Answer:
The correct answer is: pH= 4.70
Explanation:
We use the <em>Henderson-Hasselbach equation</em> in order to calculate the pH of a buffer solution:
![pH= pKa + log   \frac{ [conjugate base]}{[acid]}](https://tex.z-dn.net/?f=pH%3D%20pKa%20%2B%20log%20%20%20%5Cfrac%7B%20%5Bconjugate%20base%5D%7D%7B%5Bacid%5D%7D)
Given:
pKa= 4.90
[conjugate base]= 4.75 mol
[acid]= 7.50 mol
We calculate pH as follows:
pH = 4.90 + log (4.75 mol/7.50 mol) = 4.90 + (-0.20) = 4.70
 
        
             
        
        
        
Answer:
B. CaCl + LiCO3 yields CaCO3 + LiCl is not correct 
It should be CaCl2 + Li2CO3  → 2LiCl + CaCO3
Explanation:
For a reaction to be double displacement reaction there are two things we need to look for
1) There must be an interchange of the group of ions
2) The reactants must dissolve in water to release ions
A. 2RbNO3 + BeF2 yields Be(NO3)2 + 2RbF
2Rb+ + NO3- + Be^2+ + 2F- → Be(NO₃)₂ + 2RbF
This is correct
B. CaCl + LiCO3 yields CaCO3 + LiCl
This is not correct
The correct equation is:
CaCl2 + Li2CO3  → Ca2+ + 2Cl- + 2Li+ + CO3^2-  → 2LiCl + CaCO3
C. Na3PO4 + 3KOH yields 3NaOH + K3PO4
3Na+ + PO4^3- + 3K+ + 3OH- → 3NaOH + K3PO4
This is correct
D. 2MgI2 + Mn(SO3)2 yields 2MgSO3 + MnI4
 2Mg^2+ + 4I- + Mn^4+ + 2SO3^2- → 2 MgSO3 + MnI4
This is correct
 
        
             
        
        
        
Answer:
Mg(OH)2 + 2HCI ⇒ MgCI2 + 2H2O
Explanation:
In order to balance a chemical equation you need to make sure both sides of the equations are equal.
Mg(OH)2 + 2HCI = MgCI2 + H2O
Mg = 1
Oh = 2
HCI = 2
Products:
Mg = 1
CI = 2
H = 2
O = 1
2H20 = 1 × 2 = 2
2 × 2 = 4
2HCI 
1 × 2 = 2
Mg(OH)2 + 2HCI ⇒ MgCI2 + 2H2O
Hope this helps.
 
        
             
        
        
        
D.) "Vaporization" <span>is not a form of heat transfer.
It is just conversion of the state of matter from Liquid to Vapor
Hope this helps!</span>