# Draw up the structural formula of the aldehyde, in which the mass fractions

Draw up the structural formula of the aldehyde, in which the mass fractions of carbon are 54.55%, hydrogen – 9.09%, oxygen – 36.36%. Name the substance found.

Given:
CxHyOz
ω (C) = 54.55%
ω (H) = 9.09%
ω (O) = 36.36%

Find:
CxHyOz -?

Solution:
1) Let m (CxHyOz) = 100 g;
2) m (C) = ω (C) * m (CxHyOz) / 100% = 54.55% * 100/100% = 54.55%;
3) n (C) = m (C) / M (C) = 54.55 / 12 = 4.546 mol;
4) m (H) = ω (H) * m (CxHyOz) / 100% = 9.09% * 100/100% = 9.09%;
5) n (H) = m (H) / M (H) = 9.09 / 1 = 9.09 mol;
6) m (O) = ω (O) * m (CxHyOz) / 100% = 36.36% * 100/100% = 36.36%;
7) n (O) = m (O) / M (O) = 36.36 / 16 = 2.273 mol;
8) x: y: z = n (C): n (H): n (O) = 4.546: 9.09: 2.273 = 2: 4: 1;
9) Unknown substance – C2H4O – acetaldehyde.

Answer: Unknown substance – C2H4O – acetaldehyde. One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.