Exploring Thermochemistry Concepts

What is released when methane reacts with oxygen?

• Carbon dioxide and water

• Carbon monoxide

• Hydrogen gas

• Nitrogen

What is required to break chemical bonds?

• Light

• Heat

• Energy

• Water

What does Delta H represent?

• The energy change in a reaction

• The sound produced in a reaction

• The time taken for a reaction

• The color change in a reaction

What is the Delta H value for the combustion of methane?

• -890.4 kJ/mol

• 46 kJ/mol

• 890.4 kJ/mol

• -46 kJ/mol

What type of reaction is the combustion of methane?

• Exothermic

• Endothermic

• Photochemical

• Electrochemical

What is the Delta H value for the decomposition of ammonia?

• +46 kJ/mol

• -890.4 kJ/mol

• +890.4 kJ/mol

• -46 kJ/mol

Why do methane and oxygen not spontaneously react at room temperature?

• Insufficient methane

• Presence of inhibitors

• Lack of activation energy

• Excess oxygen

What is needed for methane and oxygen to react at room temperature?

• A decrease in pressure

• A catalyst

• An increase in temperature

• An initial energy source

What can initiate the reaction between methane and oxygen?

• Stirring

• Sunlight

• Freezing

• A spark or flame

What happens after the initial activation energy is provided in a methane combustion reaction?

• The reaction stops

• A chain reaction starts

• The reaction reverses

• The system cools down