Scientific Method
Organized series of steps intended to help solve a problem or answer a question
Scientific Method Steps
Identify the problem/question; form a hypothesis; test the hypothesis; make observations and collect data; form a conclusion
Theory
Set of tested hypotheses that gives an explanation of some natural phenomenon
Law
Statement that summarizes what happens
Law of Conservation of Mass
States that the total mass of materials is not affected by a chemical change in those materials
Measurement
Quantitative observation with a number and a unit
Mega (m)
10?
Kilo (k)
10?
Hecto (h)
10?
Deka (da)
10?
Deci (d)
10??
Centi (c)
10??
Milli (m)
10??
Micro (�)
10??
Nano (n)
10??
Mass
Measure of the amount of matter an object is composed of
Weight
Measure of the force gravity exerts on an object
Accuracy
Agreement of a particular value with the true value; close to the "true" value of a measurement
Precision
Refers to the degree of agreement among several measurements of the same quantity; reflects reproductibility of a given measurement
Random Error
Measurement has an equal probability of being high or low; occurs in estimating last digit
Systematic Error
Occurs in the same direction each time, either high or low
Dimensional Analysis
Using proportions, ratios, and fractions to aid in converting one unit of measure into another
Temperature
Measure of the average kinetic energy of the particles of a substance
Density
Mass of substance per unit volume of the substance
Matter
Anything occupying space and taking up mass; material of the universe
Solid
Definite volume and shape
Liquid
Definite volume but no specific shape
Gas
No fixed volume or shape
Mixture
A material of variable composition that contains two or more substances
Plasma
Composed of charged particles, no definite volume or shape
Homogeneous
Having visibly indistinguishable parts
Heterogeneous
Having visibly distinguishable parts
Solution
Homogeneous mixture
Pure Substance
One with constant composition
Physical Change
A change in the form of a substance, but not in its chemical composition; chemical bonds are not broken in a physical change
Chemical Change
The change of substances into other substances through a reorganization of the atoms; a chemical reaction
Compound
Substance with constant composition that can be broken down into elements by chemical processes; ex. electrolysis of water into oxygen and hydrogen
Distillation
Process used to separate the components of a mixture; depends on volatility of components (most volatile component vaporizes at lowest temperature and passes through a cooled tube, where it condenses back into a liquid)
Filtration
Process used to separate the components of a mixture; mixture is poured onto a mesh
Chromatography
Two phases, mobile and stationary; separate b/c parts of the mixture have different affinities for each phase and separate at different rates; paper used for stationary phase, liquid used for mobile phase; drop of mixture is placed on paper, then dipped i