A 4.50 g sample of limestone (impure CaCO3) was dissolved in 0.1M HCl solution according to the following equation.   CaCO3(s) + 2HCl(aq) → CaCl2 (aq) + CO2 (g) + H2O (l)   Excess of (NH4)2C2O4(aq), was added to the resulting solution to precipitate the calcium ions as calcium oxalate, CaC2O4(s). Ca2+(aq) + C2O42-(aq) → CaC2O4 (s)   The precipitate was filtered, dried and weighed at 2.15 g.   (Show your work)                                                                                                 a)    Determine the percentage by mass of calcium carbonate (CaCO3) in the limestone sample. (MM of CaCO3 is 100.09 g/mol)   b) Why we need to dry the precipitate until we get a constant mass?   c) Is the precipitate of calcium oxalate (CaC2O4) stable and in the final form or not? Explain.

The following reaction is a precipitation reaction. NaCl (aq) + AgNO3 (aq) → NaNO3 (aq) + AgCl (s) a metal displacement a decomposition an acid-base neutralization

Apply the concepts of stoichiometry and solution concentration in this section.  Potassium iodide reacts with lead (II) nitrate in the following precipitation reaction 2 KI (aq)  + Pb(NO3)2 (aq)       KNO3 (aq)    +  PbI2 (s). What volume of 0.200 M KI solution is required to completely precipitate all of the lead in 255mL of a 0.312 M Pb(NO3)2 solution?           An solution is made by dissolving 28.4 g of glucose (C6H12O6) in 355 g of water. The final volume of the solution is 378 mL. Calculate the molarity, molality, mole fraction, mole percent and mass percent of the solution,                          Hydrochloric acid is usually purchased in a concentrated form that is 37.0 % HCl by mass and has a density of 1.20 g/mL. Describe exactly how to prepare 2.85 L of a 0.500 M HCl to be used in Dr. Henary’s CHEM1211K lab from the concentrated solution. Hint (Find molarity of concentrated solution and use dilution equation. This is how your solution are prepared)

The amount of I, (aq) in a solution can be determined by titration with a solution containing a known concentration of S₂O3(aq) (thiosulfate ion). The determination is based on the net ionic equation 25,0 (aq) +(aq)- SO (aq) + 31 (aq) Given that it requires 31.9 mL of 0.210 M Na₂S₂O, (aq) to titrate a 10.0 mL. sample of I5 (aq), calculate the molarity of I5 (aq) in the solution. = x10 TOOLS - I M

A 0.450 g sample of impure CaCO,(s) is dissolved in 50.0 mL of 0.150 M HC1(aq). The equation for the reaction is CACO, (s) + 2 HCI(aq) → CaCl, (aq) + H,O(1) + CO,(g) The excess HCl(aq) is titrated by 8.60 mL of 0.125 M NAOH(aq). Calculate the mass percentage of CaCO, (s) in the sample. mass percentage: % Question Source: McQuarrie, Rock, And Gallogly 4e - General Chemsitry Publisher: University Science Books O O 6 hulu 9 MacBook PrO GSearch or type URL % & 4. 6. 8. dele Y. OP H. V MOSISO command option

Normal calcium levels in the blood should be between 9.0 and 10.5 mg/dL. Calcium levels in the blood can be determined by adding oxalate ion to precipitate calcium oxalate, CaC2O4, followed by dissolving the precipitate in aqueous acid and titrating the resulting oxalic acid (H2C2O4) with KMnO4. 5 H2C2O4 (aq) + 2 MnO4–(aq) + 6 H+(aq) yields 10 CO2 (g) + 2 Mn2+(aq) + 8 H2O(l) What is the concentration of Ca2+ (mg/dL) in a 10.0 mL sample of blood if 10.54 mL of 9.88 x 10–4 M KMnO4 solution is needed for the titration.

To measure the amount of calcium carbonate (CaCO3) in a seashell, an analytical chemist crushes a 4.30 g sample of the shell to a fine powder and titrates it to the endpoint with 233. mL of 0.2700M hydrogen chloride (HCI) solution. The balanced chemical equation for the reaction is: 2HCl(aq) + CO3(aq) → H₂CO3(aq) + 2Cl(aq) 19 0 What kind of reaction is this? O precipitation O acid-base redox X olo If you said this was a precipitation reaction, enter the chemical formula of the precipitate. 0 Ar If you said this was an acid-base reaction, enter the chemical formula of the reactant that is acting as the base. If you said this was a redox reaction, enter the chemical symbol of the element that is oxidized. Calculate the mass percent of CaCO3 in the sample. Be sure your answer has 3 significant digits. П 0 0% S ?

The following chemical reaction takes place in aqueous solution: CuBr2 (aq) + 2NaOH (aq) → CuOH2 (s) + 2NaBr (aq) Write the net ionic equation for this reaction.

Potassium hydrogen phthalate (KHP, HC8H4O4K) is used to standardize sodium hydroxide. If 25.00 mL of NaOH (aq) is required to titrate 0.8500 g KHP to the equivalence point, what is the concentration of the NaOH(aq)? (The molar mass of KHP = 204.2 g/mol) HC8H4O4-(aq)  +  OH-(aq)  →  C8H4O42-(aq)  +  H2O

The amount of I3 (aq) in a solution can be determined by titration with a solution containing a known concentration of S₂O3(aq) (thiosulfate ion). The determination is based on the net ionic equation 2 S₂O3(aq) + 13(aq) - S₂O²(aq) + 31¯(aq) Given that it requires 37.4 mL of 0.470 M Na₂S₂O3(aq) to titrate a 25.0 mL sample of 13 (aq), calculate the molarity of I3 (aq) in the solution. [¹] : 0.159 Incorrect M