Am I doing this right?
What is [OH-] of a solution
with a pH of 4.0?
Answer in M
Ya
I believe it is A because 32C would be way too much and it wouldnt go down to -5
Answer:
Option A - When |ΔHsolute| > |ΔHhydration|
Explanation:
A solution is defined as a homogeneous mixture of 2 or more substances that can either be in the gas phase, liquid phase, solid phase.
The enthalpy of solution can either be positive (endothermic) or negative (exothermic).
Now, we know that enthalpy is amount of heat released or absorbed during the dissolving process at constant pressure.
Now, the first step in thus process involves breaking up of the solute. This involves breaking up all the intermolecular forces holding the solute together. This means that the solute molecules are separate from each other and the process is always endothermic because it requires energy to break interaction. Thus;
The enthalpy ΔH1 > 0.
Thus, the enthalpy of the solute has to be greater than the enthalpy of hydration.
When the solute can no longer dissolve in the solution the solvent becomes SATURATED. When no more solute can dissolve and if you look at the bottom of the beaker, test tube, pan, or glass of cold tea you can see the solute permeating out as little particles .
Answer:
8.61 mL of the HCl solution
Explanation:
The reaction that takes place is:
- 2HCl + Mg(OH)₂ → MgCl₂ + 2H₂O
From the given mass of Mg(OH)₂, we can calculate <u>the moles of HCl that are neutralized</u>:
- 4x10² mg = 400 mg = 0.400g
- 0.400g Mg(OH)₂ ÷ 58.32g/1mol = 6.859*10⁻³ mol Mg(OH)₂
- 6.859*10⁻³ mol Mg(OH)₂ *
3.429x10⁻³ mol HCl
Finally, to calculate the volume of an HCl solution, we need both the moles and the concentration. We can <u>calculate the concentration using the pH value</u>:
= [H⁺]
- 0.0398 M = [H⁺] = [HCl] *Because HCl is a strong acid*
Thus, the volume is:
- 0.0398 M = 3.429x10⁻³mol HCl / Volume
- Volume = 8.616x10⁻³ L = 8.62 mL
