# 1: Matter and Measurements

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What is chemistry? Simply put, chemistry is the study of the interactions of matter with other matter and with energy. This seems straightforward enough. However, the definition of chemistry includes a wide range of topics that must be understood to gain a mastery of the topic or even take additional courses in chemistry. In this book, we will lay the foundations of chemistry in a topic-by-topic fashion to provide you with the background you need to successfully understand chemistry.

• 1.1: Chemistry - The Central Science
Chemistry is the study of matter and how it behaves. The scientific method is the general process by which we learn about the natural universe.
• 1.2: States of Matter
A state of matter is one of the distinct forms that different phases of matter take on. Three states of matter are readily observable in everyday life: solid, liquid, and gas. Each state has characteristic properties that are dictate by the nature of the matter and the conditions on which it exists.
• 1.3: Classification of Matter
Matter can be described with both physical properties and chemical properties. Matter can be identified as an element, a compound, or a mixture.
• 1.4: Chemical Elements and Symbols
An element is a substance that cannot be broken down into simpler chemical substances. There are about 90 naturally occurring elements known on Earth. Using technology, scientists have been able to create nearly 30 additional elements that do not occur in nature. Today, chemistry recognizes 118 elements—some of which were created an atom at a time.
• 1.5: Chemical Reactions- Examples of Chemical Change
Chemical reactions are the processes by which chemicals interact to form new chemicals with different compositions. Simply stated, a chemical reaction is the process where reactants are transformed into products. How chemicals react is dictated by the chemical properties of the element or compound- the ways in which a compound or element undergoes changes in composition.
• 1.6: Physical Quantities - Units and Scientific Notation
To understand chemistry, we need a clear understanding of the units chemists work with and the rules they follow for expressing numbers.
• 1.7: Measuring Mass, Length, and Volume
The SI base units specifies certain units for various types of quantities, based on seven fundamental units. We will use most of the fundamental units in chemistry. This section addresses the measurements: mass, length, and volume
• 1.8: Measurement and Significant Figures
Significant figures properly report the number of measured and estimated digits in a measurement. There are rules for applying significant figures in calculations.
• 1.9: Rounding Off Numbers
Before dealing with the specifics of the rules for determining the significant figures in a calculated result, we need to be able to round numbers correctly.
• 1.10: Problem Solving - Unit Conversions and Estimating Answers
A unit can be converted to another unit of the same type with a conversion factor. Using this method, called dimensional analysis or the factor label method, is an essential skill that will be applied in many chapters of this textbook.
• 1.11: Temperature, Heat, and Energy
Heat and temperature are a closely related topics, although the difference between the two are often conflated. The key difference is that heat deals with the transfer of thermal energy, whereas temperature is a metric of molecular kinetic energy. Heat is a process and temperature is a property.
• 1.12: Density and Specific Gravity
Knowledge of density is important in the characterization and separation of materials. Information about density allows us to make predictions about the behavior of matter.

1: Matter and Measurements is shared under a CC BY-NC-SA 3.0 license and was authored, remixed, and/or curated by LibreTexts.