A 0.4671g sample containing sodium bicarbonate (a mono acidic base) is dissolved and titrated with standard solution of HCl acid requiring 40.72cm^3. ( the HCL was standardized by titrating 0.1876NaCO3 which required 37.86cm^3 of acid). Calculate the percent NaCO2 in the sample
The HCl was standardized with what? You have NaCO3 and that can't be. Is it NaHCO3 or Na2CO3. If Na2CO3 I must know what was used for the indicator.
To calculate the percent NaCO3 in the sample, we first need to determine the number of moles of NaCO3 consumed during the titration. Then we can use this information to calculate the percent NaCO3.
Let's break down the steps to get the answer:
Step 1: Calculate the number of moles of HCl used in the titration of NaCO3.
From the given information, the volume of HCl used in the titration of NaCO3 is 37.86 cm^3, and the molar concentration of HCl is not given. However, we can use the information given in the titration of the sample to determine the molar concentration of HCl.
Step 2: Calculate the molar concentration of HCl.
To find the molar concentration of HCl, we need to use the definition of molarity, which is moles of solute divided by the volume of the solution in liters. In the titration of the sample, we know that 40.72 cm^3 of HCl was used to neutralize the NaCO3. Since 1 cm^3 is equal to 1 mL, we can convert the volume to liters by dividing by 1000:
40.72 cm^3 = 40.72 / 1000 = 0.04072 L
Now we have the volume of HCl used in the titration, but we still need the number of moles of HCl. We can use the molar concentration formula:
Molarity (M) = Moles of solute / Volume of solution (in L).
Rearranging the formula, we have:
Moles of solute = Molarity (M) x Volume of solution (in L)
Substituting the values we have:
Moles of HCl = Molarity (M) x Volume of solution (in L)
Moles of HCl = Molarity (M) x 0.04072 L
Step 3: Calculate the molar concentration of NaCO3.
From the information given, the volume of HCl used in the titration of NaCO3 is 37.86 cm^3. Using the same conversion as before, we can convert the volume to liters:
37.86 cm^3 = 37.86 / 1000 = 0.03786 L
We can calculate the molar concentration of NaCO3 using the same formula as before:
Moles of solute = Molarity (M) x Volume of solution (in L)
Moles of NaCO3 = Molarity (M) x 0.03786 L
Step 4: Calculate the number of moles of NaCO3 in the sample.
To do this, we need to use the stoichiometry of the reaction between NaCO3 and HCl. From the balanced equation, we know that one mole of NaCO3 reacts with one mole of HCl. Therefore, the number of moles of NaCO3 in the sample is equal to the number of moles of HCl used in the titration.
Number of moles of NaCO3 in the sample = Moles of HCl used in the titration
Step 5: Calculate the mass of NaCO3 in the sample.
The molar mass of NaCO3 can be calculated by adding the atomic masses of sodium (Na), carbon (C), and oxygen (O):
Na: 22.99 g/mol
C: 12.01 g/mol
O: 16.00 g/mol
Molar mass of NaCO3 = (22.99 + 12.01 + 3 * 16.00) g/mol
The mass of NaCO3 in the sample can be calculated using the formula:
Mass of NaCO3 = Number of moles of NaCO3 in the sample x Molar mass of NaCO3
Step 6: Calculate the percent NaCO3 in the sample.
The percent NaCO3 in the sample can be calculated using the formula:
Percent NaCO3 = (Mass of NaCO3 in the sample / Mass of the sample) x 100
By following these steps, you should be able to calculate the percent NaCO3 in the sample. Remember to substitute the values and units correctly to get the accurate result.