Equilibrium occurs when forward and reverse directions of a reversible reaction occur at the same rate so there is no overall change in the amounts of reactants and products.
Sorry this will probably be pretty long.
So think of the "control" as being something you yourself add to increase or decrease the effects in an experiment.
I'll give you an example so it is not as confusing.
Say you have decided to make an experiment on plants. Which plant can grow the fastest on which type of liquid? What is being added to this experiment? The liquid! Or all of the liquids you used. Like if you used Coke, Lime Gatorade, Orange Gatorade, and Water. Each drink will EFFECT each plant differently.
Hope I was of any hope?
D. photons it contains light but with zero mass
Answer:
4180J
Explanation:
(25.0g)(4.184J/g°C)(75°C-35.0°C)
(25.0g)(40.0°C)(4.184J/g°C)
(1.00*10³g°C)(4.184J/g°C) = 4184J
use sig figs:
4180J
