Calcium is determined gravimetrically by precipitating it as CaC2O4â‹… H2O, followed by isolating the precipitate as CaCO3. The sample to be analyzed is dissolved in 10 mL of water and 15 mL of 6 M HCl. After dissolution, the resulting solution is heated
to boiling, and a warm solution of excess ammonium oxalate is added. The solution is maintained at 80 °C, and 6 M NH3 is added dropwise, with stirring, until the solution is faintly alkaline. The resulting precipitate and solution are removed from the heat and allowed to stand for at least 1 h. After testing the solution for completeness of precipitation, the sample is filtered, washed with 0.1% w/v ammonium oxalate, and dried at 100–120 °C for 1 h. The precipitate is then transferred to a muffle furnace where it is converted to CaCO3 by drying at 500 ± 25 °il a constant weight. (a) Why is the precipitate of CaC2O4⋅ H2O converted to CaCO3? (b) In the final step, if the sample is heated at too high of a temperature, some CaCO3 may be converted to CaO. What effect would this have on the reported %w/w Ca? (c) Why is the precipitant, (NH4)2C2O4, added to a hot, acidic solution rather than to a cold, alkaline

  1. 👍
  2. 👎
  3. 👁
  1. Tthe questions

    1. 👍
    2. 👎
  2. pairnvhhfnjdid

    1. 👍
    2. 👎
  3. The

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    the recommended daily allowance of calcium is 1.2 g. calcium carbonate contains 12.0 % calcium by mass. how many grams of calcium carbonate are needed to provide the rda of calcium

  2. chemistry

    When 11.0 g of calcium metal is reacted with water, 5.00 g of calcium hydroxide is produced. Using the following balanced equation, calculate the percent yield for the reaction? Ca(s) + 2 H2O(l) → Ca(OH)2(aq) + H2(g) 84.0% 12.3%

  3. Chemistry

    A 1.42-g sample of a pure compound, with formula M2SO4, was dissolved in water and treated with an excess of aqueous calcium chloride, resulting in the precipitation of all the sulphate ions as calcium sulphate. The precipitate

  4. Organic Chemistry

    Separation scheme for isolating benzoic acid Could you please show me a separation scheme for isolating benzoic acid from a reaction mixture if mixing a Grignard reagent phenylmagnesium bromide with dry ice (CO2) in ether? Thanks!

  1. Chemistry

    The piperazine content of an impure commercial material can be determined by precipitating and weighing the diacetate: (C2H4)2N2H2 + 2 CH3COOH → (C2H4)2N2H2(CH3COOH)2 In one experiment, 0.3126 gram of the sample was dissolved in

  2. chemistry

    consider the following changes at constant temperature & pressure H2O(s) --yields-- H20(l); Delta H1 H2O(l) --yields-- H2O(g); Delta H2 H2O(g) --yields-- H2O(s); Delta H3 Using Hess's law, the sum of the deltas is a. equal to 0 b.

  3. chemistry

    Calcium carbonate reacts with hydrochloric acid according to the following reaction: CaCO3 (s) + 2 HCl (aq) --> CaCl2 (aq) + H2O (l) + CO2 (g) How many grams of calcium carbonate would be required to neutralize 50.0 cm3 of 8.00 M

  4. chemistry

    Calcium carbide (CaC2) reacts with water to form acetylene (C2H2) gas and calcium hydroxide (Ca(OH)2). If the ΔH for: CaC2(s) + 2H2O(l) = Ca(OH)2(s) + C2H2(g) is -127 kJ, then what is the enthalpy of formation for calcium

  1. chemistry

    Calcium carbonate reacts with phosphoric acid to produce calcium phosphate, carbon dioxide, and water. 3 CaCO3(s) + 2 H3PO4(aq) Ca3(PO4)2(aq) + 3 CO2(g) + 3 H2O(l) How many grams of phosphoric acid react with excess calcium

  2. chemistry

    Calculate the standard entropy change for the reaction of calcium oxide with water to form calcium hydroxide: CaO(s) + H2O(ℓ) → Ca(OH)2(s) at 298 K. ∆S ◦ m ∆H◦ f J K·mol? kJ mol? CaO(s) 39.75 −635.09 H2O(ℓ) 69.91


    CaCO3(s)+2HCl(aq)>CaCl2(aq)+H2O(l)+CO2(g) how many grams of calcium chloride will be produced when 30 g of calcium carbonate are combined with 13 g of hydrochloric acid? Which reactant is in excess and how many grams of this

  4. Chemistry

    1. Calcium carbonate reacts with HCl according to the following equation: 2HCl(aq)+CaCO3(s)→CaCl2(aq)+H2O(l)+CO2(g) How many moles of HCl are in 65 mL of 0.15 M HCl? 2. What mass of calcium carbonate is needed for complete

You can view more similar questions or ask a new question.