Modeling Energy & Combustion

If the chemical reaction AB + CD → AD + BC releases heat, what is true of the chemical potential energy of the reactants and products?

• The potential energy of the reactants is higher than the potential energy of the products.

• The potential energy of the reactants is lower than the potential energy of the products.

• The potential energy of the reactants is the same as the potential energy of the products.

• Neither the reactants nor the products have potential energy.

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

How do endothermic reactions impact the overall kinetic energy of the molecules? SELECT ALL THAT APPLY.

• Energy is absorbed during an endothermic reaction.

• Energy is released during an endothermic reaction.

• An endothermic reaction increases the temperature of the surroundings.

• An endothermic reaction reduces the temperature of the surrroundings.

Tags

NGSS.HS-PS1-4

Wood is made mostly of cellulose and has a chemical formula of C₆H₁₀O₅. The chemical equation for this combustion reaction is: C₆H₁₀O₅(s) + 6O₂(g) → 6CO₂(g) + 5H₂O(g) + energy What type of reaction occurred?

• Exothermic

• Endothermic

• Neutralization

• Non-energetic

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Choose the words to complete the sentences. As wood burns, it undergoes a __________ change. The __________ produced by this change are forms of energy.

• physical, carbon dioxide and water

• physical, heat and light

• chemical, carbon dioxide and water

• chemical, heat and light

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

NGSS.HS-PS3-4

Consider the scenario in which you are sitting by the campfire on a cold night. Which description best summarizes the heat transfer that occurs?

• The burning of the wood absorbs energy from its surroundings. Heat is transferred from your body to the campfire.

• The burning of the wood releases energy to its surroundings. Heat is transferred from the campfire to your body.

• The heat released by the campfire is balanced by the heat absorbed from its surroundings, so that the heat flow out of the system equals the heat flow into the system.

• Heat does not flow between the campfire and your body, as thermal equilibrium already has been achieved.

Tags

NGSS.HS-PS3-4