Naming Compounds and Chemical Composition

Naming Compounds

• The first element in the compound retains its original name.
• The second element receives the suffix "-ide".
  • Carbon becomes carbide.
  • Oxygen becomes oxide.
  • Phosphorus becomes phosphide.
• Prefixes are added to indicate the quantity of each element.
  • One: Mono
  • Two: Di
  • Three: Tri
  • Four: Tetra
  • Five: Penta
  • Six: Hexa
  • Seven: Hepta
  • Eight: Octa
  • Nine: Nona
  • Ten: Deca
• The prefix "mono" is omitted for the first element.

Examples:

• Carbon Dioxide (CO_2)
  • Carbon: No prefix, implying one carbon atom.
  • Oxygen: "Di" prefix indicates two oxygen atoms, named oxide.
• Carbon Monoxide (CO)
  • Carbon: One carbon atom, no prefix.
  • Oxygen: One oxygen atom, named monoxide.
• Dihydrogen Monoxide (H_2O) (Water)
  • Hydrogen: "Di" prefix indicates two hydrogen atoms.
  • Oxygen: "Mono" prefix indicates one oxygen atom, named monoxide.
• Diphosphorus Pentoxide (P2O5)
  • Phosphorus: "Di" prefix indicates two phosphorus atoms.
  • Oxygen: "Penta" prefix indicates five oxygen atoms, named oxide.

Acids

• Acids involve a relationship between hydrogen and a nonmetal anion.
• Acids must contain hydrogen.

Binary Acids

• Composed of hydrogen and a single element.
  • Examples: HCl, HBr, H2S, H3P.
• Naming Convention:
  • Start with "hydro-".
  • Add the element's root name.
  • End with "-ic acid".
  • The "hydro-" prefix indicates the element stands alone, bonded to hydrogen only.
  • HCl: Hydrochloric acid (chlor- from chlorine).
  • HBr: Hydrobromic acid (brom- from bromine).
  • H_2S: Hydrosulfuric acid (sulf- from sulfur).

Oxoacids

• These acids contain oxygen. They are derived from polyatomic ions.
• Important Anions to Remember: Sulfate (SO4^{2-}, Carbonate (CO3^{2-}, Phosphate (PO4^{3-}, Nitrate (NO3^{-}$)
• "-ate" Suffix Rule: When the anion name ends in "-ate", replace it with "-ic acid".
  • Sulfate (SO4^{2-}) becomes sulfuric acid (H2SO_4).
  • Carbonate (CO3^{2-}) becomes carbonic acid (H2CO_3).
  • Phosphate (PO4^{3-}) becomes phosphoric acid (H3PO_4).
  • Nitrate (NO3^{-}$) becomes nitric acid (HNO3).
• If the compound contains oxygen, there is no "hydro" prefix.

Naming acids - Examples

• H2SO4: Sulfuric acid (sulfate ion).
• H2CO3: Carbonic acid (carbonate ion).
• HBr: Hydrobromic acid (binary acid).
  • "Hydro" prefix means hydrogen and the element alone.

Chemical Composition - Chapter 6

• Counting by Measuring
  • Pair = 2
  • Dozen = 12

The Mole

• A mole is a unit of measurement.
• 1 mole = 6.02 \times 10^{23} (Avogadro's number).
• Avogadro's Number: 6.02 \times 10^{23}. It's the number of atoms, molecules, or particles in one mole of a substance.
• 1 mole of carbon-12 contains 6.02 \times 10^{23} atoms and weighs 12 grams.

Molar Mass

• The mass of one mole of a substance, usually expressed in grams per mole (g/mol).
• Molar Mass Equation: \text{Molar Mass} = \sum \text{Atomic Weights}
• To find molar mass, sum the atomic weights of each element in the chemical formula.
• The atomic weight is the number with a decimal found on the periodic table.

Calculating Molar Mass - Example

• Water (H_2O)
  • Hydrogen (H): 1.008 g/mol (x2 = 2.016 g/mol).
  • Oxygen (O): 16.00 g/mol (x1 = 16.00 g/mol).
  • Molar Mass of Water: 2.016 + 16.00 = 18.016 g/mol.

Calculating Molar Mass - Example

• Sodium Chloride (NaCl)
  • Sodium (Na): 22.99 g/mol
  • Chlorine (Cl): 35.45 g/mol
  • Molar mass of NaCl: 22.99 + 35.45 = 58.44 g/mol.

Mole Conversions

• Moles can be expressed using:
  • Avogadro's Number: 1 mole = 6.02 \times 10^{23} atoms/molecules/particles.
  • Molar Mass: 1 mole = X grams (where X is the molar mass of the substance).
• These equalities can be written as fractions for dimensional analysis.

Dimensional Analysis Reminder

• Given number and unit → Conversion factors → Desired unit.

Mole Conversion - Example

• How many grams of lead (Pb) are in 2 moles of lead?
  • Given: 2 moles of Pb.
  • Molar mass of Pb: 207.2 g/mol (from the periodic table).
  • Conversion: 2 \text{ mol Pb} \times \frac{207.2 \text{ g Pb}}{1 \text{ mol Pb}} = 414.4 \text{ g Pb}

Mole Conversion - Example

• How many moles of lead (Pb) are there in 3.4 grams of lead?
  • Given:3.4 g of Pb
  • Known: Molar Mass Pb = 207.2 g/mol
  • 3.4 g Pb * \frac{1 mol Pb}{207.2 g Pb} = 0.016 \text{ mol Pb}

Two-Step Conversions

Grams can be converted to moles using molar mass, and moles can be converted to atoms/molecules using Avogadro's number, and vice versa.

Multi-Step Conversion - Example

• How many atoms are there in 3.4 grams of lead?
• 3.4g Pb → moles of Pb → Atoms PV
  • Given 3.4 grams of lead, PV is 207.2g
    3.4 g Pb * \frac{1 mol Pb}{207.2 g Pb} * \frac{6.02 \times 10^{23} atoms Pb}{1 mol Pb} = 9.9 \times 10^{21} atoms Pb