Calculate %NH3 in Complex by Titration: How-To Guide

[kaitoufion]

Percentage of NH3?

Recently I've done an experiment and we are required to determine the percentage NH3 in the complex by mass.

I had no problem doing the experiment but stuck in the calculation part

Really hope someone can help me here! >.<

The experiment was done by titration, the complex we used is... (CuSO4*5H2O + H2O + NH3 + ethanol + acetone) - sorry I don't know how I should call this @.@ But those are the things we used to make that complex...

First I dissolved 0.2g of the complex with 25mL H2O, & 31.05mL of standardized 0.1M HCl was used to titrate it. Then we are required to find "%NH3"...

Can someone please kindly tell me (at least the formula that I need to use) to calculate the percentage NH3? :'(

Thanks so much! :shy:

 

[Gokul43201]

My best guess is that your complex is tetrammine copper(II) sulfate - [Cu(NH₃)₄]SO₄.H₂O

Was it deep blue in color? Did you have to make the crystals by evaporation?

 

[Blueshift5]

I can provide a step-by-step guide to help you calculate the percentage of NH3 in your complex using titration data. First, you will need to determine the moles of HCl used in the titration. This can be calculated by multiplying the volume of HCl used (in liters) by the molarity of the HCl solution. In this case, the moles of HCl used would be (31.05 mL/1000 mL) x (0.1 moles/L) = 0.003105 moles HCl.

Next, you will need to determine the moles of NH3 in the complex. This can be done by using the balanced equation for the reaction between NH3 and HCl. In this case, the equation would be:

NH3 + HCl --> NH4Cl

From this equation, we can see that 1 mole of NH3 reacts with 1 mole of HCl. Since we know the moles of HCl used in the titration, we can assume that the same number of moles of NH3 were present in the complex. Therefore, the moles of NH3 in the complex would also be 0.003105 moles.

Now, we can use the mass of the complex (0.2g) and the moles of NH3 (0.003105 moles) to calculate the percentage of NH3 in the complex. This can be done using the following formula:

%NH3 = (mass of NH3/mass of complex) x 100%

In this case, the mass of NH3 would be the molar mass of NH3 (17.03 g/mol) multiplied by the moles of NH3 (0.003105 moles). The mass of the complex would be 0.2g. Plugging in these values, we get:

%NH3 = (17.03 g/mol x 0.003105 moles)/0.2g x 100% = 0.5265%

Therefore, the percentage of NH3 in the complex is 0.5265%. I hope this helps you with your calculations. If you have any further questions, please don't hesitate to ask.