The first chemical added to HCl was Na2CO3(s) and bubbles were formed as soon as the Sodium Anhydrous Carbonate powder was added. The color of the reaction looked like a light purple violent color. There was no specific smell to the reaction but the reaction caused gases to form. It took about 120 seconds for the reaction to end and it was evident by looking at the solution. It looked like a cloudy white liquid. In the Sodium hydrogen carbonate reaction there was extreme reaction in that a lot of bubbles formed therefore NaHCO3(s) powder had to be slowly poured inside the calorimeter.
Title: Raw data table of minimum and maximum temperature, mass and molar mass of Sodium Anhydrous Carbonate and Sodium hydrogen carbonate.
Name of Compound: | Formula: | Mass,m/g (±0.001g): | Molar Mass, Mr/gmol-1 | Initial Temperature (±0.01 °C) | Final Temperature (±0.01°C) |
Sodium Anhydrous Carbonate | Na2CO3(s) | 14.00 | 106.00 | 21.41 | 22.69 |
Sodium hydrogen carbonate | NaHCO3(s) | 8.00 | 84.00 | 20.23 | 11.52 |
Endothermic reaction: NaHCO3(s) + HCl → NaCl(aq)+CO2(g)+ H2O
q = (100g) X (4.18Jg-1k-1) X (8.71K) /1000 = 3.64 kJ mol-1
... dependent variable is the mass of the sodium carbonate. The controls used in the experiment are the indicators used, the temperature of the solution ... 2 moles of HCl added per 1 mole of carbonate. Meaning the reaction reached completion according to the final theoretical expression presented ...
NaHCO3(s) =14g/ 84g=0.17mol of NaHCO3(s)
HCl= 100g/36g=2.78 mol of HCl
△H =3.64 /0.17= 21.41 kJ mol-1
Exothermic reaction: Na2CO3(s) + 2HCl → 2NaCl (aq) +CO2 (g) + H2O
q = (100g) X (4.18Jg-1k-1) X (1.28K) /1000= 0.54 kJ mol-1
Na2CO3(s) =8g/106g=0.075 mol of Na2CO3(s)
HCl=100g/36g=2.78 mol of HCl
△H =0.54/0.075 =-7.13 kJ mol-1
1. NaHCO3(s)+ HCl → NaCl(aq)+CO2(g)+ H2O
Na2CO3(s) + 2HCl → 2NaCl (aq) +CO2 (g) + H2O
2. (NaHCO3(s)+ HCl → NaCl(aq)+CO2(g)+ H2O)ｘ2
-(Na2CO3(s) + 2HCl → 2NaCl(aq) +CO2(g)+ H2O)
3. 2NaHCO3(s)+ 2HCl → 2NaCl(aq)+2CO2(g)+ 2H2O
2NaCl(aq) +CO2(g)+ H2O→ Na2CO3(s) + 2HCl
5. 2NaHCO3(s) → Na2CO3(s) + CO2(g)+ H2O
6. ∴ NaHCO3(s) →12Na2CO3(s) + 12CO2(g)+ 12H2O
(21.41 kJ mol-1) X 2 – (-7.13 kJ mol-1)
=49.95 kJ mol-1
Percent Uncertainty Calculation:
Percent Uncertainty of 100 cm3 Graduated Cylinder: 0.5 / 90 * 100 = 0.56 %
%error= 90-X90×100= 90-49.9590×100=44.5%
Mass of HCl: 0.1100×100=0.1%
Mass of Sodium hydrogen carbonate: 0.00114×100= 0.007%
Mass anhydrous sodium carbonate: 0.0018×100=0.0125%
∴ Random Error: 17.4%±2
49.95 %-17.4% = 32.55%
∴ Systematic error: 32.55%
The given theoretical value for the experiment is 90 kJ mol-1. However, the experimental value resulted as 49.95. There is a huge difference between the value from the experiment and the value that was given. The difference between the experimental and theoretical value is about 40.05. Therefore by the calculation, there was an about 44.05% total uncertainty, which is a high percentage of error. Out of the 44.05% of errors, about 17.4% are random errors and 29.87% are systematic errors. Therefore there is about 17.4% of error which happened from uncertainties of the equipments and the other 29.87% is errors from the process of the experiment.
... experiment to get accurate results What error is introduced in a mass determination if the object being weighed ... t measure its mass without gravity. Explain the following. Weigh approximately 5 grams of NaCl to the nearest ... milligram. The weight of 5 grams of NaCl is equal to 5,000 milligrams. We ... different balances. When doing experiments we determine the mass my measuring the sample with a balance. ...
Sources of Error: | Ways to Improve: |
Calorimeter: giving off heat to the surrounding | We can reduce the amount of heat being escaped from the calorimeter by simply not opening the cap of the calorimeter often. And when it is necessary to open it, then the process should be fairly quick. Then the amount of heat loss can be reduced. |
Pouring the right amount of HCl, NaHCO3(s), Na2 CO3(s) when weighing | This is an inevitable random error that experimenters can avoid. However, it is possible to reduce the amount of error. Becareful in placing the powder chemicals so thatit doesn’t fall onto the bottom. Make sure to diligently try to get as close to the expected amount. It is recommended to do this procedure as slowly as possible. |
Making sure that the temperature probe is in the right position inside the calorimeter. | Make sure that the experiment is measured by the same temperature probe at all measurement. And when dealing with different chemicals make sure to wash the temperature probe so that it doesn’t affect the reaction. Also the position of the temperature probe may affect the data. Make sure it is positioned fairly close to where it is measured every trial. |