Chemistry
Grade-9
Easy
Question
Which of the following will contain the same number of atoms as 20g of calcium?
- 8gm of O2
- 28gm of Al
- 24gm of Mg
- 12gm of C
Hint:
Equal number of moles of any element has equal number of atoms.
The correct answer is: 8gm of O2
Atomic mass of Calcium is 40 g. Number of moles of calcium in 20g 0.5 mole.
Equal number of moles of any element has equal number of atoms.
Atomic number of oxygen is 16g, 8g of oxygen is 0. moles.
Therefore, 8g of oxygen contain the same number of atoms as 20g of calcium.
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