What is the percent by mass of chlorine in Ca(ClO3)2?
The Correct Answer and Explanation is:
To find the percent by mass of chlorine in calcium chlorate (Ca(ClO3)2), we first need to determine the molecular mass of Ca(ClO3)2 and the total mass of chlorine in the compound.
Step 1: Calculate the molar mass of Ca(ClO3)2
We break down the compound into its individual elements:
- Calcium (Ca): The atomic mass of calcium is 40.08 g/mol.
- Chlorine (Cl): The atomic mass of chlorine is 35.45 g/mol. There are two chlorine atoms in the formula.
- Oxygen (O): The atomic mass of oxygen is 16.00 g/mol. Since there are six oxygen atoms (because of the subscript 3 in ClO3 and the subscript 2 for the entire chlorine group), the total mass of oxygen is 6 × 16.00 = 96.00 g/mol.
Now we calculate the molar mass of Ca(ClO3)2:Molar mass of Ca(ClO3)2=40.08+(2×35.45)+(6×16.00)\text{Molar mass of Ca(ClO3)2} = 40.08 + (2 \times 35.45) + (6 \times 16.00)Molar mass of Ca(ClO3)2=40.08+(2×35.45)+(6×16.00)=40.08+70.90+96.00=206.98 g/mol= 40.08 + 70.90 + 96.00 = 206.98 \, \text{g/mol}=40.08+70.90+96.00=206.98g/mol
Step 2: Calculate the total mass of chlorine in the compound
There are two chlorine atoms in one formula unit of Ca(ClO3)2. Therefore, the total mass of chlorine is:Mass of chlorine=2×35.45=70.90 g/mol\text{Mass of chlorine} = 2 \times 35.45 = 70.90 \, \text{g/mol}Mass of chlorine=2×35.45=70.90g/mol
Step 3: Calculate the percent by mass of chlorine
The percent by mass of chlorine is the ratio of the mass of chlorine to the total molar mass of the compound, multiplied by 100:Percent by mass of chlorine=(70.90206.98)×100=34.2%\text{Percent by mass of chlorine} = \left( \frac{70.90}{206.98} \right) \times 100 = 34.2\%Percent by mass of chlorine=(206.9870.90)×100=34.2%
Conclusion:
The percent by mass of chlorine in Ca(ClO3)2 is 34.2%. This means that in any given sample of calcium chlorate, 34.2% of its mass comes from chlorine.
