Question

Define 1 mole.
Calculate the number of moles present in 80 grams of Oxygen.

Answer 1

Define 1 mole.

One mole can be defined as the amount of substance that contain as many elementary entities, such as atoms, molecules, ions, electrons, radicals, etc. as there are atoms in 12 grams of carbon-12.

1 mole = 6.022 x 1023 particles.

Calculate the number of moles present in 80 grams of Oxygen.

Given mass of O2 = 80 g

Molecular mass of O2 = 16 * 2

= 32

No. of moles in O2 = Given mass / Molecular mass

= 80 / 32

= 2.5 moles Ans.

Answer 2

Hii deepika....
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The amount of an element or compound which contain 6.022×10^23atoms or molecules means mass of an element which contains 6.022×10^23 atoms is known as 1 mole of that element..
Means. 1 MOLE=6.022×10^23 atoms
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we know that molar mass of oxygen gas[O2] is 16×2=32g so
the number of moles= given amount of element÷molar mass of that element...

no. of moles in 80g of oxygen=80/32
=2.5 moles
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thank you.