matter & the atom...matter can be classified as either a pure substance or a mixture pure...
TRANSCRIPT
IN GENERAL…
Matter can be classified as either a PURE SUBSTANCE or a MIXTURE
Pure substances are further broken down into ELEMENTS and COMPOUNDS
The smallest unit of an element is an ATOM
SUBATOMIC PARTICLES
Particle Symbol Charge Mass LocationProton p+ +1 1 NucleusNeutron n0 0 1 NucleusElectron e- -1 0 Electron
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VOCAB
Nucleons: particles in the nucleus (protons & neutrons)
Atomic Number (Z): number of protons in the nucleus, identifies element
Mass Number (A): sum of protons and neutrons in the atom (whole number)
Average Atomic Mass: average of all of the mass numbers of all the isotopes of an element (decimal on periodic table)
MORE DEFINITIONS
Isotopes: atoms of the same element with different # of neutrons (and therefore different masses) Protium (1H), deuterium (2H), tritium (3H)
Nuclides: specific isotope of an element EX Carbon-14 or Carbon-12
Ions: an atom with a charge because it gained or lost electrons lost electrons + charge (Cation)Gain electrons - charge (anion)
ISOTOPE NOTATION
Atomic # _______
Mass # ________
# Protons _______
# Neutrons ______
# Electrons ______
3157
+N
HELPFUL HINTS
Neutral atoms: # protons = # electrons
# neutrons = mass # - atomic #
Ions: # electrons = atomic # - charge
PRACTICE – SOLVING FOR SUBATOMIC PARTICLESElement Atomic # Mass # Average
Atomic Mass
Protons Neutrons Electrons Isotope Notation
Ca
Bromine-81
Na+1
W
P-3
WARM UP – 2/1 COMPLETE THE CHART BELOWElement/ion Atomic
#Mass # Avg.
Atomic Mass
P+ n0 e- Isotope notation
Chlorine-36
6 8
20 18
Nickel-60
AVERAGE ATOMIC MASS
Weighted Average of all the mass numbers of all the isotopes of that element
EX: Calculate the average atomic mass of boron if a sample contains19.78 % Boron-10 (10.013 AMU)80.22% Boron-11 (11.009 AMU)
MORE EXAMPLES
What is the average atomic mass of an element with the following isotopes?
Magnesium-24 78.70%
Magnesium-25 10.13%
Magnesium-26 11.17%
MORE EXAMPLES
Calculate the average atomic mass of isotope X
If an isotope of Xenon has a mass of 133 AMU is it the most abundant isotope that exists for this element? Why or why not?
Mass Number Exact Weight Percent Abundance
14 14.003074 99.63
15 15.000108 0.37
WARM UP – 2/4
Determine the number of each subatomic particle in the following isotopes
50120𝑆𝑆𝑆𝑆 9
17𝐹𝐹 38𝐿𝐿𝐿𝐿
What is the average atomic mass of titanium?
VOCAB
Mass: the amount of matter (g or kg)
Matter: anything that has mass and takes up space (not energy!)
Atom: smallest unit of an element that is still that element
Element: Pure substance made of 1 kind of atom (on Periodic Table) EX: sodium, uranium, gold, oxygen
Compound: Pure Substance made of 2 or more elements chemically combined EX: salt, sugar, vinegar, water
PROPERTIES OF MATTER
Properties of matter are unique and can be used to distinguish between and identify different substances
Physical Properties: can be observed/measured without changing the substance Extensive Property: depends on the amount of matter present (external)Volume, mass, amount of energy Intensive Property: does NOT depend on the amount of matter (internal)Melting Point, Boiling Point, Density, Conductivity (electrical and heat)
EXTENSIVE VS INTENSIVE PRACTICE
Determine the extensive and intensive properties below
A student is conducting an experiment to see how long it takes to boil water. She places 5 mL of water on a hot plate and 3 L of water on a hot plate at the same temperature. When she reads the thermometer at boiling she sees that both have a temperature of 100oC.
PHYSICAL CHANGES
Physical Change: change in a substance that does not change the identity EX: Grinding, cutting, melting, boiling, tearing
Change of state: physical change that alters the state of matter EX: Boiling, freezing, condensing
STATES OF MATTER
Solid: definite volume, definite shape, particles vibrate around a fixed position
Liquid: definite volume, indefinite shape, particles flow around one another. Particles assume shape of container
Gas: indefinite volume, indefinite shape, particles move rapidly and are far apart. Fill containers completely
CHEMICAL PROPERTIES AND CHANGES
Chemical Properties: Relates to a substance’s ability to change into something else Flammability, able to rust, able to decompose, reactivity
Chemical Change: change in which a substance becomes something else Rusting, burning, rotting
CHEMICAL CHANGES ARE CHEMICAL REACTIONS (RXN)
WRITING CHEMICAL CHANGES
Reactants: substances that react in a chemical change (what you start with)
Products substances that are formed by the chemical change (What you end with)
H2 + O2 H2O
Reactants yield Products
INDICATORS OF CHEMICAL CHANGE
Color change
Gas released
Heat released or absorbed
Formation of a precipitate (solid that forms when to solutions react)
***Only way to be 100% sure is to test for the new substance
PRACTICE – PHYSICAL OR CHEMICAL CHANGEBreaking a pencil
Wood burning
Silver tarnishing
Ice melting
Hard boiling an egg
Grinding coffee beans
Burning gasoline
WARM UP – 2/6
Classify the following as chemical or physical changes
-Burning a pile of leaves
-Crushing an ice cube
-Cooking a steak
-Melting a bar of gold
MORE VOCAB
Mixtures: a blend of two or more substances that are NOT chemically combined. Each substance retains its own identity and properties. Mixtures vary in composition
Homogeneous: uniform composition throughout (SAME) Salt water, kool-aid, sweet tea
Heterogeneous: composition varies throughout (DIFFERENT) Soup, yogurt with fruit in it, bag of M&Ms
PRACTICE – HOMO OR HETERO
Stainless Steel
Granite
Air
Blood
Hand lotion
Oil and Water
Bird Seed
Chunky peanut butter
Dirt
PURE SUBSTANCES VS. MIXTURES
Pure substances have the same properties and composition everywhere Boiling point of water is the same here, in NYC, Paris, etc. Water is ALWAYS H2O, Glucose is ALWAYS C6H12O6
FANCY MIXTURES
Solution: homogeneous mixture of any phase! EX Soda, air, coffee
Suspension: heterogeneous mixture whose particles settle out over time and can be separate by filtration EX Muddy water
Colloid: special suspension whose particles don’t settle out and cannot be filtered. They scatter light (Tyndall effect) EX: Fog, milk, mayonnaise