Question

A compound contains 75% carbon and 25%hydrogen by mass. What is the empirical formulafor this compound?CHCHCH2 18DONE

Answer 1

Hello!

A compound contains 75% carbon and 25% hydrogen by mass. What is the empirical formula for this compound ?

data:

Carbon (C) ≈ 12 a.m.u (g/mol)

Hydrogen (H) ≈ 1 a.m.u (g/mol)

We use the amount in grams (mass ratio) based on the composition of the elements, see: (in 100g solution)

C: 75 % = 75 g

H: 25 % = 25 g

The values ​​(in g) will be converted into quantity of substance (number of mols), dividing by molecular weight (g / mol) each of the values, we will see:

`C: (75\:\diagup\!\!\!\!\!g)/(12\:\diagup\!\!\!\!\!g/mol) = 6.25\:mol`

`H: (25\:\diagup\!\!\!\!\!g)/(1\:\diagup\!\!\!\!\!g/mol) = 25\:mol`

We realize that the values ​​found above are not integers, so we divide these values ​​by the smallest of them, so that the proportion does not change, let us see:

`C: (6.25)/(6.25)\to\:\:\boxed{C = 1}`

`H: (25)/(6.25)\to\:\:\boxed{H = 4}`

Thus, the minimum or empirical formula found for the compound will be:

`\boxed{\boxed{C_1H_4\:\:\:or\:\:\:CH_4}}\Longleftarrow(Empirical\:Formula)\end{array}}\qquad\checkmark`

Answer:

CH4 (Methane)

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I Hope this helps, greetings ... Dexteright02! =)

Answer 2

To get the empirical formula of the compound, we convert each mass percentage to mole percentage by dividing each to corresponding molar mass. 75% mass of carbon is 6.25 while 25% hydrogen is 25. We divide 25 by 6.25, we get 4. Hence, the empirical formula is CH4.