chem-chapter 1a, 1b

chemistry

study of properties of matter, interactions between matter, and changes of matter and the energy associated with those changes

matter

anything that has mass and occupies space (i.e., has volume)

composition

specifies the types and amounts of simpler substances that make up a sample of matter—-often expressed in mass percents

substance

has definite, fixed composition and distinct properties (i.e., either an element or a compound)

mixture

is composed of a physical intermingling of two or more substances and whose composition is variable (i.e., might contain more, or less, of its various constituent

substances)

aqueous solutions

physical property

can be measured/observed without changing the composition or identity of a substance

chemical property

can be observed only during a chemical change

macroscopic properties

can be measured directly

submicroscopic properties

are deduced indirectly from macroscopic measurements We create models that relate macroscopic measurements/properties to microscopic properties. Consistently, understanding of the submicroscopic level properties helps us to account for and explain macroscopic behavior

solid

fixed shape, definite volume, composition: substance

liquid

indefinite (of a container) shape, definite volume, composition: mixture

gas

indefinite (of a container) shape, indefinite (of a container) volume, composition: homogeneous/heterogeneous

physical change

a change in (physical) properties without any change in the composition or identity of a substance

chemical change

a change in the composition or identity of a substance (which is, naturally, accompanied by changes in physical and chemical properties)

kinetic energy

related to motion. E_k=0.5mu². m=mass of a body, u=speed of a body

potential energy

related to the position in a force field (electrostatic). E_p=(Q₁Q₂)/d. d=distance btwn charges Q₁ and Q_2. Charges may be positive (Q>0) or negative (Q<0); there is an attraction between charges when E_p is negative.

energy

most processes lead to the lowering of energy. energy can be converted from one form to another but NOT created nor destroyed

fundamental units

mass, kilogram, kg

length, meters, m

time, seconds, s

temperature, Kelvin, K

amount of substance, moles, mol

electric current, ampere, A

luminous intensity, candela, cd

temperature

a measure of the amount of thermal energy that an object contains

heat

thermal energy transferred from a hotter system to a cooler system that are in contact

mass

amount of matter an object contains

weight

measure of force that is equal to the gravitational pull on an object

kelvin formula

T (inK)= T (in C) + 273.15

celsius formula

T (inC)= (5/9) (T (in F ) -32)