a) How many CaH2 formula units are present
in 7.657 g of CaH2?
Answer in units of formula units.
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.
To determine the number of CaH2 formula units present in 7.657 g, we need to use the molar mass of CaH2 to convert the grams to moles, and then use Avogadro's number to convert moles to formula units.
The molar mass of CaH2 can be calculated as follows:
Ca: 40.08 g/mol
H: 1.01 g/mol
Molar mass of CaH2 = (Ca: 40.08 g/mol) + 2*(H: 1.01 g/mol) = 42.10 g/mol
Now, we can calculate the number of moles of CaH2 in 7.657 g by dividing the mass by the molar mass:
Number of moles = mass / molar mass = 7.657 g / 42.10 g/mol
Now, we can convert moles to formula units using Avogadro's number, which is 6.022 x 10^23 formula units per mole:
Number of formula units = number of moles x Avogadro's number
Now, let's calculate:
Number of moles = 7.657 g / 42.10 g/mol = 0.182 moles
Number of formula units = 0.182 moles x (6.022 x 10^23 formula units/mol)
Therefore, there are approximately 1.097 x 10^23 CaH2 formula units present in 7.657 g of CaH2.
To find the number of CaH2 formula units present in 7.657 g of CaH2, we need to use the concept of molar mass and Avogadro's number.
Step 1: Find the molar mass of CaH2.
The molar mass of CaH2 can be calculated by adding the atomic masses of calcium (Ca) and hydrogen (H).
The atomic mass of Ca = 40.08 g/mol
The atomic mass of H = 1.008 g/mol
So, the molar mass of CaH2 = (40.08 g/mol) + 2 * (1.008 g/mol) = 42.096 g/mol
Step 2: Convert grams to moles.
Using the molar mass, we can convert grams of CaH2 to moles:
Number of moles = Mass (g) / Molar mass
Number of moles = 7.657 g / 42.096 g/mol = 0.182 mol
Step 3: Use Avogadro's number to convert moles to formula units.
Avogadro's number represents the number of particles (atoms, molecules, or formula units) in one mole of a substance. Avogadro's number is approximately 6.022 x 10^23 formula units/mol.
Number of formula units = Number of moles * Avogadro's number
Number of formula units = 0.182 mol * (6.022 x 10^23 formula units/mol) = 1.095 x 10^23 formula units
Therefore, there are approximately 1.095 x 10^23 CaH2 formula units present in 7.657 g of CaH2.