Question

use the mole quick check
the atomic mass of the element platinum (pt) is 195.08 amu. how many atoms of platinum are in 195.08 grams? (1 point)
1.175 × 10²⁶ atoms
6.022 × 10²³ atoms
1.951 × 10²⁵ atoms
3.087 × 10²¹ atoms

Explanation:

Step1: Calculate the number of moles of platinum

The atomic mass of platinum \(Pt\) is \(195.08\) amu. By definition, the molar mass \(M\) of an element (in \(g/mol\)) has the same numerical value as its atomic mass (in amu). So, for platinum, \(M = 195.08\space g/mol\).
The formula to calculate the number of moles \(n\) is \(n=\frac{m}{M}\), where \(m = 195.08\space g\) (given mass) and \(M=195.08\space g/mol\).

$$n=\frac{195.08\space g}{195.08\space g/mol}= 1\space mol$$

Step2: Calculate the number of atoms using Avogadro's number

Avogadro's number \(N_A=6.022\times 10^{23}\space atoms/mol\).
The formula to calculate the number of atoms \(N\) is \(N = n\times N_A\).
Since \(n = 1\space mol\), then \(N=1\space mol\times6.022\times 10^{23}\space atoms/mol\)

Answer:

\(6.022\times 10^{23}\space atoms\) (the second option)