Chemistry
the science that deals with the materials of the universe and the changes that these materials undergo
Why is chemistry the central science?
all other sciences use chemistry.
Chemistry Change
A substance is changed into a a different substance.
3 steps of chemistry?
Recognize the problem
Formulate the Hypothesis
Perform experiments to test the hypothesis
Recognize the problem?
state the problem and collect the data
2 types of measurements:
Qualitative and Quantitative
Qualitative?
No number or unit.
Hot/Cold
Formulate a Hypothesis?
Possible explanation for the observation
(this can be observed and measured)
Hypothesis?
(Formulate a Hypothesis)
a patient insulin level is low
(insulin transport glucose across cell membranes)
Laws?
Predict what will happen
Theories?
Explain why something happens
Model/Theory
1.A set of tested hypothesis that gives an overall explanation of some parts of nature.
2.If the same observation applies to different systems, than the statement is a natural law.
Why is chemistry important?
1. gather and organize info
2. learn to find patterns in information
3. Analyze patterns in information
4. develop skills to predict further events based on patterns of behavior
5. develop problem solving skills
Mass?
kilogram (kg)
Length?
Meter (m)
Negative Exponent?
a negative power results when the decimal point is moved to the right.
What is matter?
anything that contains mass and occupies space
(can be measured and balanced)
Matter example:
Ice
Steel
(sunlight and heat is not matter, B/C IT CANNOT BE WEIGHED ON A BALANCE PAN)
Matter exists in 3 states
Solid, liquid, gas
Solid
Has a fixed volume and shape, and is RIGID
Liquid
Has a definite volume but takes the shape of its container
(20 oz of pop...indifferent bottles)
Gas
has no fixed volume or shape; takes the shape and volume of its container
(like balloons)
Physical Properties
The observation of these properties dont change its chemical conditions
-Odor
-Color
-Volume
-State
-Boiling Point
-Melting Point
-Pulvering
-Melting
(same before and after observation)
Water H20
Ice H2O
Freezing
liquid to solid
Melting
solid to liquid
Boiling
liquid to gas
condensation
Gas to liquid
vapoization
solid to gas with no melting - skips a step
Chemical Properties
The substances ability to undergo a chemical reaction
(Burning, Decomposition, tarnishing, fermentation, photosynthesis, metabolism, reacting and not reacting and CHANGING COLOR)
Description of non changing color is a physical property...
P.P. dont affect the chemical composition of the substance
Change of color is a chemical property T/F?
True
Hydrolysis is a chemical--->
2H20--->2H2+ O2
Cooking and baking are...
chemical changes
Hydrogen Peroxide brightens teeth
(1) Chemical
Nail polish removal evaporates when bottles open
physical (Liquid to gas)
Perfume smells
physical
chopping wood
physical
burning wood
chemical
Mothballs Vaporize
physical (solid to gas)
Burning Brandy
chemical
Antacid tablet, fizzles, releasing carbon dioxide which comes in contact with stomach acid
chemical
Whole milk curdles if vinegar come in contact with it
chemical (curdles : spoiled chemical reaction)
Banana ripens
chemical reaction
driving car
chemical
Pure substances
elements and compounds
-Always have the same composition
2 types of pure substances
elements and compounds
Elements
fundamental substances than CANNOT be broken down into other substances by chemical means.
-elements are represented by symbols
113 ELEMENTS in periodic table
Compounds
substances that CAN be broken down into elements through chemical reactions
-formulas with 2 or more elements
-Name of compound containd 2 or more words
Ex; H2O - HYDROGEN and OXYGEN
MIXTURE?
substances that can have variable compositions
-HAVE 2 OR MORE SUBSTANCES
(EX; wood, wine, coffee, tap water, well water)
2 types of mixture?
homogeneous and heterogeneous
Homogeneous ?
the mixture is the same throughout. A mixture with one face
-mixture with the same properties (salt water, air, brass)
Brass-melt copper and zinc together-physical changes
Heterogeneous
Regions have different properties
-2 separate layers that don't completely mix together
(sand, water, pizza)
Copper metal
pure substances and an element
orange juice
heterogeneous mixture if theres pulp/Homo without
Gasoline
Homogeneous Mixture
Chocolate Chip Cookies
Heterogeneous Mixture (chips and Dough)
seperation of mixtures
PHYSICAL METHODS
CHEMICAL METHODS
Seperation of Mixtures: Physical Methods
used to separate mixtures into pure substances
Separation of Mixtures: Chemical Methods
used to break up chemical substances
2 types of Physical methods
Filtration and Distillation
Filtration
separates solids and liquids
Ex: A sand and water Heterogeneous can be separated
Distillation
separates liquid mixtures
Ex: sea water contains minerals