1.75 x 10^25 selenium atoms contains how many moles of selenium?
1 mol contains 6.02E23 atoms.
I am still not understanding.
Set up a proportion if you don't understand it any other way. For example, you have 5 oranges. They weigh 8 lbs. How much does one weigh?
(8 lbs/5 oranges) = (?lb/1 orange)
Solve for ? = 8*(1/5) = 1.6 lb each.
(1.75E25 atoms/?mol) = (6.02E23 atoms/1 mol).
? mol = 1.75E23 x (1/6.02E23) = ?
Any problem that is directly proportional can be done this way. Another way is to use dimensional analysis.
You know 1 mol contains 6.02E23 atoms. You want to know how many mols in 1.l75E25 atoms.
1.75E25 x conversion factor to convert atoms to mols.
1.75E23 atoms x (1 mol/6.02E23 atoms = ?
Note that atoms in the numerator cancel with atoms in the denominator and leaves mols (w3hich is what you wanted). Dimensional analysis always works.
To find the number of moles of selenium in 1.75 x 10^25 selenium atoms, we need to use Avogadro's number and the molar mass of selenium.
Avogadro's number (represented as "NA") is the number of atoms or molecules in one mole of a substance, which is approximately 6.022 x 10^23 particles per mole.
The molar mass of selenium (denoted by "M") is the mass of one mole of selenium atoms, which is 78.96 grams/mol.
To calculate the number of moles of selenium, we can follow these steps:
1. Convert the given number of selenium atoms into moles by dividing it by Avogadro's number:
Number of moles = (Number of atoms) / (Avogadro's number)
Number of moles = (1.75 x 10^25) / (6.022 x 10^23)
2. Multiply the number of moles by the molar mass of selenium to get the mass in grams:
Mass of selenium = (Number of moles) x (Molar mass of selenium)
Mass of selenium = (Number of moles) x (78.96 g/mol)
Therefore, to find the number of moles of selenium in 1.75 x 10^25 selenium atoms, you can use the above calculations to calculate the answer.