statement based on repeated experimental observations that describe some aspect of the world.

Section 1.5 The International System of Units (SI)

• SI Units: Recognize base units and their prefixes for converting measurements between units.

SI Base Units

• Table 1.3: SI Base Units

  • Length: Meter (m)

  • Mass: Kilogram (kg)

  • Time: Second (s)

  • Temperature: Kelvin (K)

  • Amount of substance: Mole (mol)

  • Electric current: Ampere (A)

  • Luminous intensity: Candela (cd)

SI Prefixes

• Table 1.4: Common SI Prefixes

  • Tera- (T): $10^{12}$

  • Giga- (G): $10^{9}$

  • Mega- (M): $10^{6}$

  • Kilo- (k): $10^{3}$

  • Deci- (d): $10^{-1}$

  • Centi- (c): $10^{-2}$

  • Milli- (m): $10^{-3}$

  • Micro- (μ): $10^{-6}$

  • Nano- (n): $10^{-9}$

  • Pico- (p): $10^{-12}$

  • Femto- (f): $10^{-15}$

  • Atto- (a): $10^{-18}$

SI Derived Units

• Table 1.5: SI Derived Units

  • Volume: Cubic meter (m³)

  • Speed: Meter per second (m/s)

  • Acceleration: Meter per second squared (m/s²)

  • Density: Kilogram per cubic meter (kg/m³)

  • Frequency: Hertz (Hz) or $s^{-1}$

  • Force: Newton (N) defined as kg·m/s²

Section 1.6 Significant Digits

• Significant Digits: Indicate the precision of a measurement or calculated result.

Types of Measurements

• Qualitative Measurements: Describe characteristics, such as color or smell.

• Quantitative Measurements: Provide numerical values related to the amount of a substance.

Rules for Significant Digits

(1 of 2)

• All non-zero digits in a measurement are significant.

• Leading zeros (before non-zero digits) are not significant.

• Zeros between significant digits are significant.

(2 of 2)

• Trailing zeros in a decimal number are significant.

• Trailing zeros in an integer without a decimal point are ambiguous.

• All digits in scientific notation coefficients are significant.

Calculating with Significant Digits

• Addition and Subtraction: Round to the least number of decimal places present in the original measurements.

• Multiplication and Division: Answer limited by the measurement with the fewest significant digits.

• Exact Numbers: Do not limit significant figures; these include defined quantities and counted numbers.

Section 1.7 Dimensional Analysis

• Dimensional Analysis: A method that uses units of measurement to help set up calculations. This technique ensures that equations remain consistent and helps in converting units appropriately.

Section 1.8 Density

• Density: Defined as mass per unit volume.

  • Density formula: $ext{Density} = rac{ ext{Mass}}{ ext{Volume}}$

  • Units: g/mL, g/cm³.

  • Can be used as a conversion factor for mass and volume.

Densities of Common Substances at 25℃ (Table 1.7)

• Aluminum: 2.70 g/mL

• Copper: 8.96 g/mL

• Gold: 19.3 g/mL

• Iron: 7.87 g/mL

• Lead: 11.3 g/mL

• Mercury: 13.53 g/mL

• Platinum: 21.5 g/mL

• Water (at 25°C): 0.997 g/mL, (at 4°C): 1.000 g/mL

Section 1.9 Temperature Scales

• Temperature Scales: Distinguish among Fahrenheit, Celsius, and Kelvin.

  • Conversion between scales is necessary in scientific contexts.

Comparison of Temperature Scales (Figure 1.21)

• Common Points:

  • Normal boiling point of water: 212 °F = 100 °C = 373.15 K

  • Freezing point of water: 32 °F = 0 °C = 273.15 K