CPT Chemical Process Fundamentals & Reactions 2 — Questions and Answers
Question 1: What is stoichiometry used for in chemical process operations?
- Determining the physical properties of process streams
- Calculating the quantitative relationships between reactants and products (Correct answer)
- Measuring the viscosity of process fluids
- Selecting the correct valve type for a given pressure drop
Correct answer: Calculating the quantitative relationships between reactants and products
Stoichiometry uses balanced chemical equations to calculate the exact amounts of reactants needed and products formed in a chemical reaction.
Question 2: What is activation energy in the context of chemical reactions?
- The total energy released when products form
- The minimum energy required for reactants to form products (Correct answer)
- The heat content of the product molecules
- The energy stored in chemical bonds of the reactants
Correct answer: The minimum energy required for reactants to form products
Activation energy is the minimum energy that reactant molecules must have for a collision to result in a chemical reaction.
Question 3: In a neutralization reaction between a strong acid and a strong base, what are the typical products?
- An oxide and hydrogen gas
- A salt and water (Correct answer)
- Carbon dioxide and water vapor
- An ester and an alcohol
Correct answer: A salt and water
A neutralization reaction between an acid (H⁺ donor) and a base (OH⁻ donor) produces a salt and water.
Question 4: In terms of electron transfer, what is oxidation?
- Gain of electrons by a species
- Loss of electrons by a species (Correct answer)
- Transfer of protons from one atom to another
- Formation of a covalent bond between two atoms
Correct answer: Loss of electrons by a species
Oxidation is defined as the loss of electrons by a substance; the mnemonic OIL RIG (Oxidation Is Loss, Reduction Is Gain) helps remember this.
Question 5: What does the equilibrium constant (Keq) indicate about a chemical reaction?
- The speed at which equilibrium is reached
- The ratio of product concentrations to reactant concentrations at equilibrium (Correct answer)
- The activation energy of the forward reaction
- The amount of catalyst required to drive the reaction
Correct answer: The ratio of product concentrations to reactant concentrations at equilibrium
Keq is the ratio of product concentrations to reactant concentrations (each raised to their stoichiometric coefficients) at equilibrium, indicating the extent of reaction.
Question 6: What is the mole concept, and why is it important in chemical process calculations?
- A unit of temperature used in thermodynamic calculations
- A counting unit representing 6.022 × 10²³ particles, enabling mass-to-particle conversions (Correct answer)
- A measure of the viscosity of process fluids at standard conditions
- A ratio used to determine the flow rate of gases in pipelines
Correct answer: A counting unit representing 6.022 × 10²³ particles, enabling mass-to-particle conversions
The mole (Avogadro's number = 6.022 × 10²³) allows technicians to relate macroscopic masses to numbers of atoms or molecules for reaction calculations.
Question 7: Which of the following correctly describes an endothermic chemical reaction?
- Releases heat; products are at lower energy than reactants
- Absorbs heat from surroundings; products are at higher energy than reactants (Correct answer)
- Occurs spontaneously at all temperatures without energy input
- Produces an electrical current as a by-product
Correct answer: Absorbs heat from surroundings; products are at higher energy than reactants
An endothermic reaction absorbs heat from the surroundings (ΔH > 0), meaning the products have more enthalpy than the reactants.
CPT Chemical Process Fundamentals & Reactions 2
What is stoichiometry used for in chemical process operations?