Chemistry Theoretical Yield Question Hwk?
2020-08-07 2:30 pm
Lead ions can be precipitated from solution with NaCl according to the following reaction Pb+2 + 2NaCl _> PbCl2 + 2Na+. When 135.8 g of NaCl are added to a solution containing 195.7 g Pb +2 , a PbCl 2 solid forms. The precipitate is filtered and dried and found to have a mass of 225.4 g. Determine the limiting reactant, theoretical yield of PbCl 2 and percent yield for the reaction
回答 (2)
2020-08-07 4:32 pm
✔ 最佳答案
Molar mass of Pb²⁺ = 207.2 g/molMolar mass of NaCl = (22.99 + 35.45) g/mol = 58.44 g/mol
Molar mass of PbCl₂ = (207.2 + 35.45×2) g/mol = 278.1 g/mol
Initial moles of Pb²⁺ = (195.7 g) / (207.2 g/mol) = 0.9445 mol
Initial moles of NaCl = (135.8 g) / (58.44 g/mol) = 2.324 mol
Equation for the reaction:
Pb²⁺(aq) + 2NaCl → PbCl₂ + 2Na⁺
Mole ratio Pb²⁺ : NaCl = 1 : 2
If Pb²⁺ completely reacts, NaCl needed = (0.9445 mol) × 2 = 1,889 mol < 2.324 mol
Hence, NaCl is in excess, and the limiting reactant is Pb²⁺.
According to the above equation, mole ratio Pb²⁺ : PbCl₂ = 1 : 1
Maximum moles of PbCl₂ yielded = 0.9445 mol
Theoretical yield of PbCl₂ = (0.9445 mol) × (278.1 g/mol) = 262.7 g
Percent yield of the reaction = (225.4/262.7) × 100% = 85.80%
2020-08-07 2:46 pm
steps for YOU to follow
.. (1) write a balanced equation
.. (2) convert everything to moles
.. (3) determine LR
.. (4) convert moles LR to moles other species
.. (5) convert moles back to mass.. this is theoretical mass
.. (6) % yield = (actual mass recovered / theoretical mass) * 100%
.. (1) write a balanced equation
.. (2) convert everything to moles
.. (3) determine LR
.. (4) convert moles LR to moles other species
.. (5) convert moles back to mass.. this is theoretical mass
.. (6) % yield = (actual mass recovered / theoretical mass) * 100%
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