help needed for 2 assgn due in 24 hours
MATTER
Definition
- anything that occupies space and possesses mass
Properties of Matter
- the signs/characteristics that serve to identify substances
A. Physical Properties
- those characteristics of a substance as it exists in nature
- properties that can change without involving a change in chemical composition
A. Physical Properties
1. See, touch, feel or descriptions
- color, odor, taste, boiling point, freezing point
2. State of matter
- solid, liquid, or gas
A. Physical Properties
3. Density
- the mass per unit volume
- or the mass of an object divided by its volume
mass
volume
= Density
- things that are heavy tend to be more dense
A. Physical Properties
4. Viscosity
- resistance to flow
- blood is more viscous than water
- affects the boiling and freezing points
B. Chemical Properties
- the characteristics that are observed only when the substance is interacting with other substances
- thereby changing the composition of the substance
- it’s “reactivity”
*****
STATES
OF MATTER
Solids
- have a definite shape and volume
- do not flow
- particles are packed tightly together in an organized fashion.
Properties of Solids
- Melting
- changing states from solid to liquid
- Sublimation
- changing states from solid to gas
- skips the liquid state
Liquids
- have no definite shape but do have a definite volume
- particles are farther apart than in solids
- a substance that flows readily
Properties of Liquids
- Viscosity
- resistance to flow
- the resistance that a liquid exhibits to the flow of one layer over another arising from the molecular attraction between the molecules of a liquid
- Surface Tension
- the attraction of the molecules for each other at the surface of a liquid
- Diffusion
- the movement of molecules from an area of higher concentration to an area of lower concentration
- Freezing
- a change of state of matter from a liquid to a solid by the loss of heat
- Solidification
- the ability of a liquid or a gas to become firm and compact into a solid
- Boiling
- the rapid passage of liquid particles to the vapor state by forming bubbles through the action of heat
- Crystallization
- the process by which a substance is given definite form
- Vaporization
- the physical change from a liquid to a gas
- Volatility
- having the quality of being easily converted at a relatively low temperature from the liquid to the gaseous state
Gases
- have no definite shape or volume
- will always fill their container
Properties of Gases
- Condensation
- a change in state of matter from a gas to a liquid
- Diffusion
- as seen above in liquids
- Vaporization
- gas particles spreading further out
SOLID
LIQUID
GAS
Melting
Condensation
Vaporization
Freezing
Sublimation
The state of matter is dependent upon:
Temperature
and
Pressure
Changes in Matter
Physical Changes
- changes in the condition or state of a substance
- only changing the physical characteristics
- do not form new substances or change the composition
Chemical Changes
- changes that result in the formation of new substances
- occur only when a chemical reaction takes place
- change the composition of the original substance
- lead to new chemical and physical properties
PHYSICAL CHANGES
boiling water
freezing water
breaking glass
melting dry ice
CHEMICAL CHANGES
preservation of a remains
decomposition
cremation
rusting of a nail
burning wood
COMPOSITIONAL
FORMS
OF
MATTER
- all matter can be divided into three compositional classes
Elements
Compounds
Mixtures
A. Elements
- the basic units of all matter
- the building blocks
- you would no longer have an element
- elements cannot be broken down (or decomposed) chemically
To avoid writing out the entire name every time an element was used a “chemical shorthand” was developed
-
-
-there is one assigned to each element
each element is given a symbol known as the “Atomic Symbol”
also known as an abbreviated expression for an element
- usually an abbreviation of their names
-generally symbols are taken from the first letter of the name
-others must have two letters to distinguish them
-
Carbon and Chlorine
C and Cl
-- 1st letter always capitalized
-- 2nd letter always in lower case
-some are taken from their Latin names
-
-
Fe for Iron
Latin—Ferrum
K for Potassium
Latin—Kalium
!!!!!!!
LIST OF
REQUIRED ELEMENTS
!!!!!!!
Aluminum Al
Bromine Br
Calcium Ca
Carbon C
Chlorine Cl
Copper Cu
Hydrogen H
Iodine I
Iron Fe
Magnesium Mg
Mercury Hg
Nitrogen N
Oxygen O
Phosphorus P
Platinum Pt
Sodium Na
Sulfur S
Elements are divided into 2 general groups
1)
2)
Metals
Non-metals
1) Metals
Physical Properties
-
-
-
-
-
- Exception:
conduct heat and electricity
have a luster
some are ductile
some are malleable
most are solids
Mercury is a liquid
- metal elements exhibit a positive electrical charge
2) Non-metals
Physical Properties
-
-
-
-
-
not good conductors
usually brittle
not malleable
not ductile
some are solids, some liquids, some gases
- nonmetal elements exhibit a negative electrical
1 2 3 4 5 6 7 8
35
B. Compounds
-
-
-
substances composed of two or more elements combined chemically in definite proportions by mass
cannot be separated by physical means - only chemically
have both chemical and physical properties different from the constituent elements
***
Examples of Compounds:
-
-
-
-
salt
carbon dioxide
water
formaldehyde
NaCl
CO2
H2O
HCHO
C. Mixtures
-
-
-
a combination of two or more substances not chemically united and NOT in definite proportion by mass
may be separated by physical means
elements or compounds may be present in any proportion
- embalming fluid is a mixture
- blood
- milk
- air
- saltwater
- HCHO gas dissolved in water and “mixed” with all the other constituents
Other examples of Mixtures