Three separate aqueous solutions are combined in a beaker at 25 °C:
• 100.0 mL of 0.050 M CaCl2
• 100.0 mL of 0.050 M Sr(NO3)2
• 200.0 mL of 0.10 M K2CO3
Assume volumes are additive and that only carbonate precipitates can form. The solubility‐product constants are Ksp(CaCO3)=4.8×10−9 and Ksp(SrCO3)=1.0×10−10 at 25 °C.
(a) Calculate the initial molar concentrations of Ca2+, Sr2+, and CO32− immediately after mixing but before any precipitation occurs.
(b) Determine the ionic product Q for CaCO3 and for SrCO3 using the concentrations from part (a).
(c) Identify which carbonate, if any, precipitates first. Support your answer with quantitative reasoning.
(d) Assuming only the carbonate identified in part (c) precipitates until its ionic product equals its Ksp, calculate the mass of that carbonate that forms. (Molar masses: CaCO3, 100.1 g mol−1; SrCO3, 147.6 g mol−1.)
(e) Write balanced net ionic equations for each precipitation reaction that is predicted to occur in this system.