Question

unit 2 - lcc 3 hw - mole conversions
1 mol = 6.02 x 10^23 atoms
(1 mole / 6.02x10^23 atoms) or (6.02x10^23 atoms / 1 mole)
mole - atom conversions

1. how many moles are 2.55 x 10^27 atoms of zinc (zn)?
2. how many atoms are in 30.0 moles of calcium (ca)?
3. how many atoms are in 0.45 moles of carbon (c)?
4. how many moles are 7.8 x 10^24 atoms of helium?

1 mol = grams (molar mass) (get this from the periodic table) (1 mole / g) or (g / 1 mole)
mole - mass conversions

1. how many moles in 38.0 grams of oxygen?
2. what is the mass of 6.0 moles of iron?
3. find the number of moles of argon in 472 g of argon.
4. find the grams in 14.5 mol of hydrogen.

Explanation:

Mole - Atom Conversions

1.

Step1: Use Avogadro's number conversion

We know that 1 mole = $6.02\times10^{23}$ atoms. To find moles from atoms, we divide the number of atoms by Avogadro's number.
$n=\frac{2.55\times 10^{27}\text{ atoms}}{6.02\times 10^{23}\text{ atoms/mol}}$

Step2: Calculate the result

$n = 4236\text{ mol}$

Step1: Use Avogadro's number conversion

Since 1 mole = $6.02\times10^{23}$ atoms, to find the number of atoms from moles, we multiply the number of moles by Avogadro's number.
$N=30.0\text{ mol}\times6.02\times 10^{23}\text{ atoms/mol}$

Step2: Calculate the result

$N = 1.806\times 10^{25}\text{ atoms}$

Step1: Use Avogadro's number conversion

Multiply the number of moles by Avogadro's number to get the number of atoms.
$N = 0.45\text{ mol}\times6.02\times 10^{23}\text{ atoms/mol}$

Step2: Calculate the result

$N=2.709\times 10^{23}\text{ atoms}$

Answer:

4236 mol

2.