<span>magnesium cations (Mg </span><span>2+</span>) and oxide anions (<span>O 2</span>−<span>)</span>
A chemical change changes the bonds by forming or breaking them, and cannot be brought back to it's original form.
b. milk souring
Answer:
The concentrations are :
![[HAsc^-]=0.000702 M](https://tex.z-dn.net/?f=%5BHAsc%5E-%5D%3D0.000702%20M)
![[Asc^{2-}]=5.92\times 10^{-8} M](https://tex.z-dn.net/?f=%5BAsc%5E%7B2-%7D%5D%3D5.92%5Ctimes%2010%5E%7B-8%7D%20M)
The pH of the solution is 3.15.
Explanation:

Initial
c 0 0
Equilibrium
c-x x x
![K_{a1}=\frac{[HAs^-][H^+]}{[H_2Asc]}](https://tex.z-dn.net/?f=K_%7Ba1%7D%3D%5Cfrac%7B%5BHAs%5E-%5D%5BH%5E%2B%5D%7D%7B%5BH_2Asc%5D%7D)


Solving for x:
x = 0.000702 M
![[HAsc^-]=0.000702 M](https://tex.z-dn.net/?f=%5BHAsc%5E-%5D%3D0.000702%20M)

Initially
x 0 0
At equilibrium ;
(x - y) y y
![K_{a2}=\frac{[As^{2-}][H^+]}{[HAsc^-]}](https://tex.z-dn.net/?f=K_%7Ba2%7D%3D%5Cfrac%7B%5BAs%5E%7B2-%7D%5D%5BH%5E%2B%5D%7D%7B%5BHAsc%5E-%5D%7D)


Putting value of x = 0.000702 M


![[Asc^{2-}]=5.92\times 10^{-8} M](https://tex.z-dn.net/?f=%5BAsc%5E%7B2-%7D%5D%3D5.92%5Ctimes%2010%5E%7B-8%7D%20M)
Total concentration of ![[H^+]=x+y=0.000702 M+5.92\times 10^{-8} M=7.0206\times 10^{-4} M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3Dx%2By%3D0.000702%20M%2B5.92%5Ctimes%2010%5E%7B-8%7D%20M%3D7.0206%5Ctimes%2010%5E%7B-4%7D%20M)
The pH of the solution :
![pH=-\log[H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BH%5E%2B%5D)

The quantity of heat absorbed is 33.4 kJ.
Δ<em>H</em>_fus = 334 J·g⁻¹
<em>q = m</em>Δ<em>H</em>_fus = 100.0 g × 334 J·g⁻¹ = 3.34 × 10⁴ J = 33.4 kJ
A solution must have both a solute and a solvent, and they must exist in solution together. the solute must be dissolved in the solvent; salt does not dissolve in a sugar bowl, nor does oil dissolve in water; it is a non polar molecule. we know that sugar (the solute) when added to water(solvent) will dissolve, creating a solution.
therefore, B