Name: ______________________________________ Date: ________________________
Student Exploration: Equilibrium and Concentration
Vocabulary: chemical equilibrium, concentration, equilibrium, equilibrium constant, reaction
quotient, reversible reaction
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Gary has $5,000 in his bank account and earns a modest salary. Every month he pays for rent,
food, utilities, and entertainment.
A. How will Gary’s account change if he saves more than he spends? It will
increase.
B. How will Gary’s account change if he spends more than he saves? It will
increase.
C. What happens if Gary spends exactly as much as he saves? It will stay the
same.
Gizmo Warm-up
If Gary spends exactly as much as he earns, his savings will
be in equilibrium. Equilibrium occurs when two opposing
processes occur at the same rate, leading to no net change.
In the Equilibrium and Concentration Gizmo, you will
investigate how equilibrium can occur in chemical reactions.
To begin, check that Reaction 1 is selected. Set Moles NO2
to 8 and Moles N2O4 to 0.
1. Click Play ( The NO2
) and observe the colliding molecules. What do you notice?
molecules are free floating closer to the surface of the fluid in
the beaker. The NO2 molecules start to bond forming N2O4
molecules. After a while, the N2O4 molecules start to break
apart again into NO2 molecules. The fluid they reaction is
occurring in is also decreasing and rising intermediately but
leaning more to decreasing than increasing.
In the Gizmo, a blue flash appears every time two reactants combine to form a product. A
red flash appears every time a product dissociates into reactants.
2. Click Reset ( ), and set Moles NO2 to 0 and Moles N2O4 to 8. Click Play.
, All of N2O4 molecules are on the bottom of
What do you notice now?
the beaker. As the N2O4 bonds are broken into NO2 molecules.
After a while, the NO2 molecules start to reform N2O4 molecules
and the number of N2O4 molecules rise again. After a while it
repeats the cycle. The fluid rises and decreases intermediately
as the bonds break and form. Leaning more to the increasing
than decreasing.
3. When a reaction can proceed in either direction, it is a reversible reaction. Based on what
you have observed, is the synthesis of NO2 into N2O4 a reversible reaction? Explain. Yes,
because in both directions the bonds are formed and/or broken
then reformed. One direction decreases more, and the other
direction increases more. I think the rate of change in either
direction is equal.
2019
Student Exploration: Equilibrium and Concentration
Vocabulary: chemical equilibrium, concentration, equilibrium, equilibrium constant, reaction
quotient, reversible reaction
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Gary has $5,000 in his bank account and earns a modest salary. Every month he pays for rent,
food, utilities, and entertainment.
A. How will Gary’s account change if he saves more than he spends? It will
increase.
B. How will Gary’s account change if he spends more than he saves? It will
increase.
C. What happens if Gary spends exactly as much as he saves? It will stay the
same.
Gizmo Warm-up
If Gary spends exactly as much as he earns, his savings will
be in equilibrium. Equilibrium occurs when two opposing
processes occur at the same rate, leading to no net change.
In the Equilibrium and Concentration Gizmo, you will
investigate how equilibrium can occur in chemical reactions.
To begin, check that Reaction 1 is selected. Set Moles NO2
to 8 and Moles N2O4 to 0.
1. Click Play ( The NO2
) and observe the colliding molecules. What do you notice?
molecules are free floating closer to the surface of the fluid in
the beaker. The NO2 molecules start to bond forming N2O4
molecules. After a while, the N2O4 molecules start to break
apart again into NO2 molecules. The fluid they reaction is
occurring in is also decreasing and rising intermediately but
leaning more to decreasing than increasing.
In the Gizmo, a blue flash appears every time two reactants combine to form a product. A
red flash appears every time a product dissociates into reactants.
2. Click Reset ( ), and set Moles NO2 to 0 and Moles N2O4 to 8. Click Play.
, All of N2O4 molecules are on the bottom of
What do you notice now?
the beaker. As the N2O4 bonds are broken into NO2 molecules.
After a while, the NO2 molecules start to reform N2O4 molecules
and the number of N2O4 molecules rise again. After a while it
repeats the cycle. The fluid rises and decreases intermediately
as the bonds break and form. Leaning more to the increasing
than decreasing.
3. When a reaction can proceed in either direction, it is a reversible reaction. Based on what
you have observed, is the synthesis of NO2 into N2O4 a reversible reaction? Explain. Yes,
because in both directions the bonds are formed and/or broken
then reformed. One direction decreases more, and the other
direction increases more. I think the rate of change in either
direction is equal.
2019
