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How much precipitate is produced when 35.0 mL of 0.255 M NaCl is added to 45.0 mL of 0.328 M Pb(NO3)2.

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Answer:

1.24g of precipitate are produced

Step-by-step explanation:

The reaction of NaCl with Pb(NO₃)₂ is:

2 NaCl + Pb(NO₃)₂ → 2 NaNO₃ + PbCl₂(s)

Where 2 moles of NaCl reacts with 1 mole of Pb(NO₃)₂ to produce 1 mole of PbCl₂, the precipitate.

To know how much PbCl₂ is formed we need to determine the moles of NaCl and Pb(NO₃)₂:

Moles NaCl:

35.0mL = 0.0350L * (0.255mol / L) = 8.925x10⁻³ moles NaCl

Moles Pb(NO₃)₂:

45.0mL = 0.0450L * (0.328mol / L) = 0.01476 moles Pb(NO₃)₂

For a complete reaction of 0.01476 moles Pb(NO₃)₂, you require:

0.01476 moles Pb(NO₃)₂ * (2 moles NaCl / 1 mol Pb(NO₃)₂) = 0.02952 moles NaCl.

As you have just 8.925x10⁻³ moles, NaCl is limiting reactant.

And moles of PbCl₂ produced are:

8.925x10⁻³ moles NaCl * (1mol PbCl₂ / 2 moles NaCl) =

4.4625x10⁻³ moles PbCl₂ are formed.

In grams, (Using molar mass PbCl₂: 278.1g/mol):

4.4625x10⁻³ moles PbCl₂ * (278.1g / mol) =

1.24g of precipitate are produced

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