[tex] \LARGE{ \boxed{ \rm{ \purple{Required \: answer}}}}[/tex]
☃️ Chemical formulae ➝ [tex]\sf{CaCO_3}[/tex]
How to find?
For solving this question, We need to know how to find moles of solution or any substance if a certain weight is given.
[tex] \boxed{ \sf{No. \: of \: moles = \frac{given \: weight}{molecular \: weight} }}[/tex]
And, Then we need to find the number of molecules which can be found by:
[tex] \large{ \boxed{ \sf{no. \: of \: molecules = N_A \times no. \: of \: moles}}}[/tex]
Here, Na = Avagadro Number (6.022 × 10²³)
☀️ As it is a compund, We considered molecules. Then, we can predict the no. of atoms of elements in one molecule of compound and get the answer.
Solution:
Atomic weight of elements:
❍ Molecular weight of [tex]\sf{CaCO_3}[/tex]
= 40 + 12 + 3 × 16
= 52 + 48
= 100 g/mol
❍ Given weight: 10 g
Then, no. of moles,
⇛ No. of moles = 10 g / 100 g mol‐¹
⇛ No. of moles = 0.1 moles
☄ No. of moles of Calcium carbonate in the given weight = 0.1 moles
Finding no. of molecules,
⇛ No. of molecules of CaCO3 = 0.1 × 6.022 × 10²³
⇛ No. of molecules of CaCO3 = 6.022 × 10²²
Now,
- 1 molecule of [tex]\sf{CaCO_3}[/tex] = 3 atoms of Oxygen.
Then, 6.022 × 10²² molecules will have,
= 3 × 6.022 × 10²² atoms of oxygen
= 18.022 × 10²² atoms of oxygen
In more scientific form,
= 1.8022 × 10²³ atoms of oxygen
☄ Hence, Final answer - 1.8022 × 10²³ atoms
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