Chapter 1 Vocabulary Flashcards
Pure Substance
same chemical and physical properties throughout; cannot be separated into simpler substances by a physical process
Can be an element or a compound
What is a physical process?
a transformation of a sample of matter that does not alter the chemical identity
Element
a pure substance that cannot be separated into simpler substances by any chemical process
Compound
a pure substance composed of two or more elements bonded together in fixed proportions; can be broken down into individual elements by chemical reactions
Mixture
combination of two or more substances; can be homogenous or heterogeneous
homogenous mixture
components are distributed uniformly throughout the sample and have no visible boundaries or regions
heterogenous mixture
the components are not distributed uniformly and may have distinct regions of different composition
Atom
smallest particle of an element that retains the chemical characteristics of that element
Molecule
assembly of two or more atoms that are held together in a characteristic pattern by chemical bonds
Chemical formula
notation for representing elements and compounds; consists of symbols of elements and subscripts identifying the number of atoms of each element in one molecule
Chemical reaction
the transformation of one or more substances into different substances
Chemical equations
Use chemical formulas to express
the identities of substances involved
in a reaction; Use coefficients to indicate
quantities of substances involved in
a reaction.
Law of Constant Composition
All samples of a particular compound contain the same elements combined in the same proportions.
Example:
* Water (H2O)
* Consists of two units of hydrogen (H) combined with one unit of oxygen (O)
* Elements and proportions are represented by chemical formulas.
Ions
compounds consisting of positively or negatively charged particles
Can be Cations: positively charged ions
Ex: Calcium ion is Ca^2+
Can be Anions: negatively charged ions
Ex: Hydroxide ion is OH^-
Ways to represent bonding and shape for an arrangement of atoms
structural formulas, ball-and-stick model, and space-filling model