Chemistry Practice Exam #1
1)
Do the following conversions:
a) 54.2 cm3 to in3
(1 in = 2.54 cm)
c) 0.87 g/mL to lb/quart
(1 lb = 453.6 g; 1 quart = 0.946 L)
b) 2.734 x 10-2 nm to cm
d) 8.6542 x 107 mg to kg
e) 2.867 x 10-9 L to L
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2)
Perform the following mathematical operations and express the results to the correct number of
significant figures:
a) 7.8132 + 0.6 + 18.24
b) (1.34 x 10-3)x(9.1 x 10-6)
3)
Answer the following True or False:
a) The identity of an atom is determined by the number of electrons it has.
b) Copper (II) chloride is an ionic compound
c) Different isotopes of a given element have different masses.
d) The melting of ice is an example of a physical change.
e) Density is an example of a physical property of a substance.
4)
Co 3 has:
a) 27 protons, 27 electrons, 59 neutrons
59
27
b) 22 protons, 27 electrons, 37 neutrons
c) 27 protons, 27 electrons, 32 neutrons
d) 27 protons, 30 electrons, 32 neutrons
e) 27 protons, 24 electrons, 32 neutrons
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5)
Give the formulas of the following compounds:
a) Lithium oxide
b) Dinitrogen tetroxide
c) Iron (III) hydroxide
d) Aluminum sulfate
e) Chloric acid
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6)
Give the names of the following compounds:
a) Na2SO4
b) CuS
c) SO2
d) (NH4)2CrO4
e) Hydrobromic acid
7)
a) Gallium has two naturally occurring isotopes, 69Ga (with a mass of 68.9256 amu and a natural
abundance of 60.11%) and 71Ga (with a mass of 70.9247 amu and a natural abundance of 39.89%).
Calculate the average atomic mass of gallium, showing all your work.
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b) If 1 gram is 6.022 x 1023 atomic mass units (amu), calculate the mass in grams of one atom of 69Ga.
8)
Balance the following chemical equations:
a) HI + As2S3  AsI3 + H2S
b) Fe + O2  Fe2O3
c) HBr + KOH  KBr + H2O
d) Cs + H2O  CsOH + H2
e) C2H6O + O2  CO2 + H2O
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