MIDTERM STUDY (Unit 1) Flashcards
The steps of the scientific method (5):
- make observation & stating a problem
form hypothesis - test hypothesis
record /analyze data
-draw conclusion
Qualitative Observations:
using the senses to observe qualities - non-numerical properties
Quantitative Observations:
measurements or quantities- numerical
Independent Variable:
the variable that is changed during the experiment
Dependent Variable:
the variable that is observed during the experiment (result of changing the independent variable)
Science:
the search for scientific knowledge
Technology:
the application of science (making it useful)
Scientific Theory:
an explanation abt the natural world (not a guess), based on hypothesis and observations supported by testing
-explains how and why
Scientific Law:
a statement abt the natural world
- does not explain how or why
Hypothesis:
proposed explanation that is not tested
Theory:
well-tested explanation
All matter is composed of what:
particles that are in constant motion
More energy in particles =
more space between them
States of matter in order from less energy to more energy
Solid, Liquid, Gas
All particles of matter have..
energy
Temperature:
measure of the average kinetic energy of the particles
Increase Temp. =
Increase Energy
States of matter in order from strong attractive force to weak
Solid, Liquid, Gas
Chemistry:
study of the composition of matter and the changes it undergoes
Units of matter:
Atom and Element
Atom:
smallest unit of an element that maintains chemical identity of that element
Element:
pure substance that cannot be broken down + made up of only one type of atom
Matter:
Anything that has mass and volume
Mass:
measure of the amnt of matter
Volume:
amnt of three dimensional space an object occupies
Characteristics of Solid:
-Definite shape/volume
-packed close together
-vibrate in a fixed position
-very strong force of attraction / low energy
Characteristics of Liquid:
-definite volume, no definite shape
- close together but slide past one another
– move past another, slide, flow
- Strong force of attraction, medium energy
Characteristics of Gas:
-no definite volume, no definite shape
- spread out as far as possible
-move with great speed
-weak force of attraction, very high energy
Pure substance has-
a fixed composition (composed of just one type of particle)
+ are either compounds or elements
Elements:
-simplest pure substance
-cant be broken down by ordinary means
-made up of only one atom
Compounds
-pure substance-definite composition
-2 or more elements combined through chemical reaction
-Composed of definite group of molecules/ ions that are chemically bonded
Chemical and physical properties of a compound differ from:
those of the elements that make up the compound
Mixture:
-physical combo of 2 or more substances
-identities/properties of individual substances are retained
-can be separated by physical means
Two types of mixtures:
Homogeneous and heterogeneous
Heterogeneous mixture:
-mixture does not appear the same throughout
-particles large enough
-not uniform
Homogenous mixture:
-mixture that appeares same throughout
ex.air
Filtration:
uses physical property of SIZE to filter mixture
Distillation:
uses physical property of BOILING POINT to separate liquid mixture.
Evaporation:
uses physical prop of VAPORIZATION POINT (evaporation/boiling)
Decanting:
-uses physical property of STATE OF MATTER
-liquids are fluid and SOLUBILITY to separate mixture
Diatomic elements:
are only found in pairs when in pure state
(the 7 in chart)
Physical properties:
properties that can be observed/measured without changing substance into another substance
ex. density, boilig/melting point, texture, shape, color
Extensive properties (M.V.L):
Depend of amnt of matter present
EX. mass,volume,length
Intensive properties:
do not depend on the anmt of matter present
EX. density, color, hardness
Chemical properties:
properties that relate to a substance’s ability to change - produce new substance
ex.rusting, tarnishing, supports combustion, reacts with acids, water, or ocygen
Physical change:
original substance is not chemically changed
+original substance is physically altered, but still present
ex. evaporation, melting, dissolving salt in water, cutting
Chemical Change (reactions):
Og substances= reactants
New substance formed= products
Density:
Ratio of mass to volume of a substance
g/cm 3 :
used for solids
g/mL:
liquids and gases
Separation techniques (F.E.D.D.) :
-Filtration
-Evaporation
-Distillation
-Decanting
two types of physical properties:
Intensive and extensive
Difference between compounds and mixtures?
Compound: have a definite composition
Mixtures: have no definite composition
What is a Homogeneous mixture also called:
a solution
Two types of variables:
Intensive and Extensive
