Purpose: Teach us to count moles of reaction formulas and dettas to determine mass of reactants.
Introduction: By heating sodium carbonate and consider this to be the mass of the substance formed is taken out.
By knowing the masses of the reactants to a reaction formulas 1-3 determined as the one for heating the sodium bicarbonate.
Material: Libra, pot, burner and calcium carbonate.
Execution: The crucible was weighed empty.
The salt was added to and weighed.
2g salt added in and this was taken out of the mass of salt + pot subtracted by the mass of only the crucible.
The materials were developed for the heating burner was turned on.
The crucible was carefully treated with a "clamp" to grab the crucible, in order that we would not take it with your fingers.
The natural fat on our fingers could come in the crucible where everything will react.
The salt is heated for a long time.
We weighed crucible and salt in. When heated, vaporized certain substances labeled as the wave of mass has decreased.
To know that the salt has reacted ready and so we can calculate the correct numbers so was the crucible had to be warmed a little, and weighed again.
If this weighting is the same mass as the first one can start counting on the formula but if the mass has changed since last weighing, it must be heated and weighed to the mass has not changed.
This was done three times in our experiments.
The result of the mass when we weighed the last time was used to determine how much is gasified. We do this by taking as much as salt + crucible weighed initially subtracted by as much salt and crucible weighed when we had heated it. The difference in between I use when I said find out the mass salt reacted. By taking the number of grams of salt weighed initially subtracted by the difference in the last calculation, ie the one that does not remain in the crucible after heating, I get the difference in mass, grams. Then the task is to find out what was left in the crucible after heating was on topic. This could be calculated by taking the salt mass from the beginning subtracted the difference before and after heating in mass. This is then compared with the masses of the topics below to arrive at conclusions and results.
Calculations: 16.56 g pot
Crucible + salt = 18.56 g
Mass salt = 18.56 to 16.56 = 2g
Pulp salt reacted and was somewhat out of the following subjects:
18.56 to 17.81 g = 0.74 2 to 0.74 g
The salt I heats
M (NaHCO3) 22.99 +1.0079 +12.011 +16 x 3 = 84.0089 g / mol
n (NaHCO3) 2g/84, 0089g/mol = 0.02381 mol
Here are three suggestions for reactions
First M (NaOH) 22.99 +16 +1.0079 = 39.9979 g / mol
n (NaOH) 0.02381 mole
m (NaOH) x 0.02381 39.9979 g = 0.9523
M (Na2O) 22.99 x 2 +1.0079 = 61.98 g / mol
n (Na2O) 0.02381 / 2 = 0.0119 mol
m ((Na2O) 0.0119 x 61.98 = 0.7376 g
M (Na2CO3) 22.99 +12.011 x 2 +16 x 3 = 105.991 g / mol
n (Na2CO3) 0.02381 / 2 = 0.0119 mol
m (Na2CO3) 0.0119 x 105.991 = 1.2613 g
Crucible: 16.56 g
Crucible + salt: 18.56 g
First weighing after heating: 17.84 g
Other weighting: 17.81 g
Third weighing: 17.81 g
The pulp which had been gas: 0.74 g
Massa was left: 1.26 g
Substance Molar mass (g / mol) Amount of substance (mol) Mass (g)
Sodium bicarbonate NaHCO3 84.0089 0.02381 2
NaOH 39.9979 0.02381 0.9523
Na2O 61.98 0.0119 0.7376
Na2CO3 105.991 0.0119 1.2613
The mass in the crucible could be compared to option number three. The masses were consistent. The substance formed in the crucible when heating was sodium carbonate.
The three options showed two reactions with a product that is formed of two. This means that the reactants are half of the product. Therefore, it is important that the calculation dividing the amount of substance to two. Carbon dioxide and water created by the heating of sodium bicarbonate, which we can not see with the naked eye. Therefore, we could only distinguish between the three options of equations by counting on them. The substance would remain regardless of the subject that would be formed by these three options is the same color when heated as sodium bicarbonate showed us from the beginning, white powder. The other substances that become gaseous, one can not see. Therefore, we arrived at our conclusion by counting. (Hard to write a conclusion on this lab as it was to count their way to the correct answer)