Answer:
1.11 x 10²³ atoms O
Step-by-step explanation:
To find the number of oxygen atoms in FeSO₄, you need to (1) convert FeSO₄ from grams to moles (using the molar mass), then (2) convert moles FeSO₄ to moles O (using the mole-to-mole ratio of FeSO₄), and then (3) convert moles O to atoms O (using Avogadro's Number). It is important to arrange the conversions/ratios in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 3 sig figs like the given number (7.00 = 3 sig figs).
Atomic Mass (Fe): 55.845 g/mol
Atomic Mass (S): 32.065 g/mol
Atomic Mass (O): 15.999 g/mol
Molar Mass (FeSO₄): 55.845 g/mol + 32.065 g/mol + 4(15.999 g/mol)
Molar Mass (FeSO₄): 151.906 g/mol
1 mole FeSO₄: 1 mole Fe, 2 mole S, 4 moles O
Avogadro's Number:
6.022 x 10²³ atoms = 1 mole
7.00 g FeSO₄ 1 mole 4 moles O 6.022 x 10²³ atoms
----------------------- x ------------------- x ----------------------- x ----------------------------
151.906 g 1 mole FeSO₄ 1 mole
= 1.11 x 10²³ atoms O