CHEM 1364 Test 1 Spring 1998

1. A(n) _____________ is a unifying principle that explains a collection of facts.

2. A(n) _____________ consists of two or more atoms that are connected.

3. ________________ is the ratio of mass to volume for a substance.

4. The ________________ in a chemical reaction has it's atoms rearranged to form a new substance.

5. A(n) ________________ chemical equation is a description of what happens during a chemical reaction, accounting for each atom involved.

6. ________________ occurs because of the random motion of molecules, and was demonstrated in class by dropping green food coloring into a beaker of water.

7. A(n) _________________ occurs when there is no apparent change in the number of atoms or molecules involved in a process, such as occurs in a saturated solution of sodium chloride.

8. The ___________ of an atom is an incredibly small volume of the atom that contains all of the positive charge and virtually all of the mass of the atom.

9. _____________ are atoms of the same element with different masses.

10. A(n) _________ is simply a particle with either an excess or a deficiency of electrons.

11. A(n) _________ is Avogadro's Number of particles.

12. The _______________ formula of a compound is the smallest whole number ratio of atoms that make up the compound.

13. __________________ analysis for an unknown is performed by burning a sample of the unknown, and determining the amount of carbon dioxide and water that is released.

14. Another name for a homogeneous mixture is a(n) ___________________.

15. Dilution is the process of adding _________________ to a solution.

16. (15) Perform the following conversions.

a) 479 mi to km (Air distance from Lawton to Memphis; 2.54 cm = 1 in)

b) The volume of 75.0 g of mercury (d_Hg = 13.6 g/mL)

c) The area of a 10.0 acre lot in m² (1 acre = 4840 yd²; 2.54 cm = 1 in)

17. (15) Provide the missing name or formula:

Ammonium nitrate ______________

_________________________ AlPO₄

Copper(II) sulfate pentahydrate _______________

_________________________ P₂O₅

Iron(III) oxalate _______________

18. (15) Calculate the mass of caffeine in a typical 8.00 oz cup of coffee. Caffeine has a chemical formula of C₈H₁₀N₄O₂, and the concentration of caffeine in coffee has been determined to be 2.80 x 10^-3M for coffee from the Student Union. [1 oz = 29.574 mL]

19. (15) Determine the empirical and molecular formula of a substance that is 92.25%C and 7.75%H, and has a molecular weight of 78.11

20. (10) Calculate the molarity of a solution prepared by dissolving 5.00 g of ethanol (C₂H₆O) in enough water to make a solution of 125 mL.

EXTRA CREDIT (10) What mass of carbon dioxide can be prepared from the combustion of 10.0 g of propane. The reaction is: C₃H₈ + 5O₂ 3CO₂ + 4H₂O

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