Question

71 LAB 8: Detemination of a Chemical Formula by Titration: Ca with H,O B. Titration of the Calcium-Water Product and Determination of the Chemical Formula of Calcium Hydroxide M C Precise concentration of 0.3 M HCI from T.A.. Trial 2 Trial 1 O.l689 Step 1 of Section II.B Mass of calcium (g) o.18029 Initial burette reading (mL) 0.0mL Step 2 of Section ILB D.OmL Final burette reading (mL) 22.1 mL 21.2mL Step 8 of Section I1.B 21.2mu 22.7 mL o.0028a 9/t.00150 9/e Step 8 of Section II.B Volume of HCI used Moles of calcium consumed Moles of HCI used Ratio of moles of HCI to moles of calcium Calculations Show your calculations below and record your answers in the table above. Using the molar mass for calcium, find the number of moles of calcium used in each trial 1. and record in the table above. Calculate the moles of HCI that were used to complete the titration. 2. 3. Calculate the ratio of moles of HCI used to moles of calcium consumed Moles of HClused Moles of calcium consumed Worksheet

Answer 1

1) moles of Ca = mass/molar mass

For trail 1: moles of Ca = 0.1198/40.08 = 0.00295 moles

For trail 2 : moles of Ca = 0.1802/40 = 0.004505 moles

2) Moles of HCl = molarity×volume/1000

For trail 1 :moles of HCl = 0.3×22.7/1000 = 0.00681 moles

For trail 2 : moles of HCl = 0.3×21.2/1000 = 0.00636 moles

3) For trail 1:

Moles of HCl/moles of Ca = 0.00681/0.00295 = 2.308/1

For trail 2 :

Moles of HCl/moles of Ca = 0.00636/0.004505 = 1.41/1

4) Ratio of HCl : Ca = 2:1

5) Ratio of OH : Ca = 2 : 1

Thus, formula = Ca(OH)2