This demonstration is most likely trying to show you potential energy. The rock is heavier than the pebble and will therefore displace more sand upon impact showing that the rock stores more potential energy than the pebble does when they are elevated to the same height (in this case the height is the height of the table).
This makes sense since potential energy is equal to mass times the acceleration due to gravity times height (PE=mgh) and the only thing that is changing is the mass of the object being suspended which means that the heavier object (the rock) will have more potential energy.
I hope this helps. Let me know if anything is unclear.
For the reaction below at dynamic equilibrium, it is true that the rate of the forward reaction equals the rate of the reverse reaction.
Let's consider the following reaction at equilibrium.
N₂(g) + 3 H₂(g) = 2 NH₃(g)
<h3>What is the chemical equilibrium?</h3>
Is a state in which the concentrations of reactants and products are constant and the forward reaction rate and constant reaction rate are equal.
<h3>What is the equilibrium constant?</h3>
The equilibrium constant (K) is the ratio of the concentrations of the products to the concentrations of the reactants, all raised to their stoichiometric coefficients.
Let's consider which statement is true for the equilibrium system.
- The concentration of NH₃ is greater than the concentration of N₂. FALSE. There is not enough information to confirm this, we would need to know the value of K.
- The concentration of NH₃ equals the concentration of N₂. FALSE. There is not enough information to confirm this, we would need to know the value of K.
- The rate of the forward reaction equals the rate of the reverse reaction. TRUE. This is always true for a reaction at equilibrium.
- The rate of the forward reaction is greater than the rate of the reverse reaction. FALSE. At equilibrium, both rates are equal.
For the reaction below at dynamic equilibrium, it is true that the rate of the forward reaction equals the rate of the reverse reaction.
Learn more about chemical equilibrium here: brainly.com/question/5081082
Answer:

Explanation:
N2(g)+O2(g)⇌2NO(g), 
N2(g)+2H2(g)⇌N2H4(g), 
2H2O(g)⇌2H2(g)+O2(g), 
If we add above reaction we will get:
2N2(g)+2H2O(g)⇌2NO(g)+N2H4(g) Eq (1)
Equilibrium constant for Eq (1) is 
Divide Eq (1) by 2, it will become:
N2(g)+H2O(g)⇌NO(g)+1/2N2H4(g) Eq (2)
Equilibrium constant for Eq (2) is 

Answer:
If a pregnant woman eats 6.00 oz servings of bluefish in a month, she would be consuming 1.926 x 10⁻⁶ oz of mercury.
Explanation:
0.321 oz mercury __________________ 1 x 10⁶ oz fish
x __________________ 6.00 oz fish
x = 1.926 x 10⁻⁶ oz mercury