Atomic Structure: Chpt. 4 Atom Robert Milliken Democritus J.J Thomson John Dalton James Chadwick...
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Transcript of Atomic Structure: Chpt. 4 Atom Robert Milliken Democritus J.J Thomson John Dalton James Chadwick...
Atomic Structure: Chpt. 4•Atom Robert Milliken•Democritus J.J Thomson•John Dalton James Chadwick•Dalton’s Atomic Theory Ernest Rutherford •Protons•Electron•Neutrons•Cathode Ray•Eugen Goldstein
Objectives:
1. I can classify matter into substances and mixtures.2. I can identify and distinguish between physical and
chemical properties. 3. I can identify and distinguish between the two types of
forces that affect the nature of molecules. 4. I can understand and distinguish between physical and
chemical changes. 5. I can identify techniques used to separate mixtures.
Daily Objective
• I can define matter. • I can identify and distinguish between the
classes of matter.
What do all matter have in common?Atoms!
What is Matter?
• One or more atoms that take up space and has mass.
• Emphasized that all matter’s properties and changes are due to the chemical make-up and interactions on the atomic level.
Classifying Matter:Substances vs. Mixtures
Substances•Definite chemical make-up•Elements or compounds•Ex. Silicon chip or H2O
Mixtures•Varied chemical make-up• 2 or more substances physically combined•Homo or Hetero Mixtures• Pizza and salt water
Classifying Matter:Substances vs. Mixtures
Element•Pure and simplest substance•One type of atom•Periodic table•Symbol, (He= Helium)
Homogenous Mixture•2 or more substances physically combined.•Substances are very soluble in one another-mix well – one phase•Substances in mix properties are preserved•Separated by physical processes.•Also called a solution•Ex. salt water, kool-aid
Compound• 2 or more substances chemically combined•Definite composition•Break-down only thru chemical processes•Substances making up cmpd gain new properties.•Chemical Formula, H2OEx. iron rust
Heterogenous Mixture•2 or more substances physically combined.•Substances are not soluble in one another-do not mix well-multiple phases•Substances in mixture properties are preserved.•Separated by physical processes•Ex. Oil and water, pizza, soil
Compounds:
Compounds = Chemical Combination of elements in fixed amount.
Ex. Sodium Chloride (salt) NaCl
Sodium (Na) + Chlorine (Cl) = Salt (NaCl)
Heterogenous MixuresObserve multiple phases or parts because substances do not mix well.
Homongenous Mixtures• Also called solutions.
• Solutions:
-Solute: what is dissolved
-Solvent: what dissolves
Solubility= the ability of the solute to dissolve in the solvent.
.
Bell Ringer: Matter1. What is matter?
2. What is the difference between:
a. substances and mixtures
b. compounds and mixtures
3. Classify each of the following examples:
a. sugar
b. sugar water
c. gold ring
d. Iron rust (FeO)
e. Italian dressing
Classifying Matter• one kind of atom• physical combination of substances• multiple phases• one phase• chemical combination of substances• same chemical make-up from sample to sample• properties are preserved when substances combine• varied chemical make-up from sample to sample• properties change when substances combine• oxygen (O2)
• muddy water• limestone (CaCO3)
• tap water
Classifying Matter Lab
• Students with peers observed various samples of matter and classified them as an element, compound, homo mixture, or hetero mixture.
Classifying Matter1. Classify each as either an element, compound,
homo mixture, or hetero mixture
a. soil
b. orange juice with no pulp
c. copper wire
d. car gasoline (C8H18)
2. What is the difference between a compound and a mixture?
Chemical Changes• A chemical process
• Substance(s) chemical make-up is changed producing new substances.
• New properties are observed.
Ex. Iron Rust (FeO)
Intramolecular Forces
H2O compound
Forces within a compound that holds the atoms together. Also called chemical bonds.
Types of Chemical Changes• Combustion• Decaying• Digesting• Baking• Neutralization (acidic and basic chemicals)• Growing• Spoiled
Physical Changes • Physical process
• Substance(s) chemical make-up is preserved so no new substance is produced.
• Properties are preserved
Ex. Making Lemonade
Physical vs. Chemical Changes
• Re-assess Chemical and Physical Change Lab
• Homework: Physical vs. Chemical Change Worksheet
Mixture Separation Lab• Students work in groups to determine what
physical processes they can use to separate out each substance in a given mixture.
• They will design and carry out their experiment to successfully separate out each substance in the mixture.
• Reiterate the concept that substances in a mixture maintain their physical properties because their chemical make-up is preserved.
Mixture Separation Lab
• What physical properties did you use to separate the substances in the mixture?
Homongenous Mixtures• Also called solutions.
• Solutions:
-Solute: what is dissolved
-Solvent: what dissolves
.
Mixture Separation Lab
• What physical properties did you use to separate the substances in the mixture?
Physical Separation of Mixtures:Extraction
1. Extraction- separating substances in a heterogenous mixture from one another based on their unique physical properties..
Physically separate oil from water because they are not soluble in one another.
How could we separate iron fillings and sand?
Solubility of Mixtures
Chemistryland.comSciencephoto.com
Solubility: How well substances physically combine.
Physical Separation of Mixtures:Filtration
Commonly used to separate a solid from a liquid in a heterogenous mixture due to differences in size or solubility.
Physical Separation of MixturesDistillation
Separation of liquids in a mixture by their differences in boiling points. Ex. Ethanol (78 0C) and Water (1000C)
Chromotography• Separates homogenous mixtures based on solubility.
• Chromotography has two phases:
-Stationary Phase: solid
Mobile Phase: liquid or gas
• Substances in mixture will separatebased on their degree of solubility toward the mobile phase.
Physical Separation TechniquesSeparation Technique
HeterogenousMixture
HomogenousMixture
What physical properties are used?
Filtration
Extraction
Distillation
Chromotography
Matter and Energy
I can….• Establish a relationship between changes
in matter, the forces involved, and the flow of energy.
Phase Change Processes
A. Melting
B. Freezing
C. Evaporation
D. Condensation
E. Sublimation
F. Deposition
G. Ionization
H. Deionization
Particles in Matter• The particles that make-up matter are in
constant motion.• The particles speed of motion depends upon?
Heat Energy Heat Energy = Energy that is transferred between
matter of different temperatures. (joules/calories)
• How does heat energy move between objects?
Heat Energy Flow:• System: matter you are studying/measuring• Surrounding : environment around the system
• Endothermic Process: heat ______by system• Exothermic Process: heat ________by system
(released or absorbed)
Heat Energy• Heat energy alters the:
-speed of particles
-strength of the intermolecular forces
Heat Energy
Temperature Scales
Visionlearning.com
Temperature only measures the heat energy that alters the speed of particles.
Molecular Kinetic Theory
Heat Energy
OC
Establishes a relationship between physical changes, intermolecular forces, and energy flow.
Conservation of Matter and Energy
Matter:Matter undergoes changes, but the atoms are conserved as a whole or as parts.
Energy:Energy is also conserved during changes that matter undergoes. If energy increases for a system, then its surroundings must decrease in energy by the same amount.
Heat Capacity
Heat Capacity:
The amount of heat needed to raise the temperature of a substance 1.0 oC.
What does heat capacity depend upon?
Specific Heats of Common Substances
Substances Specific HeatJ/g* 0C
Specific HeatCal/g*0c
water 4.18 1.00
Grain alcohol 2.4 0.58
ice 2.1 0.50
steam 1.7 .40
aluminum 0.90 0.21
silver 0.24 0.057
mercury 0.14 0.033
Specific Heat CapacitySpecific Heat Capcity:
The amount of heat it takes to raise 1g of the substance 1 0C.
Heat Calculation
• The temperature of a 95.4 g piece of copper increases from 25.0oC to 48.0oC when the copper absorbs 849 Joules of heat. What is the specific heat of copper?
Heat Calculations
• How much heat is required to raise the temperature of 250.0g of mercury to 52oC?
Bell Ringer1. What is the difference between heat energy (q) and
specific heat energy (C)?
2. When 150.0 J of energy is absorbed by a 42.1 g sample of silver the temperature increases by 15.0oC. What is the specific heat of silver?
3. If an 8.8 gram sample of aluminum increases in temperature from 25oC to 55oC how much heat was absorbed by the aluminum sample?