midterm Flashcards
what is the emergency equpiment in the lab?
-exit door
-eye wash station
-fire exinguisher
-saftey shower
-fire blanket
-first aid kit
matter
-anything that has mass and volume
volume
-amount of three dimensional space an object takes up
mass
-measure of amount of matter
atom
-small unit of an element that maintains its chemical identity
element
-pur substance
-cannot be broken down into simpler, stable substances
-is made of 1 type of atom
kinetic molecular theory of matter
-all matter is composed of particles that are always moving
-particles have space between them
-more energy = more space
-all particles have energy
-temperature is the measure of the average kinetic energy of particles
-if you change the temperature a change in state may occur
-attractive forces between particles are stronger as particles are closer together
characteristics of a solid
-definite shape and volume
-particles packed close together
-particles vibrate in a fixed motion
-strong attractive forces
-low energy
characteristics of a liquid
-definite volume but not shape
-particles are somewhat close together but can slide past each other
-particles flow past each other
-strong attractive forces
-medium energy
characteristics of a gas
-no definite shape or volume
-particles are spaced out
-particles move with great speed
-weak attractive forces
-high energy
pure substance
-fixed composition
-composed of only one type of particle
what are the 2 types of pure substances?
-compounds
-elements
what are the 2 types of pure substances made of?
-elements are made of atoms
-compounds are made of molecules or ions
mixture
-physical combination of two or more substances
-identities and properties of the substances are indivdually retained
-can be separated by physical means
mixture vs. compound
-compounds have a definite composition
-mixtures don’t, their composition varies
heterogeneous mixture
-not the same throughout
-particles are large enough to see
-not uniform
-ex. oil and water
homogeneous mixture
-appears the same throughout
-particles don’t settle out when left standing
-aka a solution
-ex. saltwater
what are the different separation techniques?
-filtration
-evaporation
-distillation
-decanting
-chromatography
filtration
-passing a mixture through a filter
-uses property of size
evaporation
-letting a mixture evaporate
-uses the property of vaporization point
-ex. saltwater
distillation
-separates liquid mixtures
-liquid with lowest boiling point vaporizes first
-collect vapor and condense as pure liquid
-uses property of vaporization point
evaporation vs. distillation
-evaporation is concerned with collecting the solid
-distillation wants the pure liquid that is vaporized
decanting
-separation by pouring off the liquid layer and leaving solids behind
-uses property of state of matter
chromatography
-separates based on attraction
-ex. hydrophobic
what are the diatomic elements?
-hydrogen
-nitrogen
-oxygen
-flourine
-chlorine
-bromine
-iodine
solid to liquid
melting
liquid to gas
evaporation
gas to solid
depostion
liquid to solid
freezing
solid to gas
sublimation
gas to liquid
condensation
extensive vs. intensive physical properties
-extensive depends on amount of matter present
-ex. mass and volume
-intensive does not depend on matter present
ex. color, density, boiling point, malleability, ductility
chemical properties
-change that results in a different substance
-ex. burning, rotting, tarnish, rusting, digesting
physical properties
-can be observed/measured without changing the identity of the substance
-ex. cutting, grinding, freezing, melting, evaporating
desnity
-ratio of mass to volume in a substance
-intensive
d= m/v
accuracy
-closeness of measurements to correct value
precision
-closeness to measurements to each other
science
-the process of studying the natural world
-search for knowledge
steps of scientific method
-state the problem
-form a hypothesis
-test hypothesis
-record data
-draw conclusions
branches of science
-life
-physical
-earth and space