at elevated temperature, NaHCO3 (83.98g/mol) is converted quantitatively to Na2CO3 (105.98g/mol).Ignition of 0.3592g sample of an antacid tablet containing NaHCO3 and non volatile impurities yielded a residue weighing 0.2362g. Calculate the percent purity of the sample.
92.76% purity
60.25% purity
To calculate the percent purity of the sample, we need to determine the amount of NaHCO3 present in the tablet and compare it to the total amount of residue obtained.
1. Calculate the amount of NaHCO3 in the tablet:
NaHCO3 molecular weight = 83.98 g/mol
Mass of NaHCO3 in the tablet = 0.3592 g
Number of moles of NaHCO3 = Mass / Molecular weight
= 0.3592 g / 83.98 g/mol
2. Calculate the amount of Na2CO3 formed:
Na2CO3 molecular weight = 105.98 g/mol
Number of moles of Na2CO3 formed = Number of moles of NaHCO3
3. Calculate the mass of Na2CO3 formed:
Mass of Na2CO3 formed = Number of moles of Na2CO3 * Molecular weight
= (0.3592 g / 83.98 g/mol) * 105.98 g/mol
4. Calculate the percent purity:
Percent purity = (Mass of Na2CO3 formed / Mass of residue) * 100
= (Mass of Na2CO3 formed / 0.2362 g) * 100
Plug in the calculated values to find the percent purity.
To calculate the percent purity of the sample, we need to determine the amount of NaHCO3 in the tablet and compare it to the maximum possible amount based on the residue obtained after ignition.
First, let's calculate the amount of NaHCO3 in the residue:
Amount of residue = mass of the sample - mass of the residue
Amount of residue = 0.3592g - 0.2362g
Amount of residue = 0.123g
Next, we need to convert this amount to moles of NaHCO3 using its molar mass:
Moles of NaHCO3 = Amount of residue / molar mass of NaHCO3
Moles of NaHCO3 = 0.123g / 83.98g/mol
Moles of NaHCO3 = 0.001464 mol
Since NaHCO3 is converted quantitatively to Na2CO3, the amount of NaHCO3 in the residue is also equal to the amount of Na2CO3 formed.
Now, let's calculate the maximum possible amount of NaHCO3 in the sample:
Maximum amount of NaHCO3 = Moles of NaHCO3 = 0.001464 mol
Finally, we can calculate the percent purity:
Percent purity = (Actual amount of NaHCO3 / Maximum amount of NaHCO3) x 100
Percent purity = (0.001464 mol / 0.001464 mol) x 100
Percent purity = 100%
Therefore, the percent purity of the sample is 100%.