How many atoms of iron are in 0.750 moles of the compound
iron(iii) oxide?

2.26 × 10²⁴ atoms

Explanation:

In 1 mole of Fe₂O₃ (Iron(III) oxide), there are 6.02 × 10²³ molecules of Fe₂O₃ (Avogadro's number). The molecules of Fe₂O₃ in 0.750 moles are:

0.750 mol × (6.02 × 10²³ molecules/ 1 mol) = 4.52 × 10²³ molecules

In 1 molecule of Fe₂O₃, there are 5 atoms (2 atoms of Fe and 3 atoms of O). The atoms in 4.52 × 10²³ molecules of Fe₂O₃ are:

4.52 × 10²³ molecule × (5 atom/1 molecule) = 2.26 × 10²⁴ atom

There are 2.26 × 10²⁴ atoms in 0.750 moles of Fe₂O₃.

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante