We subtract the enthalpies of the reactants from that of the products:

Since this is < 0, this is an exothermic reaction.
 
        
        
        
Answer:
A)
1. Reaction will shift rightwards towards the products.
2. It will turn green.
3. The solution will be cooler..
B) It will turn green.
Explanation:
Hello,
In this case, for the stated equilibrium:

In such a way, by thinking out the Le Chatelier's principle, we can answer to each question:
A)
1. If potassium bromide, which adds bromide ions, is added more reactant is being added to the solution, therefore, the reaction will shift rightwards towards the products.
2. The formation of the green complex is favored, therefore, it will turn green.
3. The solution will be cooler as heat is converted into "cold" in order to reestablish equilibrium.
B) In this case, as the heat is a reactant, if more heat is added, more products will be formed, which implies that it will turn green.
Regards.
 
        
             
        
        
        
Answer is: acid-base indicator or pH indicators.
Acid-base indicators are usually weak acids or bases and they are chemical<span> detectors for hydrogen or hydronium cations.</span>
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄). Phenolphthalein is <span>colorless in </span>acidic<span> solutions and pink in </span>basic<span> solutions.
Another example is m</span><span>ethyl orange. It is red colour in acidic solutions and yellow colour in basic solutions.</span>
        
             
        
        
        
Method:
1) Find the atomic number in a periodic table: the number of electrons equal the atomic number
2) Use Aufbau rule
Element     atomic number       electron configuration
<span>
P                15                            1s2 2s2 2p6 3s2 3p3
Ca              20                            </span><span><span>1s2 2s2 2p6 3s2 3p6 4s2
</span>Si                14</span><span>                            1s2 2s2 2p6 3s2 3p2
S                 16</span><span><span>                            1s2 2s2 2p6 3s2 3p4
</span>Ga               31.                   </span><span><span>        1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p</span>       </span>