Question 1: Define an exothermic reaction and explain its significance in the context of rocket fuel combustion.

Answer: An exothermic reaction releases energy in the form of heat, which is crucial for providing the thrust needed to propel rockets in space missions.

Question 2: Describe what a reaction profile illustrates about the energy changes during a chemical reaction.

Answer: A reaction profile shows the energy changes from reactants to products, including the activation energy and whether the reaction is exothermic or endothermic.

Question 3: In the context of space exploration, why is understanding activation energy important when designing rocket propellants?

Answer: Understanding activation energy helps in designing propellants that ignite reliably under specific conditions, ensuring safety and efficiency during launch.

Question 4: Calculate the energy change (ΔE) for a reaction where the activation energy is 150 kJ/mol and the energy barrier to the reaction is 50 kJ/mol.

Answer: ΔE = Activation energy - Energy barrier = 150 kJ/mol - 50 kJ/mol = 100 kJ/mol

Question 5: Identify which of the following is an endothermic process relevant to space technology: A) Combustion of hydrogen B) Absorption of heat by a spacecraft's thermal shield C) Charging of a spacecraft's batteries D) Detonation of rocket fuel

Answer: B) Absorption of heat by a spacecraft's thermal shield

Question 6: Fill in the blank: An endothermic reaction absorbs energy, which is represented on a reaction profile as a _______ in energy from reactants to products.

Answer: rise

Question 7: Explain how reaction profiles can help scientists determine the safety of a rocket fuel mixture.

Answer: Reaction profiles enable scientists to understand the activation energy and energy release of fuel reactions. High activation energies indicate more stable fuels, reducing the risk of accidental ignition, while the energy change indicates the amount of heat released, which must be controlled for safety in space missions.

Question 1: A certain rocket fuel releases 2500 kJ of energy when combusted. If the molar amount of fuel used is 5 mol, what is the energy change per mole? Show your working.

Answer: Energy change per mole = Total energy / Number of moles = 2500 kJ / 5 mol = 500 kJ/mol

Question 2: Design a simple experiment (theory only) to measure the energy change of a chemical reaction used in spacecraft thermal regulation. Include variables and safety precautions.

Answer: Students could set up a calorimeter with known quantities of reactants to measure temperature change during the reaction. Variables include reactant amounts, temperature, and pressure. Safety precautions involve handling chemicals with appropriate PPE, working in a well-ventilated area, and ensuring proper disposal of reactive substances.

Question 1: A spacecraft's thruster uses a fuel with an endothermic reaction profile. Discuss the challenges this presents for space propulsion and how engineers might overcome them.

Answer: Endothermic reactions absorb heat, which can reduce the overall energy output of the thruster. Engineers might overcome this by pre-heating the fuel, using catalysts to lower activation energy, or combining endothermic reactions with exothermic ones to ensure sufficient thrust is generated efficiently.

Question 2: Explain why reaction profiles are essential in developing safe and reliable rocket propellants for space missions.

Answer: Reaction profiles help identify energy release and activation energies, allowing chemists to assess stability, ignition temperature, and energy output, which are vital for ensuring safety and reliability of rocket propellants.