Question

calculate the number of molecules present in 100 grams for both water and carbon dioxide (3.34×10^24 and 1.37×10^24).

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Answer 1

For H2O:

Molar mass of H2O is 18 grams per mole.

So, 100 grams is 100/18 => 50/9 mol

1 mol has 6.023*10^23 molecules.

So, 50/9 moles will have 50/9 * 6.023*10^23 molecules.

=> 33.4 * 10^23 molecules.

For CO2:

Molar mass of CO2 is 44 grams per mole.

So, 100 grams of CO2 contains, 100/44 => 25/11 moles

Each mole has 6.023 * 10^23 molecules.

So, 25/11*6.023 *10^23 molecules are present.

=>13.69 * 10^23 molecules

=> 13.7 * 10^23 molecules of CO2 approximately.