A 10.231-g sample of window cleaner containing ammonia was diluted with 39.466 mL of 0.1063 M HCl to reach the bromocresol green end point. Find the weight percent of NH3 (FM 17.031) in the cleaner.
mols HCl = M x L = ?
moles HCl = moles NH3
g NH3 = moles x molar mass.
%NH3 = (mass NH3/mass sample)*100 = ?
To find the weight percent of NH3 in the cleaner, we need to calculate the number of moles of NH3 and the weight percent.
First, let's calculate the number of moles of NH3 in the 39.466 mL of 0.1063 M HCl solution.
moles of HCl = Molarity × Volume (in L)
moles of NH3 = moles of HCl (from the balanced equation)
Since the balanced equation between HCl and NH3 is:
HCl + NH3 → NH4Cl
We know that 1 mole of HCl reacts with 1 mole of NH3.
moles of HCl = 0.1063 M × 0.039466 L = 0.004192 moles
Therefore, the moles of NH3 in the 39.466 mL of 0.1063 M HCl solution is also 0.004192.
Now let's find the weight percent of NH3 in the cleaner.
Weight percent = (moles of NH3 × molar mass of NH3) / (mass of sample) × 100
mass of sample = 10.231 g
Weight percent = (0.004192 moles × 17.031 g/mol) / (10.231 g) × 100
Weight percent = (0.07139 g) / (10.231 g) × 100
Weight percent ≈ 0.697%
Therefore, the weight percent of NH3 in the cleaner is approximately 0.697%.
To find the weight percent of NH3 in the cleaner, we first need to calculate the moles of NH3 and the total weight of the sample.
1. Calculate the moles of HCl used:
Moles of HCl = Molarity of HCl × Volume of HCl used
Moles of HCl = 0.1063 mol/L × 0.039466 L
2. Convert the moles of HCl to moles of NH3:
Since HCl reacts with NH3 in a 1:1 ratio, the moles of HCl used is equal to the moles of NH3 present.
Moles of NH3 = Moles of HCl = 0.1063 mol/L × 0.039466 L
3. Calculate the moles of NH3 in the entire sample:
Moles of NH3 in the sample = Moles of NH3 in the diluted solution / Dilution factor
Dilution factor = Volume of diluent / Volume of sample
Volume of diluent = 39.466 mL = 0.039466 L
Volume of sample = Volume of diluent + Volume of HCl used = 0.039466 L + 0.039466 L
Dilution factor = 0.039466 L / (0.039466 L + 0.039466 L)
4. Calculate the moles of NH3 in the entire sample:
Moles of NH3 in the sample = 0.1063 mol/L × 0.039466 L / (0.039466 L + 0.039466 L)
5. Calculate the weight of NH3 in the sample:
Weight of NH3 = Moles of NH3 × Molar mass of NH3
Molar mass of NH3 = 17.031 g/mol
Weight of NH3 = Moles of NH3 × 17.031 g/mol
6. Calculate the weight percent of NH3 in the sample:
Weight percent of NH3 = (Weight of NH3 / Total weight of the sample) × 100
Now, substitute the values into the formulas to find the weight percent of NH3 in the cleaner.