What is the molar mass of calcium nitrate, Ca(NO3)2?
A 16 g
B 63 g
C 164 g
D 96 g
E 150.1 g
The Correct Answer and Explanation is :
The correct answer is C) 164 g.
To calculate the molar mass of calcium nitrate, ( \text{Ca(NO}_3)_2 ), we need to sum up the atomic masses of all the elements in the compound.
Step 1: Identify the elements and their atomic masses
- Calcium (Ca): The atomic mass of calcium is approximately 40.08 g/mol.
- Nitrogen (N): The atomic mass of nitrogen is approximately 14.01 g/mol.
- Oxygen (O): The atomic mass of oxygen is approximately 16.00 g/mol.
Step 2: Break down the formula ( \text{Ca(NO}_3)_2 )
The formula ( \text{Ca(NO}_3)_2 ) represents one calcium atom, two nitrogen atoms, and six oxygen atoms. This can be written as:
- 1 calcium (Ca) atom
- 2 nitrogen (N) atoms
- 6 oxygen (O) atoms
Step 3: Calculate the total mass of each element
- Calcium (Ca): There is 1 calcium atom, so the mass contribution from calcium is:
[
1 \times 40.08 \, \text{g/mol} = 40.08 \, \text{g/mol}
] - Nitrogen (N): There are 2 nitrogen atoms, so the mass contribution from nitrogen is:
[
2 \times 14.01 \, \text{g/mol} = 28.02 \, \text{g/mol}
] - Oxygen (O): There are 6 oxygen atoms, so the mass contribution from oxygen is:
[
6 \times 16.00 \, \text{g/mol} = 96.00 \, \text{g/mol}
]
Step 4: Add up the masses
Now, we can sum the individual masses:
[
40.08 \, \text{g/mol} + 28.02 \, \text{g/mol} + 96.00 \, \text{g/mol} = 164.10 \, \text{g/mol}
]
Thus, the molar mass of calcium nitrate is approximately 164 g/mol.
Conclusion:
The correct answer is C) 164 g.