10. During the process of titration of antacid made of calcium carbonate, the fi

Question

10. During the process of titration of antacid made of calcium carbonate, the first step is to add excess hydrochloric acid to antacid to observe bubbling, which is forming carbon dioxide. CaC0;(s) + 2HCl(aq) CaCl2(aq) + CO2(g)+ H2O() Because this carbon dioxide reacts with water to form carbonic acid and increase the overall concentration of acids, removing carbon dioxide is an essential process for an accurate experiment. a) You are given a 1.60 g antacid tablet, et-found thatthe 0.014 moles of HCI is used eteetrto titrate calcium carbonate msteadof exeess-hydreehtorie-acid how many grams of CacoYou had in your tablet? (4 pts) b) What percentage of the sample given to you is CaCO,? (2 pts) c) Draw the Lewis formulas of all resonance forms of carbon dioxide and indicate which onde Co is preferred and explain why. (3 pts) 2 Two students draw the Lewis formula of carbonic acid as follows. Explain what is wrong with these formulas, and suggest right formula of carbonic acid d)

Explanation / Answer

a)

m = 1.6 g of antacid

mol of HCl = 0.014

mol of CaCO3 = 1/2*mol of Hcl = 0.007

mass of CaCO3 = mol*MW = 0.007*100 = 0.7 g of CaCO3

b)

% CaCO3 = mass of CaCO3/total mass * 100%

% CaCO3 = 0.7/1.6*100

% CaCO3 =43.75%

c)

CO2 has no resonances

O=C=O is the most stable species

d)

Typical errors:

excess electrons, missing bonds/electrons

i)

correct

ii) incorrect, due to double bonds in Oxygen

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

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