ANSWER
The number of particles of calcium is 3.79 x 10^23 particles
STEP-BY-STEP EXPLANATION
Given information
The mole of calcium = 0.630 moles
Let x represents the number of particles
The next step is to find the number of particles using the below formula
[tex]\text{Number of moles = }\frac{\text{ }Number\text{ of particles}}{\text{Avogadro's number}}[/tex]Recall that, Avogadro's number is 6.022 x 10^23
[tex]\begin{gathered} 0.630\text{ = }\frac{x}{6.022\times10^{23}} \\ \text{cross multiply} \\ x\text{ = 0.630 }\times\text{ 6.022}\times10^{23} \\ x\text{ = 0.630 }\times\text{ 6.022 }\times10^{23} \\ x\text{ = 3.79 }\times10^{23}\text{particles} \end{gathered}[/tex]
Therefore, the number of particles of calcium is 3.79 x 10^23 particles