(sample g/1) X (1 mole/40.078(MW of Ca)) = moles of sample (moles of sample)(6.022 x 10^23( no of atoms)/ 1 mole) = # of atoms in a 120 g sample of calcium Avogadro's number=6.022x 10^23 atoms in 1 mole
<span>1. Blocks Ultra violet rays that can be harmful.
2. Provides Oxygen, so we can live.
3. It blocks meteors from hitting Earth's surface.
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Particles as small as atoms exist.
