PowerPoint created during the Exam Prep session held 9/24/17 from Chemistry 107 offered at TAMUG

1. Chemistry 107 Test 1

2. Chapter 1
- States of Matter
- Prefixes/units
- Conversions
○ Temperature
○ Unit
- Sig Fig rules
- Density
- Problem Solving

4. Significant Figures

5. Errors
Random Error-an error in measurement caused by factors that vary from one measurement to another.
Systematic Error-are reproducible inaccuracies that are consistently in the same direction.

6. Chapter 2 - Atoms and Molecules
Atom composition/symbol
● What is the atomic mass?
Isotopes
Periodic Table
Ionic Compounds
● Transfer of electrons
Covalent
● Shared electrons
Nomenclature
Chemical Formulas
Functional Groups

7. Isotope Abundance
The element gallium has atomic weight of 69.72 amu. There are only two isotopes
of gallium, 69Ga with a mass of 68.9257 amu and 71Ga with a mass of 70.9249
amu. What are the isotopic abundances of gallium?
Ans: 60.1% of 71Ga and 39.9% of 69Ga

8. Ionic vs. Covalent
Ionic: metal + nonmetal
● Ex. Sodium Chloride (NaCl)
Covalent: nonmetal + nonmetal
● Ex. Carbon Monoxide (CO)
Practice Naming compounds and writing chemical formulas

9. Chemical Formulas
Empirical Formula-a formula giving the proportions of the elements present in a compound but not the
actual numbers or arrangement of atoms.
Molecular Formula- a formula giving the number of atoms of each of the elements present in one
molecule of a specific compound.

10. How to name
compounds

11. Chapter 3 - Molecules, Moles and Chemical Equations
Chemical Reactions what are they?
- I. How do you know when a reaction has taken place
- Ex. Color change, Gas evolution, Heat released
Give an example of some chemical reactions that take place throughout a
typical day.
Hand Warmer 4Fe(s) + 3O2(g) -> 2Fe2O3(s)

12. Types of Chemical Reactions
1. Combination Reactions - Where two reactants combine to form a
single product
- A + B AB Ex. Na+ + Cl- NaCl(aq)
1. Decomposition Reactions - Where a single product decomposes into two
products
- AB A + B Ex. NaCl(aq) Na + + Cl-

13. Types of Chemical Reactions
3. Single Displacement Reaction - When a single reactant takes the place
of another element in a compound
- A + BC B + AC Ex. Fe2O3(s+ 2Al(s) Al2O3(s)+
2Fe(s)
4. Double Displacement Reaction - When two elements from separate
compounds swap places
- AB + CD AD + CB Ex.
This is the chemical reaction of
a thermite explosive

14. Types of Chemical Reactions
5. Combustion Reaction - When reactants plus oxygen form CO2 and
products
- Ex. (2C6H6 + 15O2 ---> 6H2O + 12CO2) This the reaction of Napalm used in
Vietnam
6. Neutralization - Involves an acid and a base canceling each other out
and forming water
- Ex. HCl + NaOH NaCl + H2O

15. Chemical Symbols & Law of Conservation of Mass
- Chemical States
- (S) - Solid - (∆) Heat - Thermal Reaction, Change in heat
- (l) - liquid - (hv) Light - Photochemical Reaction
- (g) - Gas
- (aq) - aqueous
- Conservation of Mass - You will not create any new atoms nor will you lose
any atoms aka pay attention to your coefficients

16. Avogadro's Number
- Mol, not the things that crawl under the ground, but the amount of atoms per
unit of an element
- 1 mol = 6.022x10^23 atoms
- 1 mol of Carbon = 6.022x10^23 atoms
- 1 mol of Nitrogen = 6.022x10^23 atoms
- 1 mol of Xenon = 6.022x10^23 atoms
- 1 mol of Oxygen = 6.022x10^23 atoms
- I think you might get the point, no matter what the element is, 1 mol of something is equal to 1
mol of something else in terms of ATOMS

17. Conversion
Mass to Moles to
particles
- Know how to convert from these three units
- 28.5mol of P4O10 contains how many moles of P?
55g of O2 x amount of mols x amount of atoms

18. Reactions in Aqueous Solutions
- Solvent - The liquid or medium that is dissolving Ex. Water
- Solute - The compound added to the medium which dissolves Ex. Kool Aid
Packet
Electrolytes - A compound that dissociates and the dissociated particles
conduct electricity Ex. Gatorade has Sodium, Potassium, and Chloride
added to it help with muscle function
- NonElectrolyte - may dissolve, but not into ions Ex. Sugar into Water
- Weak Electrolyte - partially dissolve in ions in solution
- Strong Electrolyte - completely dissolve into ions in solution Ex. Salt

19. Net Ionic Equations
Example:
NaCl(aq)+AgNO3​(aq)→NaNO3​(aq)+AgCl(s)
Na+​(aq)+Cl−​(aq)+Ag+​(aq)+NO3−​(aq)→Na+​(aq)+NO3−​(aq)+AgCl(s)
Cl−(aq)+Ag+(aq)→AgCl(s)

20. Aqueous Solution Concentrations
- Molarity = Moles / L of Solvent
- Dilution - Taking a known concentration of a solution and adding more solvent
to lower the concentration.
- M1 V1 = M2 V2 Ex. If I take 1L of 1M Hcl and add 1L of water the new concentration is
.5M
- Ex. You have 87 mL of .500M stock solution that must be diluted to 0.100M.
Assuming the volumes are addictive, how much water should add?

21. Percent Composition
- Percent composition is used to determine the % weight that a specific
element makes in a compound
C6H12O6
C% = ?
H% = ?
O% = ?

22. Balanced Equations
The total number of atoms are the same on each side.