# How to find the formula of this alkane? [closed]

It says that the mass of Carbon and Hydrogen are 8:45. We are talking about an alkane here. General formula is CnH2n+2. What is the particular formula?

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## closed as off topic by ManishEarth♦Jan 24 '13 at 7:44

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Could you be a bit clearer here? I'll reopen when you elaborate/clarify your question and show what you have tried. – ManishEarth Jan 24 '13 at 7:44

$$12n/(2n+2) = 45/8$$
This follows naturally from the general formula for alkanes. Solving the equation, we find $n = 15$, yielding the chemical formula C15H32.