Question

Calculate the number of hydrogen atoms in a 110.0 sample of tetraborane(B4H10) . Be sure your answer has a unit symbol if necessary, and round it to 4 significant digits.

Answer 1

Answer:

$1.242 \times 10^{25}\text{ atoms H}$

Explanation:

You must convert the mass of B₄H₁₀ to moles of B₄H₁₀, then to molecules of B₄H₁₀, and finally to atoms of H.

1. Moles of B₄H₁₀

$\text{Moles of B _{4} H}_{10} = \text{110.0 g B _{4} H}_{10} \times \dfrac{\text{1 mol B _{4} H}_{10}}{\text{53.32 g B _{4} H}_{10}} = \text{2.063 mol B _{4} H}_{10}$

2. Molecules of B₄H₁₀

$\text{No. of molecules} = \text{2.063 mol B _{4} H}_{10} \times \dfrac{6.022 \times 10^{23}\text{ molecules B _{4} H}_{10}}{\text{1 mol B _{4} H}_{10}}\\\\=1.242 \times 10^{24}\text{ molecules B _{4} H}_{10}$

3. Atoms of H

$\text{Atoms of H} = 1.242 \times 10^{24}\text{ molecules B _{4} H}_{10} \times \dfrac{\text{10 atoms H}}{\text{1 molecule B _{4} H}_{10}}\\\\= \mathbf{1.242 \times 10^{25}}\textbf{ atoms H}$