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How Much Sodium Bicarbonate Is In the Mixture?
Lab Investigation 14
Chemistry 113 Lab
10/13/2011

1) Method 1: Adding acid
NaHCO3 + HCl → NaCl + CO2 + H2O
a) Unknown mixture of NaCl and NaHCO3
Mass of unknown mixture (NaCl + NaHCO3)| 3 g|
Mass of HCl| 30 .31g|
Mass of products ( NaCl + H2O )| 26.98 g|
Calculate mass of CO2| 6.33g|
Calculate mass of NaHCO3| 12 .1 g|
i) Calculation :
Mass of CO2 =
[Mass of unknown mixture (NaCl + NaHCO3) + Mass of HCl ] – [Mass of NaCl + H2O] = (3 g + 30.31 g) – 26.98 g = 6.33g
Mass of NaHCO3 :
6.33 g CO2 * 1 mol CO2 44.10 g CO2 * 1 mol NaHCO3 1 mol CO2 *84.20 g NaHCO3 1mol NaHCO3 =12. 1 g NaHCO3

b) Purity sodium bicarbonate
Mass of NaHCO3| 3 g|
Mass of HCl| 30 g|
Mass of products ( NaCl + H2O )| 26.81 g|
Calculate mass of CO2| 6. 19 g|
Theoretical mass of NaHCO3| 11. 8 g|
i) Calculation :
Mass of CO2 = ( Mass of NaHCO3 + Mass of HCl ) – ( Mass of NaCl + H2O ) = (3 g + 30 g ) – 26.81 g = 6.19 g
Theoretical mass of NaHCO3 :
6.19 g CO2 * 1 mol CO2 44.10 g CO2 * 1 mol NaHCO3 1 mol CO2 *84.20 g NaHCO3 1mol NaHCO3 =11. 8 g NaHCO3

2) Method 2: Heating
2NaHCO3→Na2CO3+CO2+H2O
a) Experimental results
i) Trial 1
Mass of NaHCO3| 0.3g|
Temperature of hot plate| 400 ˚C|
Time interval| 10 min.|
Mass of mini beaker and product (Na2CO3)| 31.3g|
Mass of mini beaker| 31.21g|
Final mass of Na2CO3| 0.09g|

ii) Trial 2
Mass of NaHCO3| 0.3g|
Temperature of hot plate| 400 ˚C|
Time interval| 10 min.|
Mass of mini beaker and product (Na2CO3)| 31.52g|
Mass of mini beaker| 31.31g|
Final mass of Na2CO3| 0.21g|

iii) Average mass of Na2CO3
(0.09 g + 0.21 g) / 2 = 0.15 g

b) Theoretical results
i) Trial 1
0.3g NaHCO3 * 1mol NaHCO384.0062g NaHCO3 * 1 mol Na2CO32 mol NaHCO3 * 105.99g Na2CO31 mol Na2CO3 = 0.19g Na2CO3 2) Trial 2
0.3g NaHCO3 * 1mol NaHCO384.0062g NaHCO3 * 1 mol Na2CO32 mol NaHCO3 * 105.99g Na2CO31 mol Na2CO3...
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