Test 1 Study Guide: Chemistry in Our Lives, Measurements, Matter, and Atoms

Test 1 Study Guide: Chemistry in Our Lives, Measurements, Matter, and Atoms

Overview

This study guide covers foundational topics in General, Organic, and Biological (GOB) Chemistry, focusing on the scientific method, measurement, matter, and atomic structure. It is designed to help students prepare for a college-level chemistry exam.

Chapter 1: Scientific Method

1.1 Scientific Method

• Key Terms: Observation, Hypothesis, Experiment, Theory

• Observation: Gathering information using the senses or instruments.

• Hypothesis: A testable explanation for an observation.

• Experiment: A controlled procedure to test a hypothesis.

• Theory: A well-substantiated explanation based on repeated experiments.

Chapter 2: Chemistry and Measurements

2.1 Commonly Used Units

• SI Units: Standard units for length (meter), volume (liter), mass (gram), temperature (Celsius/Kelvin), and time (second).

• Metric System: Based on powers of 10. Know metric prefixes (kilo-, centi-, milli-, etc.).

• Unit Conversions: Use conversion factors to switch between units.

2.2 Significant Figures

• Definition: Digits in a measurement that are known with certainty plus one estimated digit.

• Rules:

  • Nonzero digits are always significant.

  • Zeros between nonzero digits are significant.

  • Leading zeros are not significant.

  • Trailing zeros are significant only if there is a decimal point.

• Calculations:

  • Multiplication/Division: Result should have the same number of significant figures as the measurement with the fewest significant figures.

  • Addition/Subtraction: Result should have the same number of decimal places as the measurement with the fewest decimal places.

2.3 Scientific Notation

• Expresses numbers as a product of a coefficient (between 1 and 10) and a power of 10.

• Example: $3.2 \times 10^4$

2.4 Conversion Factors (Dimensional Analysis)

• Use conversion factors to change from one unit to another.

• Arrange conversion factors so that unwanted units cancel out.

• Example: To convert 5.0 g to mg, use $1 \text{ g} = 1000 \text{ mg}$.

Chapter 3: Matter and Energy

3.1 States and Properties of Matter

• States: Solid, liquid, gas.

• Properties: Physical (color, density, melting point) and chemical (reactivity).

3.2 Temperature Conversions

• Know how to convert between Celsius, Fahrenheit, and Kelvin.

• Formulas:

• $T_{\text{K}} = T_{\text{C}} + 273$

• $T_{\text{C}}=(T_{\text{F}}-32)\times1.8$

• $T_{\text{F}}=T_{\text{C}}\times1.8+32$

3.3 Energy Conversions

• Joule (J) and Calorie (cal): $1 \text{ cal} = 4.184 \text{ J}$

• Energy Calculations: $q = m \times c \times \Delta T$

• Where $q$ = heat (J or cal), $m$ = mass, $c$ = specific heat, $\Delta T$ = temperature change.

3.4 Calorimetry

• Used to calculate energy absorbed or released by a substance.

• Food energy values are often given in kilocalories (kcal) or Calories (Cal).

• 1 Calorie (food Calorie) = 1 kcal = 1000 cal.

Chapter 4: Atoms

4.1 Properties of Metals, Nonmetals, and Metalloids

• Metals: Good conductors, malleable, ductile, shiny.

• Nonmetals: Poor conductors, brittle, dull.

• Metalloids: Properties intermediate between metals and nonmetals.

4.2 Atomic Structure

• Subatomic Particles: Proton (+), Neutron (0), Electron (-)

• Atomic Number (Z): Number of protons in the nucleus.

• Mass Number (A): Number of protons + neutrons.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Average Atomic Mass: Weighted average based on isotopic abundance.

4.3 Electron Configuration

• Electrons are arranged in energy levels (shells) around the nucleus.

• Use the periodic table to determine electron configuration.

• Exceptions: Cr and Cu have unique configurations.

4.4 Periodic Table Organization

• Elements are arranged by increasing atomic number.

• Groups (columns) have similar chemical properties.

• Periods (rows) indicate energy levels.

• Group 1: Alkali metals, Group 2: Alkaline earth metals, Group 17: Halogens, Group 18: Noble gases.

4.5 Trends in the Periodic Table

• Atomic Radius: Increases down a group, decreases across a period.

• Ionization Energy: Increases across a period, decreases down a group.

• Electronegativity: Increases across a period, decreases down a group.

Key Tables

Unit	Symbol	Conversion
Length	m	1 m = 100 cm = 1000 mm
Mass	g	1 kg = 1000 g
Volume	L	1 L = 1000 mL
Temperature	K, °C, °F	See formulas above

State	Shape	Volume	Compressibility
Solid	Definite	Definite	Low
Liquid	Indefinite	Definite	Low
Gas	Indefinite	Indefinite	High

Additional info: This guide is based on a study guide for a GOB Chemistry test and covers the first four chapters, aligning with standard introductory chemistry curricula.