Set the formula for saturated hydrocarbon, the mass fraction of carbon in which is 0.8276?

Given:
Saturated Hydrocarbon – CnH2n + 2
ω (C in CnH2n + 2) = 0.8276

To find:
CnH2n + 2 -?

Decision:
1) Calculate the relative molecular weight of CnH2n + 2:
Mr (CnH2n + 2) = N (C in CnH2n + 2) * Ar (C) * 100% / ω (C in CnH2n + 2) = n * 12 / 0.8276 = 12n / 0.8276;
2) Calculate the relative molecular weight of CnH2n + 2:
Mr (CnH2n + 2) = Ar (C) * N (C) + Ar (H) * N (H) = 12 * n + 1 * (2n + 2) = 14n + 2;
3) Solve the equation:
12n / 0.8276 = 14n + 2;
12n = 11.5864n + 1.6552;
0.4136n = 1.6552;
n = 4;
4) The formula of the saturated hydrocarbon is C4H10 – butane.

Answer: The formula for saturated hydrocarbon is C4H10 – butane.