I think the Ksp for Calcium Carbonate is around 5×10⁻⁹
(I don't know if this is the Ksp value that you use because I read somewhere that this value can vary. You should probably check with your teacher with what Ksp value they want you to use)
the equation for the dissociation CaCO₃ in water is CaCO₃(s)⇄Ca²⁺(aq)+CO₃²⁻(aq) which means that the concentration of Ca²⁺ is equal to the concentration of CO₃²⁻ in solution. For every molecule of CaCO₃ that dissolves, one atom of Ca²⁺ and one molecule of CO₃²⁻ is put into solution which is why the concentrations are equal in solution.
Since Ksp=[Ca²⁺][CO₃²⁻] and we know that [Ca²⁺]=[CO₃²⁻] we can rewrite the equation as Ksp=x² since if you say that [Ca²⁺]=[CO₃²⁻] when you multiply them together you get the concentration squared (I am calling the concentration x for right now).
when solving for x:
5×10⁻⁹=x²
x=0.0000707
Therefore [Ca²⁺]=[CO₃²⁻]=0.0000707mol/L which also shows how much calcium carbonate is dissolved per liter of water since the amount of Ca²⁺ and CO₃²⁻ in solution came from the calcium in a 1 to 1 molar ratio as shown in the equation (the value we found for x is the molar solubility of calcium carbonate).
Using the fact that the molar mass of calcium carbonate is 100.09g/mol you can use dimensional analysis as fallows:
(0.0000707mol/L)(100.09g/mol)=0.007077g/L
That means that there is 0.007077g of Calcium carbonate that can precipitate out of 1L of water.
since the question is asking for how much water needs to be evaporated to precipitate 100mg (0.1g) of Calcium you have to do the fallowing calculation:
(0.1g)/(0.007077g/L)=14.13L of water.
14.13L of water needs to evaporate in order to precipitate out 100mg of calcium carbonate
These types of questions can get long and confusing so I bolded parts that were important to try to guide you through it more easily.
I hope this helps. Let me know if anything is unclear.
Answer:
Lowering the temperature typically reduces the significance of the decrease in entropy. That makes the Gibbs Free energy of the reaction more negative. As a result, the reaction becomes more favorable overall.
Explanation:
In an addition reaction there's a decrease in the number of particles. Consider the hydrogenation of ethene as an example.
.
When 
is added to 
(ethene) under heat and with the presence of a catalyst, 
(ethane) would be produced.
Note that on the left-hand side of the equation, there are two gaseous molecules. However, on the right-hand side there's only one gaseous molecule. That's a significant decrease in entropy. In other words, 
.
The equation for the change in Gibbs Free Energy for a particular reaction is:
.
For a particular reaction, the more negative 
is, the more spontaneous ("favorable") the reaction would be.
Since typically for addition reactions, the "entropy term" of it would be positive. That's not very helpful if the reaction needs to be favorable.
(absolute temperature) is always nonnegative. However, lowering the temperature could help bring the value of
Actually, I strongly believe it is a switch.
The double replacement reaction
<h3>Further explanation</h3>
Given
Reaction if Na₂S + HCl
Required
Type of reaction
Solution
The double replacement reaction occurs when there is a displacement of the cations and anions of the reactants involved in the reaction to form two new compounds.
The general formula for this reaction :
AB + CD ⇒ AD + CB
At the bottom of the reaction, it is shown the number of atoms of each compound in the reactants and products which indicates the application of <em>the law of conservation of mass</em>, that the number of atoms in the reactants will be the same as the number of atoms in the product, so the reaction is said to be in a balanced state.
