Empirical formula problem?

What do you do when the mass of the element is greater than the percent it takes up in the compound?

What is the empirical formula of a compound that is 34.6% Gallium, 17.8% Carbon, & 47.6% Oxygen?

How do I figure out how many moles Gallium has!?

Atomic mass of Gallium = 69.723

Comments

  • The total percentage of the elements represents 100% of the compound. Now, assume that each element mentioned represents that many grams.

    mass Ga = 34.6 g

    mass C = 17.8 g

    mass O = 47.6 g

    Now, calculate the moles of each element.

    moles Ga = 34.6 g(1 mole)/(69.723 g) = 0.4962 moles Ga

    moles C = 17.8 g(1 mole)/(12.011 g) = 1.482 moles C

    moles O = 47.6 g(1 mole)/(15.999 g) = 2.975 moles O

    Now, divide each of the moles by the smallest amount to obtain the relative number of each atom in the compound.

    Ga (0.4962 )/(0.4962 ) = 1.00 = 1 atom

    C (1.482)/(0.4962) = 2.987 = 3 atoms

    O (2.975)/(0.4962) = 5.996 = 6 atoms

    Empirical formula = GaC3O6

    Hope this is helpful to you. JIL HIR

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