Question

How many atoms are in each elemental sample?

16.8 g Sr
26.5 g Fe
8.94 g Bi
40.0 g P

Answer 1

To find the number of atoms, first we calculate the moles of the element by dividing its mass by its atomic mass. Then, we multiply the moles by Avogadro's number to obtain the atom count. This process is applied to Sr, Fe, Bi, and P with their respective atomic masses to yield the answer.

Step-by-step explanation:

To determine how many atoms are in each elemental sample, we first calculate the number of moles of the element. The number of moles is calculated by dividing the mass of the sample by the atomic mass of the element, which can be found on the periodic table. After finding the number of moles, we multiply it by Avogadro's number, which is 6.022 × 1023 atoms per mole, to find the total number of atoms.

For Strontium (Sr), the atomic mass is 87.62 g/mol:
16.8 g Sr ÷ 87.62 g/mol = 0.1918 mol Sr
0.1918 mol Sr × 6.022 × 1023 atoms/mol = 1.155 × 1023 atoms Sr

For Iron (Fe), the atomic mass is 55.845 g/mol:
26.5 g Fe ÷ 55.845 g/mol = 0.4747 mol Fe
0.4747 mol Fe × 6.022 × 1023 atoms/mol = 2.857 × 1023 atoms Fe

For Bismuth (Bi), the atomic mass is 208.9804 g/mol:
8.94 g Bi ÷ 208.9804 g/mol = 0.0428 mol Bi
0.0428 mol Bi × 6.022 × 1023 atoms/mol = 2.578 × 1022 atoms Bi

For Phosphorus (P), the atomic mass is 30.974 g/mol:
40.0 g P ÷ 30.974 g/mol = 1.291 mol P
1.291 mol P × 6.022 × 1023 atoms/mol = 7.776 × 1023 atoms P

Answer 2

Step-by-step explanation:

The number of atoms in 1mol of every element can be represented by Avogadro's number, which is
`6.022*10^(23)`.

Knowing this, now we can find the atoms in each of these molecules!

`16.8gSr*(1molSr)/(87.62gSr) *(6.022*10^(23)atomsSr)/(1molSr) =`

1.15*10^23 atoms of Sr

`26.5gFe*(1molFe)/(55.85gFe) *(6.022*10^(23)atomsFe)/(1molFe) =`

2.86*10^23 atoms of Fe

`8.94gBi*(1molBi)/(208.98gBi) *(6.022*10^(23)atomsBi)/(1molBi) =`

2.58*10^22 atoms of Bi

`40.0gP*(1molP)/(30.97gP) *(6.022*10^(23)atomsP)/(1molP)=`

7.78*10^23 atoms of P