posted by Heather
Sodium phosphate reacts with copper (II) chloride in a precipitation
reaction. What mass (in grams) of the precipitate will form when 325 mL of 0.5000 molar sodium phosphate reacts with 41.5 cL of 0.6000 molar copper (II) chloride.
This is a limiting reagent problem. How do I know? Because BOTH reactants are given.
1. Write the equation and balance it.
2. Convert Na3PO4 to moles. moles = M x L.
3. Convert CuCl2 to moles. same process.
4. Using the coefficients in the balanced equation, convert moles Na3PO4 to moles of the product.
5. Same process, convert moles CuCl2 to moles of the product.
6. It is quite likely that the answers from steps 4 and 5 will not agree which means one of them is wrong. The correct answer, in limiting reagent problems, is ALWAYS the smaller one and the reagent producing that number is the limiting reagent.
7. Now convert moles of the value from step 7 to grams. g = moles x molar mass.