Question

What would be the mass, in grams, of 2.408 x 1024 molecules of tetraphosphorus decaoxide?

Answer 1

Answer:

1,135 grams P₄O₁₀

Explanation:

To find the mass, you need to (1) convert molecules to moles (via Avogadro's Number) and then (2) convert moles to grams (via molar mass from periodic table values). It is important to arrange the ratios/ conversions in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 4 sig figs to reflect the given value (2.408 x 10²⁴).

Avogadro's Number:

1 mole = 6.022 x 10²³ molecules

tetraphosphorus decaoxide = P₄O₁₀

Molar Mass (P₄O₁₀): 4(30.974 g/mol) + 10(15.998 g/mol)

Molar Mass (P₄O₁₀): 283.876 g/mol

2.408 x 10²⁴ molecules P₄O₁₀                     1 mole                         283.876 g
-------------------------------------------  x  ------------------------------------  x  -----------------
                                                         6.022 x 10²³ molecules           1 mole

=  1,135 grams P₄O₁₀