Question

The chemical formula of propane is C3H8. Which number correctly uses scientific notation to represent the number of atoms in 2.00 moles of propane?

Answer 1

1.2046*10²⁴ atoms

Step-by-step explanation:

Avogadro's Number or Avogadro's Constant to the number of particles that constitute a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023 * 10²³ particles per mole. Avogadro's number represents a quantity without an associated physical dimension, so it is considered a pure number that allows describing a physical characteristic without dimension or explicit unit of expression. The Avogadro number applies to any substance.

Then a rule of three applies as follows: if 1 mole has 6,023 * 10²³ atoms, 2 moles how many atoms will it contain?

`number of atoms=(2 moles*6.023*10^(23) )/(1mole)`

number of atoms=1.2046*10²⁴ atoms

This number is already represented in scientific notation.

Answer 2

Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles. We do as follows:

2.00 mol C3H8 ( 6.022 x 10^23 atoms / mole ) = 1.204x10^24 atoms C3H8