I am doing the rate of decomposition of calcium carbonate lab, and I have to det

Question

I am doing the rate of decomposition of calcium carbonate lab, and I have to determine the order of HCl for the rate law r=k[HCl]^n. I know the order for HCl in this reaction is 1, but by finding the average rate of volume produced by CO2, for 6 and 2 M HCl, doesn't give me 1 for the order of HCl. Instead, I got 0.5, 0.6, and only 1 trial out of 4 gave me 1. I need to explain this error in my conclusion, but I am not sure how. Is it because the reaction was incomplete since we did it only for 10 mins? If so, why? Thank you.

These are results from guided inquiry ^^

These are results from introductory activity (6 M HCl with 0.5 g CaCO3) ^^^

My group only did 6 M HCl, so we had to borrow 2M data ^^^

(Trial 2) *20 mL of 6M HCl used with 1g of CaCO3 Time (min) Concentration of CaCO3 + HCI (grams) Concentration of CO2 (g) Volume of CO2 (mL) 18.750g 36 mL 0.071g 18.679g 48 mL 18.655g 18.632g 18.611g 18.592g 18.575g 18.560g 18.546g 18.532g 18.521g 0.095g 0.118g 0.139g 0.158g 0.175g 0.19g 0.204g 0.218g 0.229g 60 mL 71 mL 80 mL 89 mL 97 mL 104 mL 111 mL 117 mL 4 6

Explanation / Answer

Rate of decomposition of CaCO3

Errors in measurement of rate comes from the fact that initially all of HCl present would react to form CO2 so, rate can be determined by volume of CO2 or amount of CO2 formed. However, as the reaction progresses, the amount of HCl left in the reactnion is low and thus lower amounts of CO2 would be generated by the system. This would give lower orders with respect to HCl. Running the reaction for shorter times may also lead to similar error which seems to be the case in the above experiment. Shorter times gives lower amounts of CO2 and hence low order for HCl.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.