Unit 7 Study Guide:
Atoms, Elements/Compounds/Mixtures, States of Matter, Physical and Chemical Properties and Changes
1. Famous scientists in the study of the atom: Name, dates, and contribution. See summary on page 203.
Date Contribution
Aristotle 425BC Earth, Air, Fire, Water, Aether
Democritus 425BC Matter is made of indivisible atoms
John Dalton 1802 Atomic Theory of Matter
Joseph Priestly 1772 Discovered Oxygen
Antoine Lavoisier 1783 1st Chemistry Textbook, L.O.C.M.
J.J. Thomson 1897 Discovered the electron
Ernest Rutherford 1909 Discovered the proton
Niels Bohr 1913 Proposed electron energy levels
Gilbert Lewis 1916 Proposed the term ‘valence’
James Chadwick 1932 Discovered the neutron
2. Using the Periodic Table to find the characteristics of an atom:
Consider Phosphorous P-15. See practice pages 211, 213, 218.
Atomic Symbol: P Bohr Model Lewis Model
Atomic Number: 15
Atomic Mass: 30.97
Protons: 15
Electrons: 15
Neutrons: 16
Group: 5
Period: 2
Electron Shells: 3
Valence Electrons: 5
Ionic State: -3
Type: non metal
Most common Isotope: P-31
3. Classifying matter; mixture or pure substance, homogeneous or heterogeneous, and compound or element.
Substance mixture/pure substance homo/hetero/compound/element
· Sand M Hetero
· Fruit punch M Homo
· Magnesium P E
· Baking Soda (NaHCO3) P C
4. Properties of matter physical or chemical
· Physical properties are the senses and measurements and can be observed without changing the substance.
· Chemical properties are reactivity, or flammability. They cannot be observed except in a chemical reaction.
Characteristic Physical Chemical
· Smell X
· Bubbles X
· Color change X
· Length X
Observation Physical Change Chemical Change
· Alka Seltzer in water X
· A melting popsicle X
· Dissolving Kool-Aid in water X
· Frying French-fries X
5. Knowing the relationship between the following terms:
Atom is to Element: an atom is the smallest part of an element that retains the characteristics of that element
Molecule is to Compound : a molecule is the smallest part of a compound that retains the characteristics of that compound
6. An intensive property versus an extensive property
Intensive: a property of a substance that does not change with the size of the sample
Extensive: a property of an object that changes with the size of the sample
Characteristic Intensive or Extensive
· Length Ex
· Density In
· Melting Point In
· Mass Ex
7. Law of Conservation of Mass
The mass of the reactants must equal the mass of the products
8. Kinetic Molecular Theory
All matter is in motion; the more heat energy added, the more kinetic energy of the particles
9. Using the L.O.C.M. to determine the mass of reactants or products
10. 18g of water are formed from 2 grams of hydrogen and 16g of Oxygen
11. 58g of NaCl are formed from 23g Na and 35g Cl.
12. Separating Mixtures. How would you separate a mixture of sand, salt, and iron filings?
Magnet for iron, dissolve salt in water, filter sand out, evaporate water to recover salt
13. Identifying state of matter, compounds, or mixtures looking at representative molecule models.
· Salt in water B
· A solid A
· A Liquid C
· A Gas D
· A compound E
· A mixture F
14. Kinetic Molecular Theory and the phases of matter. P.244
· When energy is added, molecules speed up, and spread out.
· Temperature is the measurement of the relative kinetic energy of matter.
· A solid remains at the same temperature as it melts or freezes because of its heat of fusion.
· A liquid remains at the same temperature as it boils or condenses because of its heat of vaporization.
15. Be able to calculate density to the correct number of decimals (limited to the fewest in the math), when D=M÷V
16. Solutions: The lesser part of the mixture is the solute (what gets dissolved), the greater part of the mixture is the solvent (what does the dissolving).