Review for 2nd Semester Final Exam
Items discussed during the second semester of this year.
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Conversions between mass, moles, particles, and atoms
Writing and balancing chemical equations
Stoichiometry involving limiting and excess reagents
Empirical and Molecular Formulas
Boyle’s, Charles’, combined, and the ideal gas equation
Using density and atomic mass with the ideal gas equation
Partial pressures and how they relate to total pressure
Percent by mass, mole fractions, molarity (M), and molality (m)
Boiling points and freezing points
Creating and diluting solutions
What you may use on the final exam
 Periodic Table
 Your brain filled to capacity with random chemistry facts and knowledge (like the
polyatomic ions you are supposed to know, diatomic molecules, a couple of the
gas equations, and so much more…….)
 Equation Sheet
 Calculator
Sample Questions – Answer on separate sheet of paper
1. 2.50 g of propane (C3H8) reacts with 2.50 atm of oxygen gas in a 1.25 L container at
298 K producing carbon dioxide and water.
(a) Write the balanced equation
(b) Determine the initial number of moles of:
- propane
- oxygen
(c) What is the limiting reactant in the reaction?
(d) How many grams of carbon dioxide are produced in the reaction?
Reviews:
- naming compounds
- writing and balancing equations
- calculating moles using molar masses
- the ideal gas equation
- limiting reactants
- stoichiometry
2. Determine the number of atoms of H in 64.3 g of calcium hydroxide.
Reviews:
- Conversions between mass, moles, particles and atoms
3. 65.3 g of sulfur hexafluoride gas is at 15° C in a 1.95 L container.
(a) What is the formula for sulfur hexafluoride?
(b) Calculate the number of moles of sulfur hexafluoride in the container
(c) What is the pressure in the container?
Reviews:
- Naming compounds
- Converting grams to moles
- Using the ideal gas equation
4.
Ca3(PO4)2(s) ↔ 3 Ca2+(aq) + 2 PO43-(aq)
A solution is formed by dissolving 42.3 g of solid calcium phosphate, Ca3(PO4)2, in
500. mL of solution as represented by the equation above.
(a) Calculate the molarity of the solution.
(b) What mass of Ca2+ (aq) is produced?
(c) What volume of the original Ca3(PO4)2 solution is needed to form 450 mL
of a 0.10 M solution
Reviews:
- Calculating molarity
- Stoichiometry
- Diluting solutions
5. Write and balance the following reactions.
(a) A nitric acid solution is added to a solution of calcium phosphate producing
phosphoric acid and calcium nitrate.
(b) Nitrogen gas is bubbled into lithium metal producing lithium nitride.
Reviews:
- Writing chemical formulas and chemical equations
- Balancing equations
6. A 1.5 M solution of HC2H3O2 has a volume of 450. mL.
(a) Determine the percent by mass of hydrogen in the compound
(b) Determine the mass of acetic acid in the solution.
Reviews
- percent by mass
- conversions involving molarity
7. 19.3 g of N2, 54.1 g of O2, and 48.4 g of F2 are combined together in a rigid 5.67 L
container. The total pressure of the mixture is 4.98 atm.
(a) Calculate the mole fraction of O2 in the mixture
(b) Find the partial pressure of F2 in the container
Reviews
- Calculations involving mole fractions
- Using mole fractions to find the partial pressure of a gas
8. Determine the empirical formula of a compound that contains the following percent
composition data: 60.00% carbon, 13.33% hydrogen, and 26.67% oxygen.
The molecular formula has a mass of 240 g/mol, determine the molecular formula.
Reviews:
- Percent composition
- Converting empirical formulas to molecular formulas
9. Describe the steps to create 500. mL of a 3.42 M Na3PO4 solution
Reviews:
- Creating solutions
10. 0.807 g of an unknown gas at 32.0°C is contained in a 89.85. mL container at 950.
mm Hg. Calculate the density and molar mass of the gas. Is the gas CO, CO2,
CH3OH, C6H12O6, or C12H22O11?
Reviews:
- Calculating the density and molar mass of a gas
- Using the molar mass of a gas to identify the gas
11. Calculate the boiling and freezing point of the following solution: 42.3 g of N2O5 is
dissolved in 152 g of water. (Kf for water is 1.86°C/m and Kb for water is 0.51°C/m)
Reviews:
- Using molality to determine the B.P. and F.P. of a solution
12. 4.36 g of an unknown solute is dissolved in 125 g of water and is experimentally
found to have a boiling point of 103.4°C. Using the Kb from the previous problem,
determine the molar mass of the solute.
Reviews:
- Using boiling point data to determine the molar mass of a solute