Chemistry Class on Chemical Formulas

Chemical Formulas and Nomenclature

• The iodate ion has the formula IO3-.
• The name of (NH4)2HPO3 is ammonium hydrogenphosphite.
• AgNO3 is used medically as an antibiotic.
• Bromous acid has the formula HBrO2.

Electron Configuration

• The ground state electron configuration of the most stable ion that Rb forms is [Kr]5s24d105p6.
• The ground state electron configuration of the most stable ion that I forms is [Kr]5s24d105p6.

Atomic Structure and Isotopes

• Barium-138 forms a stable ion with 56 protons, 54 electrons and 82 neutrons.
• Phosphorus-31 forms a stable ion with 15 protons, 18 electrons and 16 neutrons.

Chemical Compounds

• Hydrogen fluoride is represented by the formula HF(g).
• The name of O2F2 is dioxygen difluoride.
• Chromium(VI) carbonate has the formula Cr(CO3)3.

Molecular Geometry and Polarity

• The CH2O molecule has a trigonal planar shape around the central atom with an approximate bond angle of 120.0 degrees. It contains polar bonds.
• The correct Lewis structure for CH3Cl shows the carbon atom with three single bonds and one single bond. It is a polar molecule with a tetrahedral shape and an HCH bond angle of approximately 109.5 degrees.
• C2F4 is a nonpolar molecule with polar bonds.

Formula Weight and Stoichiometry

• The formula weight of Cr2(SO3)3 is 392.21 amu.
• 0.315 mol of Cr2(SO3)3 corresponds to 124 g of Cr2(SO3)3.
• 7.02 x 10^22 formula units of Cr2(SO3)3 contain 3.75 g of sulfur.

Balancing Chemical Equations

• The balanced equation for the combustion of C7H14 is 2C7H14 + 21O2 → 14CO2 + 14H2O.

Redox Reactions

• In the reaction Cu2+(aq) + Zn(s) → Cu(s) + Zn2+(g), Zn(s) is oxidized and is the reducing agent, while Cu2+(aq) is reduced and is the oxidizing agent.

Limiting Reactant and Percent Yield

• In the reaction 2 H2(g) + 2 NO(g) → N2(g) + 2 H2O(g), with 31.8 g of H2(g) and 127.1 g of NO(g) reacting to produce 22.8 g of N2(g), the limiting reactant is NO.
• The percent yield for the reaction is 61.6%.
• To form 220.6 g of N2(g), 31.8 g of H2(g) is required.

Thermochemical Equations

• The production of 156.0 g of iron according to the thermochemical equation Fe2O3(s) + 196.5 kcal → 2 Fe(s) + 3/2 O2(g) consumes 548.9 kcal of energy and is an endothermic reaction.

Fluoride and Tooth Enamel

• Fluoride ions replace hydroxide ions in hydroxyapatite, forming the less acid soluble fluoroapatite, thereby protecting the enamel against tooth decay.

Test your knowledge on chemical formulas, nomenclature, electron configurations, atomic structure, and molecular geometry. This quiz covers various aspects of chemistry, including the naming of compounds and the properties of ions. Perfect for chemistry students looking to reinforce their understanding.