Part A: For the following systems at equilibrium A : 2NOCl(g) ⇌ 2NO(g) + Cl2(g)
B : H2(g) + I2(g) ⇌ 2HI(g)
Classify these changes by their effect.

Leftward shift - system A decrease container size
No shift - system B increase container size and system B decrease container size
Rightward shift - system A increase container size

Part B: For the following systems at equilibrium
A: CaCO3(s) ⇌ CaO(s) + CO2(g) ΔH = +178 kJ/mol
B : PCl3(g) + Cl2(g) ⇌ PCl5(g) ΔH = -88 kJ/mol
Classify these changes by their effect.

Leftward shift - system C decrease temperature and system D increase temperature
No Shift - N/A
Rightward shift - system C increase temperature and system D decrease temperature

Both of them I was able to figure out, but I want to know how or why those are the solutions to the questions? I ask this because I answered some wrong, until I guessed it, and I got it right.

1.consider the following balanced equation and answer parts a through. show calculations for each part.  

3 ag(s) + 4 hno3(aq) → 3 agno3(aq) + no(g) + 2 h2o(l)  

a. calculate the number of moles of agno3 produced by the reaction of 3 moles of ag with excess hno3. if the number to the left of the compound represents the number of moles of the compound which are present, then 3 moles of ag react with 4 moles hno3 to produce 3 moles agno3 (aq).

so the answer to a would be 3 moles.

b. calculate the number of moles of agno3 produced by the reaction of 108 grams of ag with excess hno3.  

i'm not sure how to plug in the grams of silver into an equation using moles to find how many moles are produced.

c. calculate the number of grams of agno3 produced by the reaction of 108 grams of ag with excess hno3  

d. calculate the number of moles of no produced as a byproduct of the reaction of 108 grams of ag with excess hno3.  

e. calculate the number of grams of no produced as a byproduct starting with 108 grams of ag and excess hno3.  

explanation:

what is the question?