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Questions
Determine the empirical formula of a compound containing 47.9‰ K, 5.5‰ beryllium and 46.6‰ fluorine by mass.
Determine the empirical formula of a compound containing 47.9% potassium, 5.5% beryllium and 46.6% fluorine by mass. (Atomic weight of Be = 9; F = 19; K = 39). Work to one decimal place.
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Solution
| Element | Atomic mass | Percentage | Relative Number of moles | Simplest mole ratio | Whole number ratio |
| K | 39 | 47.9 | `47.9/39` = 1.2 | `1.2/0.6` = 2 | 2 |
| Be | 9 | 5.5 | `5.5/9` = 0.6 | `0.6/0.6` = 1 | 1 |
| F | 19 | 46.6 | `46.6/19` = 2.4 | `2.4/0.6` = 4 | 4 |
The empirical formula of compound = K2BeF4.
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