Answer:
Reversible reactions exhibit the same reaction rate for forward and reverse reactions at equilibrium.
Reversible reactions exhibit constant concentrations of reactants and products at equilibrium
Explanation:
A reversible reaction is a reaction that can proceed in both forward and backward direction.
Equilibrium is attained in a chemical system when there is no observable change in the properties of the system.
At equilibrium, a reversible reaction is occurring in at same rate. That is, the forward and backward reaction is occurring at the same rate. As the rate of the forward and backward reaction remains the same, the concentrations of the reactants and products will also be the same in order for the equilibrium to be maintained.
It's simple, just follow my steps.
1º - in 1 L we have

of

2º - let's find the number of moles.



3º - The concentration will be

But we have this reaction

This concentration will be the concentration of

![K_{sp}=\frac{[Ba^{2+}][CO_3^{2-}]}{[BaCO_3]}](https://tex.z-dn.net/?f=K_%7Bsp%7D%3D%5Cfrac%7B%5BBa%5E%7B2%2B%7D%5D%5BCO_3%5E%7B2-%7D%5D%7D%7B%5BBaCO_3%5D%7D)
considering
![[BaCO_3]=1~mol/L](https://tex.z-dn.net/?f=%5BBaCO_3%5D%3D1~mol%2FL)
![K_{sp}=[Ba^{2+}][CO_3^{2-}]](https://tex.z-dn.net/?f=K_%7Bsp%7D%3D%5BBa%5E%7B2%2B%7D%5D%5BCO_3%5E%7B2-%7D%5D)
and
![[Ba^{2+}]=[CO_3^{2-}]=5.07\times10^{-5}~mol/L](https://tex.z-dn.net/?f=%5BBa%5E%7B2%2B%7D%5D%3D%5BCO_3%5E%7B2-%7D%5D%3D5.07%5Ctimes10%5E%7B-5%7D~mol%2FL)
We can replace it


Therefore the

is:
Answer:
25,050 calories.
Explanation:
A calorie is the amount of energy needed to raise the temperature of one gram of water 1 degree centigrade. If we are raising 835 grams of water 30 degrees then we multiply 835*30 to get 25,050 calories.
D because that’s the only one that makes sense