Make up the formulas of substances by mass fractions of chemical elements carbon 20.0%

| August 15, 2021 | education

Make up the formulas of substances by mass fractions of chemical elements carbon 20.0% hydrogen 6.6% oxygen 26.6% nitrogen 46.7%.

Given:
CxHyOzNi
ω (C) = 20.0%
ω (H) = 6.6%
ω (O) = 26.6%
ω (N) = 46.7%

To find:
CxHyOzNi -?

Solution:
1) Let m (CxHyOzNi) = 100 g;
2) m (C) = ω (C) * m (CxHyOzNi) / 100% = 20% * 100/100% = 20 g;
3) n (C) = m (C) / M (C) = 20/12 = 1.67 mol;
4) m (H) = ω (H) * m (CxHyOzNi) / 100% = 6.6% * 100/100% = 6.6 g;
5) n (H) = m (H) / M (H) = 6.6 / 1 = 6.6 mol;
6) m (O) = ω (O) * m (CxHyOzNi) / 100% = 26.6% * 100/100% = 26.6 g;
7) n (O) = m (O) / M (O) = 26.6 / 16 = 1.66 mol;
8) m (N) = ω (N) * m (CxHyOzNi) / 100% = 46.7% * 100/100% = 46.7 g;
9) n (N) = m (N) / M (N) = 46.7 / 14 = 3.34 mol;
10) x: y: z: i = n (C): n (H): n (O): n (N) = 1.67: 6.6: 1.66: 3.34 = 1: 4: 12;
11) Unknown substance – CH4ON2.

Answer: Unknown substance – CH4ON2.



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