Unit 3:Properties of Substances and Mixtures.

3.1 Intermolecular and Interparticle Forces.

List all intermolecular forces present in a pure sample.

  1. Identify all IMFs present in a pure sample of H₂O

Identify and label the presence of a hydrogen bond.

  1. Determine whether hydrogen bonding occurs in ammonia (NH3) and explain why.

Compare the strength of IMFs present in a sample.

  1. Rank London dispersion, dipole-dipole, and hydrogen bonding in order of strength.

Justify differences in physical properties of two substances based on IMF strength and atomic/electronic structure.

  1. Explain why H2O has a higher boiling point than H2S.

Use Lewis structures to determine IMFs and their impact on interactions.

  1. Draw the Lewis structure of CH2Cl2 and identify its intermolecular forces.

3.2 Properties of Solids.

Identify the type of solid given its formula or properties.

  1. Classify NaCl as ionic, molecular, metallic, or covalent network solid.
  2. A solid is is not conductive as a solide however creates a conductive solution when dissolved in water. What type of solid it is?

Use IMFs/interparticle forces to explain variations in physical properties.

  1. Explain why CH₄ is a gas at room temperature while C₆H₁₄ is a liquid.

Justify solid properties using representations of ionic, molecular, metallic, and network covalent solids.

  1. Explain why diamond (covalent network) is hard while NaCl (ionic) is brittle.

Compare and contrast the properties of different solid types.

  1. Compare the electrical conductivity of metallic solids vs. ionic solids.

3.3 Solids, Liquids, and Gases.

Compare the movement and packing of particles in different phases.

  1. Describe how particle arrangement differs between solids, liquids, and gases.

Draw a representation of a substance in solid, liquid, and gas phases.

  1. Sketch H2O molecules in solid, liquid, and gas states.

3.4 Ideal Gas Law.

Analyze graphs of P, V, T, and n to determine relationships.

  1. Sketch a graph of Pressure vs. Volume as a sample Argon (Ar) gas is compressed to a small volume wwith a piston at constant temperature.

Use PV = nRT to calculate gas conditions.

  1. Calculate the pressure of 2.0 mol of gas in a 5.0 L container at 300 K.

Determine unknown gas conditions given initial and final states.

  1. If a gas at 1.0 atm and 300 K is compressed to half its volume, what is the new pressure?

Apply mole fraction to determine partial pressure.

  1. A mixture contains 2 mol O₂ and 3 mol N₂ at 5 atm. What is the partial pressure of O₂?

Calculate gas density given identity, temperature, and pressure.

  1. Calculate the density of CO₂ at 1.00 atm and 298 K.

Convert between moles and volume of a gas at STP using the molar volume of a gas: 22.4L = 1 mol

  1. How many moles are in 224L of Ne(g) at 1 atm and 0oC?

3.5 Kinetic Molecular Theory.

Draw a representation of gases under given conditions.

  1. Sketch particle spacing for a gas at high vs. low pressure.
  2. The diagram below shows a particle diagram of a sample of O2(g) at 300K. Sketch the sample after it has been increase to 400K

    3. Particle diagram at 300K

Use the kinetic energy equation to compare gas velocities.

  1. Justify whether the average velocity of Neon (Ne) or Argon (Ar) is greater at 300K

Interpret Maxwell-Boltzmann distributions to identify unknown gases.

  1. The Maxwell-Boltzmann distribution of He at 300K is shown. Sketch the Maxwell-Boltzmann distribution of He at 400K.
    Maxwell-Boltzmann of He at 300K

3.6 Deviation from Ideal Gas Law.

Justify differences between ideal and real gas behavior based on gas properties, IMFs, and conditions.

  1. Explain why real gases deviate from ideal behavior at low temperature.

3.7 Solutions and Mixtures.

Use M = mol/L to calculate concentration, amount, mass, or volume.

  1. What is the concentration of a solution containing 0.50 mol NaCl in 250 mL?

Use M₁V₁ = M₂V₂ for dilution calculations.

  1. What volume of 2.0 M HCl is needed to make 500 mL of 0.50 M HCl?

3.8 Representations of Solutions.

Represent component interactions and concentrations using particulate models.

  1. Draw a particulate diagram showing Na+ and Cl- ions in aqueous solution.

Draw solutions with correct proportions to depict concentration.

  1. Sketch a solution with twice the concentration of solute compared to another.

Illustrate solute-solvent interactions.

  1. Draw how water molecules interact with Na+ ions in solution.

3.9 Separation of Solutions and Mixtures.

Choose the appropriate separation technique for a solution/mixture.

  1. How could a salt water solution be seperated into salt and water

Calculate Rf values from chromatography data.

  1. If a pigment moves 2.5 cm and the solvent front is 5.0 cm, calculate Rf.

Compare Rf values based on intermolecular interactions.

  1. Molecule A is more polar than Molecule B. Which molecule would travel further for a paper chromatography seperation using water as a solvent.

3.10 Solubility.

Determine miscibility of two liquids based on IMFs.s

  1. Explain why water and hexane are immiscible.

Select the best solvent for dissolving a solid solute based on IMFs

  1. Which solvent would best dissolve NaCl: hexane or water? Why?

3.11 Spectroscopy and the Electromagnetic Spectrum.

Assign the correct electromagnetic spectrum region for molecular rotation, vibration, and electronic energy transitions.

  1. Identify the region of the spectrum used to study molecular vibrations

3.12 Properties of Photons.

Convert between wavelength and frequency using c = λν.

  1. What is the frequency of light with a wavelength of 500 nm?

Convert between energy and frequency using E = hν.

  1. What is the energy of a photon with frequency 6.0 × 1014 Hz?

Use frequency as a bridge to convert between wavelength and energy.

  1. Determine the energy of a photon with wavelength 400 nm.

3.13 Beer-Lambert Law.

Select the correct wavelength for maximum absorbance based on absorbance vs. wavelength graphs.

  1. Use the absorption spectrum below to determine the wavelength a spectrophotometer should be set to determine the concentration of chlorophyll A.

    2. absorption spectrum of chlorophyll

Use absorbance vs. concentration graphs to find A or c.

  1. If ε = 1.2 L/mol·cm and b = 1.0 cm, what is A for a 0.20 M solution?

Recognize that the slope of A vs. c graphs equals εb.

  1. Given a slope of 0.80 in an A vs. c graph with b = 1.0 cm, calculate ε.

Use A = εbc to calculate concentration, given path length and molar absorptivity.

  1. A solution has A = 0.60, ε = 200 L/mol·cm, and b = 1.0 cm. What is its concentration?
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