Chemistry Revision Booklet-Final T2 Exam

Part One: Nuclear Chemistry

Learning Objectives

• Describe key properties of alpha, beta, and gamma radiation

• Write and balance equations of nuclear reactions; recognize symbols for protons, neutrons, electrons, positrons, alpha particles, beta particles, and gamma rays

• Recognize a band of stability plot and predict decay type

• Calculate half-life, radiochemical dating, and remaining amounts of radioisotopes

• Deduce half-life from graphical representations

• Calculate nuclear binding energy in MEV

• Compare nuclear fission and fusion

• Differentiate nuclear reactions from chemical reactions

Properties of Radiation

Table 2: Alpha, Beta, and Gamma Radiation

• Alpha Radiation (Symbol: a)

  • Composition: Helium nuclei (He)

  • Charge: 2+

  • Mass: 6.64 × 10⁻²⁷ kg

  • Energy: ~5 MeV

  • Penetrating Power: Blocked by paper

• Beta Radiation (Symbol: β)

  • Composition: Electrons

  • Charge: 1-

  • Mass: 9.11 × 10⁻³¹ kg

  • Energy: 0.05 to 1 MeV

  • Penetrating Power: Blocked by metal foil

• Gamma Radiation (Symbol: Y)

  • Composition: Photons

  • Charge: 0

  • Mass: 0

  • Energy: ~1 MeV

  • Penetrating Power: Not completely blocked by lead or concrete

Nuclear Reactions and Equations

• In balanced nuclear equations, mass number and atomic number must equal on both sides.

• Example:

  • Alpha Radiation: 238U → 234Th + 4He

Radioactive Decay Processes

Types of Decay:

• Alpha Decay: Loss of He nucleus from heavy nuclei

• Beta Decay: Conversion of a neutron to a proton and emission of a beta particle

• Electron Capture: Nucleus captures an electron, converting a proton to a neutron

• Positron Emission: Conversion of a proton to a neutron with emission of a positron

Band of Stability

• Stability is determined by the neutron-to-proton ratio (N/Z).

• Points within the band of stability indicate stable nuclei; outside indicates instability and potential for different decay processes.

Radioactive Half-Life

• Half-life is the time required for half of a sample to decay.

• Calculation Example: A = A0 × (1/2)ⁿ where n = number of half-lives.

• Example for Radium-226 decay over 4800 years: 25 mg remaining after 3 half-lives.

Nuclear Binding Energy

• Binding energy relates to the difference between the mass of nucleons and the mass of the nucleus.

• Nuclear binding energy is the energy required to disassemble a nucleus into its constituent protons and neutrons.

Fission vs. Fusion

• Fission: Splitting of a large nucleus into lighter nuclei (e.g., U-235).

• Fusion: Combining of light nuclei into a heavier nucleus (e.g., hydrogen into helium in stars).

Nuclear vs Chemical Reactions

Comparison Table:

Part Two: Substituted Hydrocarbons

Learning Objectives

• Identify organic compounds by functional groups

• Name substituted hydrocarbons

• Classify reactions: substitution, addition, elimination, oxidation-reduction, condensation

• Identify compounds by physical properties

Organic Compounds Classification

Functional Groups:

• Halocarbon: R-X (Halogen)

• Alcohol: R-OH (Hydroxy)

• Ester: R-C-O-R

• Amine: R-NH2 (Amino)

• Aldehyde: O=C

• Carboxylic Acid: R-C(O)OH

Naming Substituted Hydrocarbons

• Halocarbon: Named as substituents (e.g., chloro-, bromo-)

• Alcohol: -ol suffix

• Aldehyde: -al suffix, Ketone: -one suffix, Carboxylic acids: -oic suffix

• Esters: Name alkyl group followed by carboxylic acid part’s name with "oate" suffix

Classifying Organic Reactions

Reaction Types:

• Substitution: One atom/group replaces another

• Addition: Atoms/groups added to unsaturated compounds

• Elimination: Two groups removed, resulting in double bonds

• Oxidation-Reduction: Involves electron loss/gain

• Condensation: Two molecules combine with the loss of a small molecule (e.g., water)

Physical Properties of Organic Compounds

Boiling Points and Solubility:

• Boiling point influenced by intermolecular forces (stronger forces = higher boiling points)

• Solubility influenced by functional groups (e.g. hydroxyl groups in alcohols increase solubility).
  ### Summary:

• Carboxylic acids have highest boiling points due to hydrogen bonding; lower for aldehydes and ketones.

• Amines are basic in water; alcohols and acids display acidic behavior.