Chapters 1, 2, & 3 Review!
Test on Friday 
• Write the formula and charge for:
– Thiosulfate
– S2O3
2-
• Write this number down and place a check
over each significant figure.
0.0014030
How many sig figs in the number?
Ans: There are 5 significant figures
• What is the empirical formula of a molecule
containing 65.5% carbon, 5.5% hydrogen, and
29.0% oxygen?
• Ans: C3H3O
• Give an example of a heterogeneous mixture
• Ans: Chicken Noodle Soup 
• Write the formula for the following
compound
– Vanadium (III) Chloride
– Ans: VCl3
• What is the definition of an isotope?
• Ans: Two or more forms of the same element
that contain equal number of protons and
different number of neutrons
• Calculate the percent of water in
Zinc Sulfate Heptahydrate
Ans: 43.86%
• How many moles are in a sample of NaCl that
weighs 11.62g?
• Ans: 0.1988 mol NaCl
• A 0.1005 g of menthol (a compound
containing carbon, hydrogen and oxygen) is
combusted, producing 0.2829 g of CO2 and
0.1159 g of H2O. What is menthol's empirical
formula?
• Ans: C10H20O
• Write the formula for the following
compound
– Ammonium Sulfate
– Ans: (NH4)2SO4
• What is the oxidation number of Phosphorous
in PO43-
Ans:
+5
•
?
• When a 10.0 gram sample of an unknown organic acid
(containing C, H, and O) is subjected to combustion
analysis, 21.2 grams of carbon dioxide and 3.25 grams of
water are produced. What is the empirical formula of the
acid?
Ans: C4H3O2
• If the molecular mass is found to be near 166 grams/mol,
what is the molecular formula?
– Ans: C8H6O4
• Name the following compound:
– Fe3(PO3)2
– Ans: Iron (II) Phosphate
• A 5.018 gram sample of a certain hydrate of
magnesium sulfate, MgSO4•xH2O, is heated
until all the water is driven off. The resulting
anhydrous compound weighs 2.449 grams.
What is the formula of the hydrate?
• Ans: MgSO4 . 7H2O
• Write the formula for the following
compound
– Nitrogen Dioxide
– Ans: NO2
• Name this compound:
– CuSO4∙5H2O
– Ans: Copper (II) Sulfate Pentahydrate
• Compare and contrast empirical and molecular
formula.
• Ans:Empirical is the simplest formula with the
lowest whole numbers possible. Molecular
formula would be some multiple of the Empirical
• Name the following compound:
– N2S3
– Ans: Dinitrogen Trisulfide
• What is the oxidation number of Iron in Fe2O3
•
Ans: +3
• Write the formula for the following
compound
– Phosphorous Acid
– Ans: H3PO3 (aq)
• What is the percent by mass of Nickel in
Nickel (II) acetate tetrahydrate?
• Ans: 23.58%
• What is the percent composition of C5H10O?
• Ans: 69.70%C, 11.72%H, 18.57%O
• Name the following compound:
– HCl (aq)
– Ans: Hydrochloric Acid (would be hydrogen
chloride gas WITHOUT the aq. With the aq it is an
ACID!)
• How many atoms of Hydrogen are present in 8.0g of
water?
• Ans: 5.35x10^23
– (take grams of water, to moles of water, to moles of
hydrogen (how many moles of hydrogen are in one mole
of water?), and then take to atoms of hydrogen with
avagadro’s number)
• Name the following compound:
– HMnO4
– Ans: Permanganic Acid