CHEM 101: CHAPTER 1
69 Cards in this Set
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o Matter:
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the physical material of the universe; anything that has mass and occupies space
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o Property:
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any characteristic that allows us to recognize a particular type of matter and to distinguish it from other types
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o Elements:
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100 substances that cannot be further broken down
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o Atoms:
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infinitesimally small building blocks of matter
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Each element contains a unique type of
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atom
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Molecule:
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two or more atoms joined together in specific shape
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Even minor differences in composition or structure of molecules can cause
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profound differences in properties
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ยท Why Study Chemistry???
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o Chemistry is the central science, fundamental to understanding other sciences and technologies
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States of Matter
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Defined as a gas, liquid, or solid
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Gas:
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has no fixed volume or shape; rather, it conforms to the volume and shape of its container. Molecules far apart and moving at high speeds
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Liquid:
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has a distinct volume independent of its container but conforms to shape of container. Molecules packed close together but still move rapidly
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Solid:
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has both definite shape and a definite volume. Molecules held tightly together, only wiggle slightly in their fixed positionstion
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Changes in temperature and pressure can
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change the state of matter
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Pure Substances
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Defined as matter that has distinct properties and a composition that does not vary from sample to sample
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Examples of pure substances:
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Water, table salt
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All substances are either _____ or _____.
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elements or compounds
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Elements:
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substances that cannot be decomposed into simpler substances
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Compounds:
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substances composed of two or more elements; contain two or more kinds of atoms
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Mixture:
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combinations of two or more substances in which each substance retains its chemical identity
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How many elements are known?
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118
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C
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Carbon
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F
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Fluorine
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H
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Hydrogen
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I
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Iodine
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N
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Nitrogen
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O
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Oxygen
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P
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Phosphorus
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S
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Sulfur
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Al
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Aluminum
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Br
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Bromine
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Ca
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Calcium
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Cl
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Chlorine
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He
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Helium
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Li
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Lithium
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Mg
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Magnesium
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Si
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Silicone
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Cu
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Copper
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Fe
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Iron
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Pb
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Lead
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Hg
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Mercury
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K
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Potasium
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Ag
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Silver
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Na
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Sodium
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Sn
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Tin
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Elements interact with each other to
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form compounds
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Law of constant composition (law of definite proportions):
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the observation that the elemental composition of a compound is always the same
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Law of constant composition (law of definite proportions) was first started by:
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First stated by French chemist Joseph Louis Proust in 1800
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A pure compound has the same...
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...composition and properties regardless of its source
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Each substance in a mixture retains its
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chemical identity and properties, composition can vary
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Components- make up
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mixtures
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Heterogeneous mixture:
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do not have the same composition, properties, and appearance throughout
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Homogeneous mixture:
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mixtures that are uniform throughout
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Homogeneous mixture, also known as:
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Also known as solutions, can be solid liquid or gas
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Physical properties:
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can be observed without changing the identity and composition of the substance
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Examples of physical properties:
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o Color, odor, density, melting point, boiling point, and hardness
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Chemical properties:
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describe the way a substance may change or react to form other substances
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Examples of Chemical Property:
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Flammability is a common property
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Intensive properties:
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do not depend on the amount of sample being examined and are particularly useful in chemistry identification
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Extensive properties:
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depend on the amount of sample
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Examples of extensive properties:
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Mass and volume
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Physical change:
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a substance changes its physical appearance but not its composition
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Examples of physical change:
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Evaporation of water
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All changes of state are _____ ______.
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physical changes
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Chemical change:
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a substance is transformed into a chemically different substance
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Example of chemical change:
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When hydrogen burns in air
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Mixtures can be separated by
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taking advantage of their different properties
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Distillation:
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a process that depends on the different abilities of substances to form gases
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Chromatography:
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differing abilities of substances to adhere to the surfaces of solids
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Quantitative:
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associated with numbers, when a number represents a measured quantity
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Study Guide: Lectures 1 and 2