2H

Page 1

  • A 3.00 L bottle weighs 1.70 kg.

  • When filled with wine, it weighs 4.72 kg.

  • The wine contains 11.5% ethanol by mass.

  • Calculate the grams of ethanol in 250.0 mL of this wine.

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Page 3

  • A reaction of 0.406 g magnesium with oxygen produces 0.674 g magnesium oxide.

  • Calculate the mass of oxygen consumed in the reaction:

    • Reaction: Mg + 1/22 Mg → 0.4063 + x

    • 0.6743 - 0.4063 = 0.2683 g for oxygen consumed.

Page 4

  • In an experiment, 2.18 g of sodium reacts with 16.12 g of chlorine.

  • All sodium is consumed resulting in 5.54 g of sodium chloride (table salt).

  • In a second experiment, 2.10 g of chlorine reacts with 10.00 g of sodium.

  • All chlorine is consumed yielding 3.46 g of sodium chloride.

  • Demonstrate that these results adhere to the law of definite proportions.

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Page 6

  • Data obtained for compounds formed between nitrogen and hydrogen:

    • Nitrogen:

      • Mass 1 (g): 0.500

      • Mass 2 (g): 0.108

    • Mass 3 (g): 1.000

    • Mass 4 (g): 0.0720

    • Mass 5 (g): 0.750

    • Mass 6 (g): 0.108

Page 7

  • Calculating ratios for compound formation:

    • Example calculations for different ratios involving nitrogen and hydrogen.

Page 8

  • The standard for atomic masses is based on Carbon-12.

  • Carbon's atomic mass appears as 12.011 due to natural isotopes.

    • Carbon-12 is the standard, but Carbon-13 is also present in nature.

  • Average atomic masses take into account the natural abundance of isotopes.

Page 9

  • Silver has two natural isotopes with the following abundances:

    • 51.84% of 107 Ag

    • 48.16% of 109 Ag

  • Given 107 Ag's mass of 106.905092, calculate the mass of 109 Ag:

    • Use the equation Ag = 107.87.

Page 10

  • Properties of the periodic table:

    • Elements are organized by increasing atomic number.

    • Similar elements are grouped vertically.

    • Group examples: Sodium and Potassium in Group 1.

    • Chlorine is located in Group 17 (Halogens).

Page 11

  • Group 1: Alkali metals

  • Period 3:

  • Group 17: Halogens

Page 12

  • Elements are classified into metals and nonmetals.

    • Metals are generally solid at room temperature (except mercury).

    • Nonmetals exhibit opposite properties to metals (e.g., poor electrical conductivity).

Page 13

  • Noble gases and metalloids are small element groups in the periodic table.

    • Periods are horizontal arrangements of the periodic table.

    • First period contains just Hydrogen and Helium.

Page 14

  • Group number identification can vary:

    • Newly adopted IUPAC numbering system (1-18).

    • Older American notation with letters and numbers.

Page 15

  • Each element is represented in boxes:

    • Element symbol, atomic number (above), and average atomic mass (below).

    • Some tables include other properties (e.g., density).

Page 16

  • The periodic table organizes elements by atomic number:

    • Each group shares similar physical and chemical properties.

    • Classification includes metals, nonmetals, metalloids, and noble gases.

Page 17

  • Concept of moles and Avogadro's number:

    • Avogadro's number: 6.02214 x 10^23.

    • Represents the number of units in one mole of a substance.

Page 18

  • The mole concept is frequently used in calculations.

  • For example: 1 mol of sulfur (S) = 6.022 x 10^23 atoms = 32.065 g.

Page 19

  • Avogadro's number relates to atomic quantities in moles:

    • 1 mole indicates the number of units in a particular elemental mass.

Page 20

  • Example weights of different atoms for 6.02214 x 10^23 atoms:

    • Fluorine (F): 18.9984 g

    • Chlorine (Cl): 35.453 g

    • Magnesium (Mg): 24.3050 g

    • Lead (Pb): 207.2 g

Page 21

  • Calculate the number of Cu atoms in a silver alloy weighing 33.24 g:

    • Sterling silver contains 92.5% silver by weight.

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Page 23

  • A graduated cylinder filled halfway with 8.0 g of diatomaceous earth, mostly composed of silica.

  • Calculate the volume of water needed to fill the cylinder to the 100.0 mL mark:

    • Density of diatomaceous earth is 2.2 g/cm³.