Calculate the number of moles and number of molecules present in 16g H2CO3

The molar mass of H2CO3 (carbonic acid) is 62.03 g/mol.

To calculate the number of moles, we use the formula:
Number of moles = Mass / Molar mass

Number of moles = 16g / 62.03 g/mol
Number of moles = 0.258 mol

Now, to calculate the number of molecules, we use Avogadro's number which is 6.022 x 10^23 molecules/mol.

Number of molecules = Number of moles * Avogadro's number
Number of molecules = 0.258 mol * 6.022 x 10^23 molecules/mol
Number of molecules = 1.554 x 10^23 molecules

Therefore, there are 0.258 moles and approximately 1.554 x 10^23 molecules present in 16g of H2CO3.