CHEM 2100Homework

CHEM 2100Homework #1 Due: Wednesday February 10th by 11:59 p.m.

NAME: (46 points)

(1) (4 pts) Indicate the correct number of significant figures for the following numbers:

204 _______________

0.0089802 _______________

3.020 x 10?9 _______________

1000 _______________

670.0 _______________

88 _______________

0.106010 _______________

2180. _______________

(2) (4 pts) Perform the following calculations reporting the final answer with the correct number of significant figures.

354.23 + 48.782 +98.67902 _____________

8.864 6.2 + 24.26 _____________

89.127 x 5.37 _____________

100.21 x 0.38 _____________

5018/17.252 _____________

(4.47 x103 + 1.6 x 102)/8.54234 x 105 _____________

(0.971 0.43)/(8.1 + 65.176) _____________

(3288/64.86) + (26.0 x 9) _____________

(3) (2 pts) In a piece of scientific equipment is it better to be precise or accurate? Defend your answer.

(4) (5 pts) According to the world atlas Rhode Island is the smallest US state with a land area of 1,033.81 square miles. If it rains on the entire state a total of 2.5 inches how many liters of water fell as rainfall? If one raindrop is 0.50 mL how many individual raindrops fell?

(5) (5 pts) The top cruising speed of the SR-71 Blackbird was Mach 3.17 or 2,432.24 miles per hour. How many minutes would it take the Blackbird to fly from San Bernardino, CA to New York City? A distance of 4,417.81 kilometers.

(6) (4 pts) A kilogram of solid Platinum costs $30,993.32. If the density of Platinum is 21.45 g/cm3 what would the dimensions of a cube be that weighed 1.00 kilogram?

(7) (4 pts) Indium (In) consists of two main isotopes, 113In (112.904058 amu) and 115In (114.903878 amu). If the atomic weight of In is 114.818 amu what are the relative abundances of the two isotopes? [Report your answers to 2 decimal places]

(8) (4 pts) Zinc consists of 5 main isotopes. 64Zn at 48.63%, 66Zn at 27.90%, 67Zn at 4.10%, 68Zn at 18.75%, and 70Zn at 0.62%. Using the isotope masses found in the table below calculate the atomic mass of Zinc.

Isotope

Mass, amu

64Zn

63.9296011

66Zn

65.9260368

67Zn

66.9271309

68Zn

67.9248476

70Zn

69.925325

(9) (2 pts) Indicate whether the following ions have a noble-gas electron arrangement.

Ti3+ ______________

Mn7+ ______________

Pb3+ ______________

As3? ______________

(10) (4 pts) Give the correct name for the following compounds.

Fe2(CO3)3 __________________

S4O10 __________________

KMnO4 __________________

H2S __________________

N2O5 __________________

PbCl2 __________________

Ag2Cr2O7 __________________

HClO __________________

(11) (4 pts) Give the correct chemical formula for the following compounds.

Sodium hypobromite ___________

Chromium (III) acetate ___________

Chloric acid ___________

Dinitrogen tetroxide ___________

Cobalt (II) hydrogen carbonate ___________

Zinc Nitrate ___________

Ammonia ___________

Ammonium __ ________

(12) (4 pts) Fill in the missing pieces of the following table:

Symbol

31P3?

Protons

Neutrons

Electrons

Mass #

Net Charge

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