A 18.46 g sample of a compound contains 5.89 g potassium (K), 5.34 g chlorine (Cl), and oxygen (O). Calculate the empirical formula.
is the answer KClO3?
Yes
To determine the empirical formula, we need to calculate the mole ratio of each element present in the compound.
First, we need to calculate the moles of each element present in the compound. This can be done using the given masses and the molar masses of the elements.
The molar mass of potassium (K) = 39.10 g/mol
The molar mass of chlorine (Cl) = 35.45 g/mol
The molar mass of oxygen (O) can be calculated using the total mass of the compound minus the masses of K and Cl.
Mass of K + Cl = 5.89 g + 5.34 g = 11.23 g
Mass of O = 18.46 g - 11.23 g = 7.23 g
Now, let's calculate the moles.
moles of K = mass of K / molar mass of K = 5.89 g / 39.10 g/mol = 0.150 moles
moles of Cl = mass of Cl / molar mass of Cl = 5.34 g / 35.45 g/mol = 0.150 moles
moles of O = mass of O / molar mass of O = 7.23 g / (16.00 g/mol) = 0.452 moles
Next, we need to find the mole ratio by dividing the moles of each element by the smallest number of moles we calculated.
Mole ratio of K = 0.150 moles / 0.150 moles = 1
Mole ratio of Cl = 0.150 moles / 0.150 moles = 1
Mole ratio of O = 0.452 moles / 0.150 moles = 3.01 ≈ 3
Finally, we have the mole ratio for each element in the compound: K:Cl:O ≈ 1:1:3. Thus, the empirical formula is KClO3, confirming your answer.
To determine the empirical formula of a compound, you need to find the ratio of the elements present in the compound. Here's how you can do that:
1. Convert the mass of each element to moles using their atomic masses:
- Potassium (K): 5.89 g / 39.10 g/mol = 0.1502 mol
- Chlorine (Cl): 5.34 g / 35.45 g/mol = 0.1505 mol
- Oxygen (O): The remaining mass is 18.46 g - 5.89 g - 5.34 g = 7.23 g.
7.23 g / 16.00 g/mol = 0.452 mol
2. Divide each element's mole value by the smallest mole value:
- Potassium: 0.1502 mol / 0.1502 mol = 1 mol
- Chlorine: 0.1505 mol / 0.1502 mol = 1 mol
- Oxygen: 0.452 mol / 0.1502 mol = 3 mol
3. If necessary, round each mole value to the nearest whole number to obtain the simplest whole-number ratio:
- Potassium: 1 mol
- Chlorine: 1 mol
- Oxygen: 3 mol
Therefore, the empirical formula of the compound is KClO3, confirming that the answer you provided is correct.