Question

Calcium carbonate reacts with nitric acid to produce calcium nitrate. Calculate the relative formula mass of calcium nitrate, Ca(NO3)2.

a) 148 g/mol
b) 164 g/mol
c) 108 g/mol
d) 120 g/mol

Answer 1

The relative formula mass of calcium nitrate, Ca(NO3)2, is calculated by summing the masses of calcium, nitrogen, and oxygen atoms in the formula, resulting in a total molar mass of 164.10 g/mol. The correct answer is 164 g/mol.

Step-by-step explanation:

The relative formula mass (molar mass) of calcium nitrate, Ca(NO3)2, can be calculated by summing the masses of all the atoms in the formula.

First, we identify the number of atoms in the formula:

• Calcium (Ca): 1 atom
• Nitrogen (N): 2 atoms
• Oxygen (O): 6 atoms (because of the 2 nitrate ions, each having 3 oxygen atoms)

Next, we calculate the molar masses of individual elements and multiply by their numbers in the compound:

Calcium: 1 x 40.08 g/mol = 40.08 g/mol

Nitrogen: 2 x 14.01 g/mol = 28.02 g/mol

Oxygen: 6 x 16.00 g/mol = 96.00 g/mol

The total molar mass of calcium nitrate is the sum of all these:

40.08 g/mol (Calcium) + 28.02 g/mol (Nitrogen) + 96.00 g/mol (Oxygen) = 164.10 g/mol

Therefore, the correct answer is 164 g/mol (option b).