Question

How many carbon atoms are in 1.50 g of butane?

Answer 1

Formula weight for butane is 12x4+10 = 58 g/mol

C=48/58 mol = 83% of butane is carbon, so .83(1.5g) = 1.245 grams C

now convert to atoms

1.245g C (6.022x10^23/12g) = atoms C

Answer 2

Answer: Number of carbon atoms in butane are $6.022 \times 10^{23}$.

Explanation:

Butane is $CH_{3}CH_{2}CH_{2}CH_{3}$.

The molecular mass of butane is $12 \times 4 + 10$

                             = 48 + 10 = 58 g/mol

Percentage of carbon in 1 mole of butane molecule = $\frac{48}{58} \times 100$

                                                                      = $82.75\%$

The mass of carbon in 1.5 g of butane is as follows.

                          $\frac{82.75}{100} \times 1.5$

                            = 1.24 g

Number of moles of carbon = $\frac {mass available}{molar mass of carbon}$

                                            = $\frac{1.24}{12}$

                                           = 0.103 mol

Number of carbon atoms in butane = $6.022 \times 10^{23} \times 0.103$

                                                          = $6.022 \times 10^{23}$

Therefore, there are $6.022 \times 10^{23}$ atoms of carbon in butane.