Answer:
42.1737 g
Step-by-step explanation:
To calculate the mass of 0.257 moles of Ca(NO3)2, we first need to determine the molar mass of Ca(NO3)2. The molar mass of a substance is the mass of one mole of that substance. The molar mass of Ca(NO3)2 can be calculated by adding the atomic masses of each atom in the molecule. The atomic masses of calcium, nitrogen, and oxygen are 40.08 g/mol, 14.01 g/mol, and 16.00 g/mol, respectively. Therefore, the molar mass of Ca(NO3)2 is 40.08 g/mol + 2(14.01 g/mol) + 6(16.00 g/mol) = 164.10 g/mol.
Once we know the molar mass of Ca(NO3)2, we can calculate the mass of 0.257 moles of Ca(NO3)2 using the following formula:
mass = moles × molar mass
Substituting the values we know, we get:
mass = 0.257 moles × 164.10 g/mol = 42.1737 g
Therefore, the mass of 0.257 moles of Ca(NO3)2 is 42.1737 g.