Unit 6

On completion of the unit you should be able to:

1. balance chemical equations.
2. interpret balanced equations in terms of moles, mass units and number of particles.
3. given the number of moles (or mass or number of particles) of one substance calculate the number of moles ( or mass or number of particles) of another substance in the balanced equation.
4. define limiting and excess reactants.
5. identify the following types of reactions:

synthesis
decomposition
combustion
single-replacement
double-replacement
neutralization

6. define endothermic and exothermic reactions.
7. define acids and bases.

CHEMICAL REACTIONS
6.1 Law of conservation of energy
6.2 Chemical reactions: Law of conservation of mass
Reading: Hebden – page 105-106
6.3 Balancing chemical equations
Reading: Hebden – page 107-112
6.4 What is an aqueous solution? Dissolving NaCl (1st video) NaCl (s) Na⁺ (aq) + Cl^– (aq) Dissolving NaCl (2nd video) NaCl (s) Na⁺ (aq) + Cl^– (aq) Dissolving copper(II) chloride CuCl₂ (s) Cu⁺² (aq) + 2 Cl^– (aq)
6.5 Types of Reactions Five major classes of chemical reactions Combination or Synthesis reactions Decomposition Reactions Single-replacement reactions PREDICT by using the table of activity series of metals PREDICT single replacement reactions involving non-metals (halogens) Examples: Penny reactions \| Explanations using the activity series of metals Two single replacement reactions What happens when aluminum is dipped in a copper (II) chloride? What happens when magnesium is dipped in a copper (II) chloride? 2 Al (s) + 3 CuCl₂ (aq) 2 AlCl₃ (aq) + 3 Cu (s) Mg (s) + CuCl₂ (aq) MgCl₂ (aq) + Cu (s) Double-replacement reactions PREDICT by using the table of solubility rules of ionic compounds in water Two double replacement reactions What happens when potassium chromate is mixed with silver nitrate? What happens when potassium iodide is mixed with lead (II) iodide? K₂CrO₄ (aq) + 2 AgNO₃ (aq) Ag₂CrO₄ (s) + 2 KNO₃ (aq) 2 KI (aq) + Pb(NO₃)₂ (aq) PbI₂ (s) + 2 KNO₃ (aq) Neutralization reactions – a special class of double replacement reaction involving an acid and a base HCl (aq) + NaOH (aq) NaCl (aq) + H₂O (l) H₂SO₄ (aq) + 2 KOH (aq) K₂SO₄ (aq) +2 H₂O (l) Combustion reactions SUMMARY Demonstrations of the five major classes of chemical reactions Synthesis or Combination Cu (s) + S (g) CuS (s) Decomposition Ca(OH)₂ (s) CaO (s) + H₂O (g) Single Replacement 2 Al (s) + Fe₂O₃ (s) 2 Fe(s) + Al₂O₃ (s) Double Replacement KI (aq) + Hg₂(NO₃)₂ (aq) KNO₃ (aq) + HgI (s) Combustion CH₄ (g) + 2 O₂ (g) CO₂ (g) + 2 H₂O (l)
Reading: Hebden – page 114-118
6.6 Endothermic and exothermic reactions Bill Nye The Science Guy on Chemical Reactions
6.7 Acids and bases Strong and weak acids Strong and weak bases Titration
PROBLEMS: Balance chemical equations Classify and balance chemical equations Predict and balance chemical equations

CHEM 0011

Unit 6

Chemistry feed

In lecture, we talked about ..

CHEM 0011