Exp. 2 Gravimetric Determination of Calcium as Ca C2O4 ⋅ H2O PDF

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CHEM 222 Exp. 2: Gravimetric Determination of Calcium as CaC2O4 ⋅ H2O Name: Renad Damooni TA s Name: Thomas McLaughlin

1 Date: 02/14/2022

PRE-LAB Answer all questions on one page to submit to gradescope: Q1 2NH4+ (aq) + C2O42- (aq) +2H+ (aq) +2Cl-(aq) → 2NH4+ (aq) + 2Cl- (aq) + H2C2O4 (aq)

Q2 CaCO3(s) + 2HCl (aq) → H2O (l) + CO2 (g) + CaCl2 (aq) H2CO3 → CO2 + H2O Ionic Compound: CaCl2 → Ca 2+ + 2Cl-

Q3 Water (H2O) and CaCl2 (calcium chloride) will present in solution and CO2 will give off

Q4 CaCl2 (aq) + C2H8N2O4 (aq) → CaC2O4 + 2NH4Cl (aq)

Q5 reaction involved: CaCl2 (aq) + (NH4)2C2O4 (aq) → CaC2O4(s) + 2NH4Cl (aq) Equiv. Constant (K) = [NH4Cl]2 / [CaCl2] [(NH4)2C2O4]] If we add CaCl2 then [CaCl2] will increase which cause k to decrease but as k is function if temp, hence for maintaining it constant reaction will shift in forward direction then [CaCl2] will decrease but precipitate CaC2O4 will increase.

CHEM 222 Exp. 2: Gravimetric Determination of Calcium as CaC2O4 ⋅ H2O Name: Renad Damooni TA s Name: Thomas McLaughlin

2 Date: 02/14/2022

Chem Collective Procedural steps: 1. Prepare the materials needed Chemicals – AgNO3 NaCl Solution 3 (100.64) 2. Add 10mL of Solution 3(10% of AgNO3) in the 250mLBeaker 3. Then add 100g of NaCl into the beaker 4. We must wait until the NaCl is no longer reacting to the solution. The mass of AgCl is also indicated which results to 0.2363g AgCl. 5. Solve for the mass of 10% AgNO3 So, to find out how much AgNO3 is in a solution AgNO3 (aq) + NaCl (aq) → NaNO3 (aq) + AgCl (s) Volume of solution = 100.64mL AgNO3 → ? NaCl – 95.6196 AgCl – 0.236388 Molar mass AgNO3 – 169.87 AgCl – 143.22 Calculations: Solution: 0.236388 g AgCl x 1 mol of AgCl/143.22 g AgCl x 1 mol of AgNO3/1 mol AgCl x 169.87g AgNO3/ 1 mol AgNO3= 0.28037g AgNO3 this is only the 10% of the actual solution. 10% = 2.81g AgNO3 Insert certificate of compeletion/screenshot

CHEM 222 Exp. 2: Gravimetric Determination of Calcium as CaC2O4 ⋅ H2O Name: Renad Damooni TA s Name: Thomas McLaughlin

3 Date: 02/14/2022

UNKNOWN #: ___________ trial 1

trial 2

trial 3

33.17

33.20

26.0

funnel + precipitate weight (g) 34.30

36.61

27.60

empty funnel weight (g) precipitate weight (g)

1.20

3.50

1.60

molarity of Ca2+

3.302 E-7

9.390E-7

4.325 E-7

average molarity

5.672E-7

std. dev. of molarity

2.662E-7

relative std. dev. of molarity

57.47 %

g CaCO3/L

6.420 E -5 1.372 E-4

4.680 E-5

average g CaCO3/L

8.273 E-5

Post-LAB Answer all questions on one page to submit to gradescope (include scan of notebook at end): Q1 Reaction of Ammonium oxalate with HCl (NH4)2C2O4 + 2HCl → 2NH4Cl + H2C2O4

Q2 When HCl is added to Ammonium Oxalate NH4Cl (NH4+ & Cl-) & H2C2O4 + (Oxalic acid) is formed a chemical & physical changes redox displacement reaction O ll Q3 H2N – C -NH2 + H2O → 2 NH3 + CO3 Enzyme...