Question

student exploration: reaction energy
vocabulary: calorimeter, chemical bond, endothermic, enthalpy, exothermic, hesss law
prior knowledge questions (do these before using the gizmo.)

1. two magnets are stuck together. what might you have to do to get them to separate?

1. suppose you held two magnets a short distance apart, then let go. what would happen?

1. think about the magnets in terms of energy. in which case do you increase the potential

energy of the magnets? in which case do you increase the kinetic energy of the magnets?

gizmo warm - up
just like magnets, atoms of different elements are
attracted together to form chemical bonds. breaking
these bonds requires energy. when a new bond forms,
energy is released and temperatures rise. in the reaction
energy gizmo, you will explore how the energy of chemical
bonding relates to temperature changes that occur during
chemical reactions.
to begin, check that reaction 1 and forward are selected. in this reaction, hydrogen (h₂) and
oxygen (o₂) react to form water (h₂o). the reaction takes place inside a device called a
calorimeter. inside the calorimeter, a small chamber holds the reactants. the rest of the
calorimeter is filled with water.

1. click play (▶). what happens?

1. how does the temperature change?

Explanation:

Prior Knowledge Questions

1. Answer Explanation: To separate two stuck magnets, you need to apply a force that overcomes the magnetic attraction between them. This usually involves pulling them apart with enough strength.

• Answer: You would need to apply a force (pull them apart) to overcome the magnetic attraction holding them together.

1. Answer Explanation: Magnets have opposite poles that attract each other. If two magnets are held a short distance apart with opposite poles facing, they will be pulled together by the magnetic force when released.

• Answer: If the magnets have opposite poles facing, they will be pulled towards each other (attract) and move together. If like poles are facing, they will push apart (repel), but typically, if held close with opposite poles, they attract.

1. Answer Explanation: Potential energy is related to the position or configuration of objects. When you separate the magnets (pull them apart against the magnetic force), you are doing work on them, which increases their potential energy (similar to stretching a spring). Kinetic energy is related to motion. When the magnets are released and move towards each other (if attracting) or away (if repelling), their speed increases, so their kinetic energy increases.

• Answer: You increase the potential energy of the magnets when you pull them apart (against the magnetic attraction, doing work to change their position). You increase the kinetic energy of the magnets when you release them and they move towards or away from each other (their speed increases as they move due to the magnetic force).

Gizmo Warm - up Questions

1. Answer Explanation: The reaction is \(2H_2+O_2

ightarrow2H_2O\). This is a combustion reaction (and also a synthesis reaction) of hydrogen and oxygen to form water. When you click play, the reactants (hydrogen and oxygen molecules) will react to form water molecules. Visually, in the Gizmo, you would see the \(H_2\) and \(O_2\) molecules interacting and forming \(H_2O\) molecules.

• Answer: The hydrogen (\(H_2\)) and oxygen (\(O_2\)) molecules react to form water (\(H_2O\)) molecules. So you will see the reactant molecules ( \(H_2\) and \(O_2\)) being converted into product molecules (\(H_2O\)).

1. Answer Explanation: The reaction \(2H_2 + O_2

ightarrow2H_2O\) is an exothermic reaction, meaning it releases energy in the form of heat. In a calorimeter, the heat released by the reaction will be transferred to the water in the calorimeter, causing the temperature of the water (and thus the temperature inside the calorimeter) to increase.

• Answer: The temperature increases. This is because the reaction between hydrogen and oxygen to form water is exothermic, meaning it releases heat, which raises the temperature of the surroundings (including the water in the calorimeter).

Answer:

Prior Knowledge Questions

1. Answer Explanation: To separate two stuck magnets, you need to apply a force that overcomes the magnetic attraction between them. This usually involves pulling them apart with enough strength.

• Answer: You would need to apply a force (pull them apart) to overcome the magnetic attraction holding them together.

1. Answer Explanation: Magnets have opposite poles that attract each other. If two magnets are held a short distance apart with opposite poles facing, they will be pulled together by the magnetic force when released.

• Answer: If the magnets have opposite poles facing, they will be pulled towards each other (attract) and move together. If like poles are facing, they will push apart (repel), but typically, if held close with opposite poles, they attract.

1. Answer Explanation: Potential energy is related to the position or configuration of objects. When you separate the magnets (pull them apart against the magnetic force), you are doing work on them, which increases their potential energy (similar to stretching a spring). Kinetic energy is related to motion. When the magnets are released and move towards each other (if attracting) or away (if repelling), their speed increases, so their kinetic energy increases.

• Answer: You increase the potential energy of the magnets when you pull them apart (against the magnetic attraction, doing work to change their position). You increase the kinetic energy of the magnets when you release them and they move towards or away from each other (their speed increases as they move due to the magnetic force).

Gizmo Warm - up Questions

1. Answer Explanation: The reaction is \(2H_2+O_2

ightarrow2H_2O\). This is a combustion reaction (and also a synthesis reaction) of hydrogen and oxygen to form water. When you click play, the reactants (hydrogen and oxygen molecules) will react to form water molecules. Visually, in the Gizmo, you would see the \(H_2\) and \(O_2\) molecules interacting and forming \(H_2O\) molecules.

• Answer: The hydrogen (\(H_2\)) and oxygen (\(O_2\)) molecules react to form water (\(H_2O\)) molecules. So you will see the reactant molecules ( \(H_2\) and \(O_2\)) being converted into product molecules (\(H_2O\)).

1. Answer Explanation: The reaction \(2H_2 + O_2

ightarrow2H_2O\) is an exothermic reaction, meaning it releases energy in the form of heat. In a calorimeter, the heat released by the reaction will be transferred to the water in the calorimeter, causing the temperature of the water (and thus the temperature inside the calorimeter) to increase.

• Answer: The temperature increases. This is because the reaction between hydrogen and oxygen to form water is exothermic, meaning it releases heat, which raises the temperature of the surroundings (including the water in the calorimeter).