Chemistry Exam One
2/12/96
Name______
1. Write the following numbers in correct scientific notation
A. 58.23______
B. 0.00320______
C. 62.3 x 10-1______
2. Perform the following operations and write your answer in correct scientific notation.
A. (2.78 x 10-3)(9.75 x 107)
4.5 x 102 = ______
B. (6.40 x 102)2
3.2 x 10-3 = ______
3. Round the following numbers to 4 significant figures.
A. 40.00123______
B. 0.02032______
C. 1.49998______
4. Perform the following conversions
A. 8.47 kg =______g
B. 0.263 mm = ______m
C. 7.2 s = ______s
5. A metal cube is 36 mm on each edge, and it has a mass of 326.4 g. Calculate the density of the metal in g/cm3.
6. Identify the following as physical or chemical changes
A. Melting lead______
B. caramelizing sugar______
C. dissolving salt in water______
D. Hammering a piece of gold
into a thin sheet______
E. Exploding a firecracker______
F. a piece of iron turns red when
heated______
7. Identify the following as pure substances or mixtures
A. ethyl alcohol, C2H5OH______
B. sugar dissolved in water______
C. brass______
8. Describe three differences between the solid phase and the liquid phase of a substance.
9. An experiment was performed to determine the density of the metal contained in dimes. 40 dimes were added to a graduate cylinder that contained 33.6 mL of water, and the volume in the cylinder increased to 42.0 mL. The mass of a dime is 2.63 g. What is the density of the metal in dimes? Show all calculations and formulas used. Your answer should have the correct number of significant figures.
10. Convert the following and show your conversion ratio.
A. 2.0 kg = ______lb1 kg = 2.2046 lb
B. 26 K = ______oCK = oC + 273
C. 4.3 m3 =______cm3
11. A 1.62 g sample of a metal requires 6.4 J to raise its temperature from 24oC to 43oC. Calculate the specific heat of the metal..
12. Calculate the mass of a copper cylinder having a diameter of 1.35 cm and a height of 6.46 cm. The density of copper is 8.96 g/cm3. The volume of a cylinder is V = r2h
13. Perform the following conversions showing your answers in scientific notation
A. 36.40 g = ______mg
B. 1600 g = ______kg
14. A 13.47 g piece off metal is immersed in 100 oC water for 10 minutes. The metal is then transferred to 120 g of 20.0 oC water in an insulated container. The mixture comes to a final temperature of 29.6 oC.
A. How much heat is gained by the water?
B. What is the specific heat of the metal?
15. True or False
_____ A. According to Dalton, atoms may divide into smaller particles during chemical reactions.
_____ B. According to Dalton, all atoms of a given element are identical.
_____ C. Rutherford's experiment proved that most of the mass of an atom is concentrated in its small nucleus.
_____ D. Rutherford's experiment proved the existence of isotopes of elements.
_____ E. Sulfur exists at room temperature as a diatomic molecule, S2.
_____ F. Metals are found on the left side of the periodic table.
16. Write the correct symbol for the following isotopes.
A. an atom containing 11 proton and 12 neutrons ______
B. an atom having an a mass number of 13 and an
atomic number of 7______
C. Complete the following symbol for an isotope of
carbon having a mass number of 1313C