Surface Chemistry Quiz

Surface Chemistry

• Surface chemistry is the study of reactions at interfaces.
• It's not just about reactions in bulk solutions, gases, or all phases.

Types of Adsorption

• Physical Adsorption: Adsorbate molecules held on the surface by van der Waals forces.
• Chemical Adsorption: Adsorbate molecules held by strong chemical bonds.
• Internal Adsorption: Adsorption within the pores of the material.
• Electrostatic Adsorption: Adsorption due to electrostatic forces.

Factors Affecting Adsorption

• Temperature: Higher temp generally decreases adsorption.
• Nature of adsorbent: Different materials adsorb different substances to varying degrees.
• Particle size of adsorbent: Smaller particles generally have higher surface area and thus greater adsorption.

Catalyst for Hydrogenation of Oils

• Nickel is commonly used as a catalyst in the hydrogenation of oils.

Chemisorption

• Chemisorption involves strong chemical bonds.
• Chemisorption is not reversible.
• Chemisorption is temperature dependent.

Langmuir Adsorption Isotherm

• Langmuir adsorption assumes adsorption at specific homogeneous sites, one molecule per site.
• Adsorption occurs in a single layer.
• Interactions between adsorbed molecules are negligible.

Studying Surface Area

• BET method is one method used to study the surface area.
• X-ray diffraction is used to study the crystal structure and bonding, which can help understand properties related to surface areas
• Mercury porosimetry is used, among other methods, to study porosity related to surface area.
• Gas adsorption is used in surface area studies

Stoichiometric Matrix (Example)

• The provided question refers to finding the correct stoichiometric matrix for a chemical reaction relating to the rate of the reaction, relating to each reaction

Reaction Rate

• Reaction rate is the change in concentration of a reactant or product with time.
• The rate law expresses the relationship of the reaction rate constant, and reactant concentrations.
• Different reaction orders relate to the underlying rate laws

Reaction Order

• The order of a reaction isn't always directly related to the stoichiometric coefficients.
• Elementary reactions follow this relationship(Reaction order is equivalent to stoichiometric coefficients).
• Other reaction types may deviate from this direct relationship

Activation Energy

• The minimum amount of energy required to initiate a reaction is activation energy.

Decomposition Reaction Orders

• If the half-life of a chemical reaction doubles each time, the reaction is a first-order reaction
• If the half-life stays the same regardless of the decomposition events, the reaction is a zero-order reaction

Proper Reactions

• For a reaction to occur, the reactants must have sufficient energy and proper orientation.

Reaction Intermediates

• Reaction intermediates are created during early steps of the reaction but consumed in later steps, useful for chemical reaction elucidation; they are temporary entities

Equilibrium Approximation

• Steady state approximation is used in rates of reactions when some conditions are equal to zero

Transport Processes

• Transport processes encompass the movement of substances or properties.
• Diffusion is one transport process and involves the movement of a substance from an area of higher concentration to an area of lower concentration.
• Conduction is a transport process, involving the movement of heat

Diffusion

• Diffusion is a common transport process that follows Fick's Law, which helps explain diffusion.