Question #c8eb4

1 Answer
Mar 12, 2017

Answer:

The formula is #K_2O#

Explanation:

To do empirical formula problems, follow these steps:

  1. Convert the masses given into moles, by dividing each mass by the molar mass of that substance:

moles K = #(32.9 g)/(39.1 g/"mol") = 0.8414 " mol"#

moles O = #(6.73 g)/(16.0 g/"mol") = 0.4206 " mol"#

  1. Next find a simple whole-number ratio between these mole amounts. It usually helps to divide both numbers by the smaller.

K: #0.8414 / 0.4206 = 2.00#

O: #0.4206 /0.4206 = 1.00#

  1. Use the ratio find in step 2 to write a formula. In this case, we now know there are 2 moles of K for each 1 mole of O:

Empirical formula = #K_2O#