35.8g of a mixture of potassium chloride and potassium trioxochlorate(v), we're heated to a constant mass. If the residue weighs 24.9g.what was the percentage mass of the potassium chloride in the mixture (k=39, cl=35.5, o=16)
I assume you mean potassium chlorate instead of that screwy name you have for KClO3. The idea behind this problem is that the KClO3 decomposes to oxygen and KCl. The difference between initial and final weight will be the loss in O2. Convert that to mass KClO3 initially. Then difference between mass KClO3 and initial mass is mass KCl.
%KCl = (mass KCl/35.7)*100 = ?
Post your work if you get stuck.
Decomposition KClO3 is
2KClO3 ==> 2KCl + 3O2
To find the percentage mass of potassium chloride (KCl) in the mixture, we need to determine the mass of KCl and divide it by the mass of the mixture, then multiply by 100.
Given:
Mass of the mixture = 35.8 g
Residue after heating = 24.9 g
To calculate the mass of KCl, we need to find the mass of potassium trioxochlorate(v) (KClO3) in the mixture and subtract it from the mass of the mixture.
Step 1: Find the molar mass of KClO3 and KCl.
- Molar mass of KClO3 = (1 × atomic mass of K) + (1 × atomic mass of Cl) + (3 × atomic mass of O)
= (1 × 39) + (1 × 35.5) + (3 × 16)
= 122.5 g/mol
- Molar mass of KCl = atomic mass of K + atomic mass of Cl
= 39 + 35.5
= 74.5 g/mol
Step 2: Calculate the amount of KClO3 in the mixture.
- We know the mass of the mixture (35.8 g), so we need to find the number of moles of KClO3 using its molar mass.
- Number of moles = Mass / Molar mass
= 35.8 g / 122.5 g/mol
≈ 0.292 mol (approximately)
Step 3: Calculate the mass of KClO3.
- Mass of KClO3 = Number of moles × Molar mass
= 0.292 mol × 122.5 g/mol
≈ 35.8 g (approximately)
Step 4: Calculate the mass of KCl.
- Mass of KCl = Mass of the mixture - Mass of KClO3
= 35.8 g - 24.9 g
= 10.9 g
Step 5: Calculate the percentage mass of KCl in the mixture.
- Percentage mass of KCl = (Mass of KCl / Mass of the mixture) × 100
= (10.9 g / 35.8 g) × 100
≈ 30.5%
Therefore, the percentage mass of potassium chloride (KCl) in the mixture is approximately 30.5%.
To find the percentage mass of potassium chloride (KCl) in the mixture, we first need to determine the masses of potassium chloride and potassium trioxochlorate(V) (KClO3) separately.
Let's start by finding the mass of potassium chloride (KCl):
1. Calculate the molar mass of KCl:
- The molar mass of potassium (K) = 39 g/mol
- The molar mass of chloride (Cl) = 35.5 g/mol
- Therefore, the molar mass of KCl = 39 + 35.5 = 74.5 g/mol
2. Use the molar mass to calculate the moles of KCl:
- Moles (n) = Mass (m) / Molar mass (M)
- Moles of KCl = Mass of KCl / Molar mass of KCl
Next, let's calculate the mass of potassium trioxochlorate(V) (KClO3):
3. Subtract the mass of KCl from the total residue mass:
- Mass of KClO3 = Total mass of the residue - Mass of KCl
Now, let's calculate the percentage mass of KCl:
4. Calculate the total mass of the mixture:
- Total mass of the mixture = Mass of KCl + Mass of KClO3
5. Calculate the percentage mass of KCl:
- Percentage mass of KCl = (Mass of KCl / Total mass of the mixture) * 100
Plug in the given values to determine the percentage mass of KCl:
- Mass of KCl = 35.8g - 24.9g
- Mass of KClO3 = 24.9g
- Total mass of the mixture = Mass of KCl + Mass of KClO3
After calculating these values, perform step 5 to find the percentage mass of KCl.