To calculate the number of CaH2 formula units, we need to determine the molar mass of CaH2, which is the sum of the atomic masses of calcium (Ca) and hydrogen (H).
The atomic mass of calcium (Ca) is 40.08 g/mol, and the atomic mass of hydrogen (H) is 1.01 g/mol.
The molar mass of CaH2 is 40.08 g/mol + 2(1.01 g/mol) = 42.10 g/mol.
To find the number of moles in 7.657 g of CaH2, we divide the mass by the molar mass:
Number of moles = 7.657 g / 42.10 g/mol ≈ 0.1820 mol
Since 1 mol of CaH2 is equal to 6.022 x 10^23 formula units (Avogadro's number), we can calculate the number of CaH2 formula units as:
Number of formula units = 0.1820 mol x 6.022 x 10^23 formula units/mol ≈ 1.1 x 10^23 formula units
Therefore, there are approximately 1.1 x 10^23 CaH2 formula units present in 7.657 g of CaH2.
a) How many CaH2 formula units are present
in 7.657 g of CaH2?
Answer in units of formula units.
1 answer