Answer:
M
Explanation:
Concentration of
= 0.020 M
Constructing an ICE table;we have:
![Cu^{2+}+4NH_3_{aq} \rightleftharpoons [Cu(NH_3)_4]^{2+}_{(aq)}](https://tex.z-dn.net/?f=Cu%5E%7B2%2B%7D%2B4NH_3_%7Baq%7D%20%5Crightleftharpoons%20%5BCu%28NH_3%29_4%5D%5E%7B2%2B%7D_%7B%28aq%29%7D)
Initial (M) 0.020 0.40 0
Change (M) - x - 4 x x
Equilibrium (M) 0.020 -x 0.40 - 4 x x
Given that: 
![K_f } = \frac{[Cu(NH_3)_4]^{2+}}{[Cu^{2+}][NH_3]^4}](https://tex.z-dn.net/?f=K_f%20%7D%20%3D%20%5Cfrac%7B%5BCu%28NH_3%29_4%5D%5E%7B2%2B%7D%7D%7B%5BCu%5E%7B2%2B%7D%5D%5BNH_3%5D%5E4%7D)

Since x is so small; 0.40 -4x = 0.40
Then:








M
Answer:
In full volume it contain 0.12 moles.
Explanation:
Given data:
Total volume= Vt = 2.9 L
Decreased volume= Vd = 1.2 L
Number of moles of air present in decreased volume= n = 0.049 mol
Number of moles of air in total volume= n = ?
Solution:
Formula:
Vt/ Vd = n (in total volume) /n ( decreased volume)
2.9 L / 1.2 L = X / 0.049 mol
2.42 = X / 0.049 mol
X = 2.42 × 0.049
X = 0.12 mol
Molar mass of A l 2 (S O 4 ) 3 = 342.15 g/mol
7.2g/ 342.15 g/mol
you can get number of moles.
then multiply that by12