Spencer L. Seager Michael R. Slabaugh Jennifer P. Harris Chapter 1: Matter, Measurements, and Calculations

MATTER & MASS Matter is anything that has mass and occupies space. Mass is a measurement of the amount of matter in an object. Mass is independent of the location of an object. An object on the earth has the same mass as the same object on the moon.

WEIGHT Weight is a measurement of the gravitational force acting on an object. Weight depends on the location of an object. An object weighing 1.0 lb on earth weighs about 0.17 lb on the moon.

PHYSICAL & CHEMICAL PROPERTIES PHYSICAL PROPERTIES OF MATTER Physical properties can be observed or measured without attempting to change the composition of the matter being observed. Examples: color, shape and mass CHEMICAL PROPERTIES OF MATTER Chemical properties can be observed or measured only by attempting to change the matter into new substances. Examples: flammability and the ability to react (e.g. when vinegar and baking soda are mixed)

PHYSICAL & CHEMICAL CHANGES PHYSICAL CHANGES OF MATTER Physical changes take place without a change in composition. Examples: freezing, melting, or evaporation of a substance (e.g. water) CHEMICAL CHANGES OF MATTER Chemical changes are always accompanied by a change in composition. Examples: burning of paper and the fizzing of a mixture of vinegar and baking soda

PARTICULATE MODEL OF MATTER All matter is made up of tiny particles called molecules and atoms. MOLECULES A molecule is the smallest particle of a pure substance that is capable of a stable independent existence. ATOMS Atoms are the particles that make up molecules.

MOLECULE CLASSIFICATION Diatomic molecules contain two atoms. Triatomic molecules contain three atoms. Polyatomic molecules contain more than three atoms.

MOLECULE CLASSIFICATION (continued) HOMOATOMIC MOLECULES The atoms contained in homoatomic molecules are of the same kind. HETEROATOMIC MOLECULES The atoms contained in heteroatomic molecules are of two or more kinds. homoatomicheteroatomic

MOLECULE CLASSIFICATION EXAMPLE Classify the molecules in these diagrams using the terms diatomic, triatomic, or polyatomic molecules. Solution: H 2 O 2 is a polyatomic molecule, H 2 O is a triatomic molecule, and O 2 is a diatomic molecule. Classify the molecules using the terms homoatomic or heteroatomic molecules. Solution: H 2 O 2 and H 2 O are heteroatomic molecules and O 2 is a homoatomic molecule.

CLASSIFICATION OF MATTER Matter can be classified into several categories based on chemical and physical properties. PURE SUBSTANCES Pure substances have a constant composition and a fixed set of other physical and chemical properties. Example: pure water (always contains the same proportions of hydrogen and oxygen and freezes at a specific temperature)

CLASSIFICATION OF MATTER (continued) MIXTURES Mixtures can vary in composition and properties. Example: mixture of table sugar and water (can have different proportions of sugar and water) A glass of water could contain one, two, three, etc. spoons of sugar. Properties such as sweetness would be different for the mixtures with different proportions.

HETEROGENEOUS MIXTURES The properties of a sample of a heterogeneous mixture depends on the location from which the sample was taken. A pizza pie is a heterogeneous mixture. A piece of crust has different properties than a piece of pepperoni taken from the same pie.

HOMOGENEOUS MIXTURES Homogeneous mixtures are also called solutions. The properties of a sample of a homogeneous mixture are the same regardless of where the sample was obtained from the mixture. Samples taken from any part of a mixture made up of one spoon of sugar mixed with a glass of water will have the same properties, such as the same taste.

ELEMENTS Elements are pure substances that are made up of homoatomic molecules or individual atoms of the same kind. Examples: oxygen gas made up of homoatomic molecules and copper metal made up of individual copper atoms

COMPOUNDS Compounds are pure substances that are made up of heteroatomic molecules or individual atoms (ions) of two or more different kinds. Examples: pure water made up of heteroatomic molecules and table salt made up of sodium atoms (ions) and chlorine atoms (ions)

MATTER CLASSIFICATION SUMMARY

MATTER CLASSIFICATION EXAMPLE Classify H 2, F 2, and HF using the classification scheme from the previous slide. Solution: H 2, F 2, and HF are all pure substances because they have a constant composition and a fixed set of physical and chemical properties. H 2 and F 2 are elements because they are pure substances composed of homoatomic molecules. HF is a compound because it is a pure substance composed of heteroatomic molecules.

MEASUREMENTS & UNITS Measurements consist of two parts, a number and a unit or label such as feet, pounds, or gallons. Measurement units are agreed upon by those making and using the measurements. Measurements are made using measuring devices (e.g. rulers, balances, graduated cylinders, etc.).

METRIC SYSTEM The metric system is a decimal system in which larger and smaller units are related by factors of 10. TYPES OF METRIC SYSTEM UNITS Basic or defined units [e.g. 1 meter (1 m)] are used to calculate derived units [e.g. 1 square meter (1 m 2 )].

THE USE OF PREFIXES Prefixes are used to relate basic and derived units. The common prefixes are given in the following table:

TEMPERATURE SCALES The three most commonly-used temperature scales are the Fahrenheit, Celsius and Kelvin scales. The Celsius and Kelvin scales are used in scientific work.

TEMPERATURE CONVERSIONS Readings on one temperature scale can be converted to the other scales by using mathematical equations. Converting Fahrenheit to Celsius. Converting Celsius to Fahrenheit. Converting Kelvin to Celsius. Converting Celsius to Kelvin.

TEMPERATURE CONVERSION PRACTICE Covert 22°C and 54°C to Fahrenheit and Kelvin.

COMMONLY USED METRIC UNITS

SCIENTIFIC NOTATION Scientific notation provides a convenient way to express very large or very small numbers. Numbers written in scientific notation consist of a product of two parts in the form M x 10 n, where M is a number between 1 and 10 (but not equal to 10) and n is a positive or negative whole number. The number M is written with the decimal in the standard position.

SCIENTIFIC NOTATION (continued) STANDARD DECIMAL POSITION The standard position for a decimal is to the right of the first nonzero digit in the number M. SIGNIFICANCE OF THE EXPONENT n A positive n value indicates the number of places to the right of the standard position that the original decimal position is located. A negative n value indicates the number of places to the left of the standard position that the original decimal position is located.

SCIENTIFIC NOTATION MULTIPLICATION Multiply the M values (a and b) of each number to give a product represented by M'. Add together the n values (y and z) of each number to give a sum represented by n'. Write the final product as M' x 10 n '. Move decimal in M' to the standard position and adjust n' as necessary.

SCIENTIFIC NOTATION DIVISION Divide the M values (a and b) of each number to give a quotient represented by M'. Subtract the denominator (bottom) n value (z) from the numerator (top) n value (y) to give a difference represented by n'. Write the final quotient as M' x 10 n '. Move decimal in M' to the standard position and adjust n' as necessary.