Measurements show that unknown compound x has the following composition:
element mass %
carbon 62.4
hydrogen 4.19
oxygen 33.2
write the empirical chemical formula of x?

The empirical formula of X is .

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C = 62.4 g

Mass of H = 4.19 g

Mass of O = 33.2 g

Step 1 : convert given masses into moles.

Moles of C=

Moles of H=

Moles of O =

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C =

For H =

For O =

The ratio of C: H: O = 2.5 : 2 : 1

Converting it into simple whole number ratios by multiplying by 2:

Hence the empirical formula of X is .

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

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