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Science and Measurement Overview

Chapter 1 Lecture Slides

• Title: Interactive General Chemistry 2.0 Reactions First

• Publisher: © 2023 Macmillan Learning

Chapter Outline

1. Classification of Matter

2. Properties of Matter

3. Matter and Energy

4. The Scientific Method, Hypotheses, Theories, and Laws

5. The International System of Units

6. Significant Digits

7. Dimensional Analysis

8. Density

9. Temperature Scales

Section 1.1 Classification of Matter

• Classification: Matter can be classified based on composition.

Definition of Matter

• Matter is anything that has mass and occupies space.

• Composed of about 100 elements.

• Elements are the simplest forms of matter that cannot be chemically broken down.

Pure Substances

• Atom: The smallest representative unit of an element.

• Chemical Bonds: Atoms bond to form compounds.

• Compound: A chemical combination of elements with unique properties.

• Pure substances include elements and compounds.

Section 1.2 Properties of Matter

Properties of Matter

• Each substance possesses a definitive set of properties for identification.

• Physical Properties: Describe identity without changing chemical composition (e.g., color, state).

• Chemical Properties: Characterize how substances react chemically.

Extensive vs. Intensive Properties

• Extensive Properties: Depend on quantity (mass, volume).

• Intensive Properties: Do not depend on quantity (density, color).

Section 1.3 Matter and Energy

Difference among Matter, Mass, and Weight

• Weight varies with gravitational pull; mass does not.

Energy Definition

• Energy: Capacity to do work.

• Law of Conservation of Energy: Energy cannot be created or destroyed; it can only change forms.

Section 1.4 The Scientific Method

The Scientific Method Steps

1. Gather observation data.

2. Formulate a hypothesis.

3. Conduct experiments to test the hypothesis.

Hypotheses, Theories, and Laws

• Hypothesis: Tentative explanation for observations.

• Theory: Comprehensive explanation that integrates many hypotheses and facts.

• Law: Statement based on consistent, observation without explanation.

Section 1.5 The International System of Units (SI)

Base SI Units

• Fundamental units include length (meter), mass (kilogram), time (second), and temperature (Kelvin).

SI Prefixes

• SI prefixes like kilo- (10^3) and centi- (10^-2) express large and small units.

Section 1.6 Significant Digits

Importance of Significant Digits

• Significant digits convey the precision of measurement results.

Rules for Significant Digits

1. All nonzero numbers are significant.

2. Leading zeros are not significant.

3. Zeros between significant figures are significant.

4. Trailing zeros in a decimal number are significant.

Section 1.7 Dimensional Analysis

Dimensional Analysis Method

• Treats units as algebraic quantities to aid in calculations.

Steps in Dimensional Analysis

1. Write the given quantity.

2. Multiply by conversion factors to achieve desired unit.

Section 1.8 Density

Density Definition

• Density quantifies mass per unit volume (g/mL or kg/L).

• It serves as a conversion factor in calculations between mass and volume.

Identifying Substances by Density

• Density is an intensive property, allowing for identification irrespective of sample size.

Section 1.9 Temperature Scales

Comparison of Temperature Scales

• Fahrenheit: Freezes at 32°F, boils at 212°F.

• Celsius: Freezes at 0°C, boils at 100°C.

• Kelvin: SI scale; freezes at 273.15 K, boils at 373.15 K.

Converting Temperature Values

• Formulas exist to convert between Fahrenheit, Celsius, and Kelvin.