A florist prepares a solution of nitrogen-phosphorus fertilizer by dissolving 5.66 g of NH4NO3 and 4.42 g of (NH4)3PO4 in enough water to make 22.0 L solution. What is the molarity of NH4+ in the solution?

Respuesta :

Answer:

0.00725 M

Explanation:

Considering for [tex]NH_4NO_3[/tex]

Mass = 5.66 g

Molar mass of [tex]NH_4NO_3[/tex] = 80.043 g/mol

Moles = Mass taken / Molar mass

So,  

Moles = 5.66 / 80.043 moles = 0.0707 moles

[tex]NH_4NO_3[/tex] will dissociate as:

[tex]NH_4NO_3\rightarrow NH_4^++NO_3^-[/tex]

Thus 1 mole of [tex]NH_4NO_3[/tex] yields 1 mole of ammonium ions. So,

Ammonium ions furnished by [tex]NH_4NO_3[/tex] = 1 × 0.0707 moles = 0.0707 moles

Considering for [tex](NH_4)_3PO_4[/tex]

Mass = 4.42 g

Molar mass of [tex](NH_4)_3PO_4[/tex] = 149.09 g/mol

Moles = Mass taken / Molar mass

So,  

Moles = 4.42 / 149.09 moles = 0.0296 moles

[tex](NH_4)_3PO_4[/tex] will dissociate as:

[tex](NH_4)_3PO_4\rightarrow 3NH_4^++PO_4^{3-}[/tex]

Thus 1 mole of [tex]NH_4NO_3[/tex] yields 3 moles of ammonium ions. So,

Ammonium ions furnished by [tex](NH_4)_3PO_4[/tex] = 3 × 0.0296 moles = 0.0888 moles

Total moles of the ammonium ions = 0.0707 + 0.0888 moles = 0.1595 moles

Given that:

Volume = 22.0 L

So, Molarity of the [tex]NH_4^+[/tex] is:

Molarity = Moles / Volume = 0.1595 / 22 M = 0.00725 M

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