Question

How many molecules of butane (C4H10) are contained in a 9.213 g sample? How many hydrogen atoms are contained in this

Answer 1

9.03 X $10^{22}$ molecules of butane is present in 9.213 grams of the sample.

1.5 atoms of hydrogen are present in the sample 9.123 grams of butane.

Explanation:

Data given:

mass of butane  C4H10= 9.123 grams

atomic mass of butane = 58.12 grams/mole

number of molecules =?

number of hydrogen atoms in the sample=?

number of moles is calculated as :

number of moles = $\frac{mass}{atomic mass of 1 mole}$

putting the values in the above equation:

number of moles of butane = $\frac{9.213}{58.12}$

                                             = 0.15 moles

number of molecules = number of moles x 6.02 x $10^{23}$ (Avagadro number)

Putting the values in above formula:

number of molecules of Butane = 0.15 X 6.023 X $10^{23}$

                                                       = 9.03 X $10^{22}$ molecules

Number of hydrogen atoms:

1 mole of C4H10 contains 10 atoms of H

0.15 moles of C4H10 will have x moles

$\frac{10}{1}$ = $\frac{x}{0.15}$

x = 0.15 atoms of hydrogen