Table salt, NaCl(s), and sugar, C12H22O11(s), are accidentally mixed. A 4.00-g sample is burned, and 3.30 g of CO2(g) is produced. What was the mass percentage of the table salt in the mixture?
Convert 3.30 g CO2 to g C12H22O11. The easy to do that, which isn't taught in schooles these days, is
3.30 x (molar mass C12H22O11/12*molar mass CO2) = about 3.30 x (342/12*44) = about 2 grams but you need to be more accurate than that.
Then mass NaCl = 4.00-about 2 = about 2 g NaCl.
%NaCl = (mass NaCl/mass sample)*100 = ?
To find the mass percentage of the table salt (NaCl) in the mixture, we need to calculate the mass of NaCl burned in the 4.00 g sample.
First, we need to determine the number of moles of CO2 produced when 3.30 g of CO2 is generated. We can use the molar mass of CO2 to convert grams to moles.
The molar mass of CO2 is calculated by adding the atomic masses of one carbon atom and two oxygen atoms:
Molar mass of CO2 = (12.01 g/mol) + 2(16.00 g/mol) = 44.01 g/mol
Now, we can calculate the number of moles (n) of CO2 produced:
n = mass / molar mass = 3.30 g / 44.01 g/mol
Next, we need to determine the number of moles of NaCl that can produce the same amount of CO2. The balanced chemical equation for the combustion of NaCl is:
2 NaCl(s) + 2 O2(g) → 2 NaClO(s) + Cl2(g)
As per the balanced equation, two moles of NaCl produce one mole of CO2. Therefore, the number of moles of NaCl (n_NaCl) can be calculated as:
n_NaCl = 0.5 * n
Now, we can find the mass of NaCl using its molar mass:
Molar mass of NaCl = (22.99 g/mol) + (35.45 g/mol) = 58.44 g/mol
Mass of NaCl = n_NaCl * molar mass of NaCl = (0.5 * n) * 58.44 g/mol
Finally, we can calculate the mass percentage of NaCl in the mixture using the mass of NaCl and the total mass of the sample.
Mass percentage of NaCl = (Mass of NaCl / Mass of the sample) * 100
Substituting the calculated values:
Mass percentage of NaCl = [(0.5 * n) * 58.44 g/mol / 4.00 g] * 100
Calculate the final answer to find the mass percentage of NaCl in the mixture.