Question

Heating oil, C₁₅H_32, has a high flash point so even a lit match will not burn heating oil in its liquid state. How many moles of heating oil contain 7.05 x 10²⁴ atoms

Answer 1

According to Avogadro's Hypothesis, 1 mole of any substances (Atom/molecule/ions/electrons) contain Avogadro Number i.e. 6.022*10²³ number of particles (Atom/molecule/ions/electrons).

1 mole of Heating Oil C15H32 molecules = 6.022*10²³ Heating oil molecules.

1 Heating molecule C15H32 = 15 C atoms + 32 H atoms = 47 atoms.

1 mole of Heating Oil C15H32 molecules = 47 * 6.022*10²³ Atoms = 2.83*10²⁵ Atoms.

Now as per question and above calculations we write,

If, 1 mole of Heating Oil C15H32 molecules = 2.83*10²⁵ Atoms.

then say N mole of Heating Oil C15H32 molecules = 7.05*10²⁴ Atoms.

On cross multiplication,

N * 2.83*10²⁵ Atoms = 1 mol * 7.05*10²⁴ Atoms.

N = 7.05*10²⁴ Atoms / 2.83*10²⁵ Atoms *1 mole

N = 0.249 mol

0.249 mole of Heating oil C15H32 will have  7.05*10²⁴ Atoms.

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