Question

how many atoms are in 165 g of calcium? 165 g = atoms

Explanation:

Step1: Determine molar mass of calcium

The molar mass of calcium (Ca) is approximately 40.08 g/mol.

Step2: Calculate number of moles

The number of moles $n$ is calculated by the formula $n=\frac{m}{M}$, where $m = 165$ g is the mass and $M=40.08$ g/mol is the molar mass. So $n=\frac{165}{40.08}\approx4.12$ mol.

Step3: Use Avogadro's number

Avogadro's number $N_A = 6.022\times10^{23}$ atoms/mol. The number of atoms $N$ is given by $N=n\times N_A$. So $N = 4.12\times6.022\times10^{23}\approx2.48\times 10^{24}$ atoms.

Answer:

$2.48\times 10^{24}$