How many moles of H atoms are there in 21.66 g of Mg(OH)2?
What is the mass of F (in g) in 8.03 x 1023 BF3 molecules
mol Mg(OH)2 = grams/molar mass = 21.66g/molar mass.
There are twice as many mols of H atoms since there are two H atoms/molecule Mg(OH)2.
mols BF3 = 8.63E23/6.02E23 = ?
There are 3x as many F mols.
Then g = mols x atomic mass.
but how do you set them up?
You mean like this? You should be able to take what I first gave you and set it up as below.
21.66 g Mg(OH)2 x [1 mol Mg(OH)2/molar mass Mg(OH)2] x [2 mol H atoms/1 mol Mg(OH)2] =
21.66 x (1/58.32) x (2/1) = mols H atoms.
To determine the number of moles of hydrogen atoms in 21.66 g of Mg(OH)2, you need to use the concept of molar mass and stoichiometry.
Step 1: Calculate the molar mass of Mg(OH)2.
- The molar mass of Mg(OH)2 can be obtained by summing up the atomic masses of all the elements in the compound:
- Mg: 24.31 g/mol
- O: 16.00 g/mol (there are 2 O atoms)
- H: 1.01 g/mol (there are 2 H atoms)
- Molar mass of Mg(OH)2 = 24.31 + (16.00 * 2) + (1.01 * 2) = 58.33 g/mol
Step 2: Convert grams to moles.
- To convert 21.66 g of Mg(OH)2 to moles, divide the given mass by the molar mass:
- Moles of Mg(OH)2 = 21.66 g / 58.33 g/mol ≈ 0.371 mol
Step 3: Determine the moles of hydrogen (H) atoms.
- Since there are 2 moles of H atoms in one mole of Mg(OH)2, multiply the moles of Mg(OH)2 by 2 to get the moles of H:
- Moles of H atoms = 0.371 mol x 2 = 0.742 mol
Therefore, there are approximately 0.742 moles of hydrogen atoms in 21.66 g of Mg(OH)2.
For the second question, to find the mass of fluorine (F) in 8.03 x 10^23 BF3 molecules, you need to use the concept of molar mass and Avogadro's number.
Step 1: Calculate the molar mass of BF3.
- The molar mass of BF3 can be calculated by adding the atomic masses of each element:
- B: 10.81 g/mol
- F: 18.99 g/mol (there are 3 F atoms)
- Molar mass of BF3 = 10.81 + (18.99 * 3) = 10.81 + 56.97 = 67.78 g/mol
Step 2: Calculate the moles of BF3.
- Since 1 mole of a substance contains 6.02 x 10^23 molecules (Avogadro's number), you can use this conversion factor to convert the given number of molecules to moles:
- Moles of BF3 = (8.03 x 10^23 molecules) / (6.02 x 10^23 molecules/mol) ≈ 1.33 mol
Step 3: Determine the mass of fluorine (F).
- Since there are three moles of F atoms in one mole of BF3, multiply the moles of BF3 by 3 to obtain moles of F:
- Moles of F atoms = 1.33 mol x 3 = 3.99 mol
- Finally, calculate the mass of F by multiplying the moles of F by the molar mass of F:
- Mass of F = 3.99 mol x 18.99 g/mol ≈ 75.93 g
Therefore, the mass of fluorine (F) in 8.03 x 10^23 BF3 molecules is approximately 75.93 grams.