Notes

1.1
chemistry - the study of composition properties and interactions of matter

hypothesis - tentative explanation of observations that act as a guide for gathering and checking information

laws of science - summarize vast number of experimental observations and describe or predict some facet of natural world

theories - well substantiated, comprehensive, testable explanations of particular aspects of nature

scientific method - path of discovery that leads from question and observation to law or hypothesis to theory, combined with experimental verification of hypothesis and necessary modification of theory

macroscopic domain - familiar to us, realm of everyday large enough encompassed by sight or touch

microscopic domain - imaginative aspects of chemistry, molecules, cells, atoms

symbolic domain - specialized language that represents components of macroscopic and microscopic domains (chemical formulas, equations)

1.2
Matter - anything that occupies space and has mass

solid - rigid and possess a definite shape

liquid - flows and takes shape of its container

gas - takes both shape and volume of its container

plasma - gaseous state of matter that contains appreciable numbers of electrically charged particles

mass - measure of the amount of matter in an object

weight - force that gravity exerts on an object

pure substance - type of matter with constant composition

elements - pure substance that cannot be broken down into simpler substances by chemical changes

compounds - pure substance that can be broken down by chemical changes

mixture - two or more types of matter that can be present and can be separated by physical changes

heterogenous mixture - mixture with composition that varies from point to point

homogeneous mixture (solution) - uniform composition that appears visually the same throughout

atom - smallest particle of an element that has properties of that element and can enter into chemical combination

molecule - two or more atoms joined by strong forces called chemical bonds

1.3
physical property - characteristic of matter that isnt associated with a change in its chemical composition

physical change - change in the state or properties of matter without any accompanying change in the chemicals identities of the substance contained in the matter (wax melting, sugar in coffee, steam condenses into water)

chemical property - the change of one type of matter into another type (flammability, toxicity, acidity)

chemical change - produces one or more types of matter that differ from the matter present before the change

extensive property - property of matter that depends on amount of matter present (mass and volume)

intensive property - property of matter that doesnt depend on the amount of matter present (temperature)

1.4
units - standards of comparison for measurements

SI Units (international system of units)

density - ratio of the mass of a sample of the substance to its volume

1.5
exact number - number that does not change while the counting process is underway

significant figure - digits in a measurement, including the uncertain last digit

- zeroes at the beginning of decimal number arent significant (0.003 has 1 sig fig)

precision - when results are all similar

accuracy - when results are close to true/accepted value

1.6
unit conversion factor - ratio of 2 equivalent quantities expressed with different measurement units


sig fig in calculation

addition - round result to same number of decimal place as number with fewest decimal places in terms of adding (1.0023 + 4.383 = 5.385, not 5.3853)

multiplication - round result to same number of digits as number with fewest sig figs in terms of multiplication (0.4*1.4=0.6, not 0.56) (4 sig fig x 2 sig fig = 2 sig fig answer)