Chemical Reactions and Energy Changes

The video tutorial explains thermochemical equations, which are balanced chemical reactions that include an energy term. It covers photosynthesis as an endothermic reaction where energy is stored, and cellular respiration as an exothermic reaction where energy is released. The tutorial discusses the specificity of energy terms to reaction coefficients and demonstrates how changing these coefficients affects the energy required or released. Examples include the combustion of methane and ethane, illustrating how to calculate energy changes when reaction coefficients are adjusted.

What is a thermochemical equation?

• A reaction that occurs only at high temperatures.

• A balanced chemical reaction with an energy term.

• A chemical reaction that includes a catalyst.

• A chemical equation that involves only gases.

In the photosynthesis equation, where is the energy term located?

• On the reactant side.

• On both sides of the equation.

• On the product side.

• There is no energy term.

What type of reaction is photosynthesis?

• Exothermic

• Neutral

• Endothermic

• Spontaneous

How does cellular respiration differ from photosynthesis in terms of energy?

• It absorbs energy.

• It stores energy.

• It releases energy.

• It requires no energy.

What happens to the energy term when the coefficients in a reaction are doubled?

• The energy term is halved.

• The energy term is tripled.

• The energy term remains the same.

• The energy term is doubled.

If you produce two moles of glucose, how many moles of CO2 are needed?

• 6 moles

• 12 moles

• 18 moles

• 24 moles

What is the energy change when three moles of methane are combusted?

• 3200 kJ

• 2407.5 kJ

• 1605 kJ

• 802.5 kJ

How many moles of oxygen are required for the combustion of three moles of methane?

• 3 moles

• 12 moles

• 9 moles

• 6 moles

In the combustion of ethane, how many moles of water are produced from two moles of ethane?

• 6 moles

• 9 moles

• 12 moles

• 3 moles

What is the energy change for the production of 12 moles of water in the combustion of ethane?

• 11427.2 kJ

• 8570.4 kJ

• 5713.6 kJ

• 2856.8 kJ