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A precipitation reaction is caused by mixing 100. mL of 0.25 M K2Cr2O7 solution with 100. mL of 0.25 M Pb(NO3)2 solution. When the precipitate forms, it is filtered from the mixture.How many moles of solid product are formed?0.025 mol0.050 mol0.25 mol0.010 mol

Respuesta :

Answer: The amount of solid product (lead dichromate) formed is 0.025 moles

Explanation:

To calculate the number of moles for given molarity, we use the equation:

[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}[/tex]     .....(1)

  • For potassium dichromate:

Molarity of potassium dichromate solution = 0.25 M

Volume of solution = 100.0 mL

Putting values in equation 1, we get:

[tex]0.25M=\frac{\text{Moles of potassium dichromate}\times 1000}{100.0}\\\\\text{Moles of potassium dichromate}=\frac{0.25\times 100}{1000}=0.025mol[/tex]

  • For lead nitrate:

Molarity of lead nitrate solution = 0.25 M

Volume of solution = 100.0 mL

Putting values in equation 1, we get:

[tex]0.25M=\frac{\text{Moles of lead nitrate}\times 1000}{100.0}\\\\\text{Moles of lead nitrate}=\frac{0.25\times 100}{1000}=0.025mol[/tex]

The chemical equation for the reaction of potassium dichromate and lead nitrate follows:

[tex]K_2Cr_2O_7(aq.)+Pb(NO_3)_2(aq.)\rightarrow PbCr_2O_7(s)+2KNO_3(aq.)[/tex]

The solid precipitate formed here is lead dichromate

By Stoichiometry of the reaction:

1 mole of lead nitrate produces 1 mole of lead dichromate

So, 0.025 moles of lead nitrate will produce = [tex]\frac{1}{1}\times 0.025=0.025mol[/tex] of lead dichromate

Hence, the amount of solid product (lead dichromate) formed is 0.025 moles