Question

2. Calculate the volume of 15.0M ammonia (NH3) needed to prepare 1.50 grams of tetramminecopper (II) sulfate monohydrate [Cu(NH3)4]sO4 H2O according to the overall reaction on the first page of the lab. calaboorhance at 740 nm calculate the enerav of one photon

Answer 1

SOLUTION:

Given balanced reaction:

Cu(H20)41 S04.H2O + 4NH3 + Cu(NH3)41S04.H2O + 4H2O

From the above balanced chemical equation, we have, 4 moles of Ammonia (NH₃) produces 1 mol of tetramminecopper (II) sulfate monohydrate ([Cu(NH₃)₄]SO₄.H₂O).

Given mass of tetramminecopper (II) sulfate monohydrate, m = 1.5 g.

Molar mass of tetramminecopper (II) sulfate monohydrate:

M = 63.546 g/mol +4 x 17 g/mol + 96 g/mol +18 g/mol

:: Molar mass = 245.546 g/mol

Therefore, no.of moles of tetramminecopper (II) sulfate monohydrate:

m ..n = 1.5 g 245.546 g/mol M

..n=6.1088 x 10-3 mol

Hence, no.of moles of ammonia reacted is given by:

:in = 4 x n = 4 x 6.1088 x 10-3 mol

n = 0.02444 mol

Given that, Molarity of ammonia= 15 M

Therefore, Volume of ammonia is given by:

n' 15 M 0.02444 mol 15 M V =

:: V = 1.629 X 10-3L

We have, 1 L = 1000 mL.

V = 1.629 x 10-3 X 1000 mL

V = 1.629 mL