Determine in which compound the mass fraction of hydrogen is greater: a) pentane C5H12 and benzene

| September 1, 2021 | education

Determine in which compound the mass fraction of hydrogen is greater: a) pentane C5H12 and benzene C6H6 b) ammonia NH3 and hydrogen peroxide H2O2 c) methane CH4 and hydrazine N2H4 d) ethylene C2H4 and silane SiH4

w = (M (element) / M (substance)) * 100.

a) C5H12 w (H) = (M (H) / M (C5H12)) * 100;
M (C5H12) = 5 * 12 + 12 = 72 (g / mol);
w (H) = (12/72) * 100 = 18%;

M (C6H6) = 12 * 6 + 6 = 78 (g / mol);
w (H) = (12/78) * 100 = 15%;
Answer: C5H12> C6H6.

b) M (NH3) = 14 + 3 = 17 (g / mol);
w (H) = (3/17) * 100 = 18%

M (H2O2) = 2 + 16 * 2 = 34 (g / mol);
w (H) = (2/34) * 100 = 6%;
Answer: NH3> H2O2.

c) M (CH4) = 12 + 4 = 16 (g / mol);
w (H) = (4/16) * 100 = 25%

M (N2H4) = 14 * 2 + 1 * 4 = 32 (g / mol);
w (H) = (4/32) * 100 = 13%;
Answer: CH4> N2H4.

d) M (C2H4) = 12 * 2 + 4 = 28 (g / mol);
w (H) = (4/28) * 100 = 14%

M (SiH4) = 29 + 1 * 4 = 33 (g / mol);
w (H) = (4/33) * 100 = 12%;
Answer: C2H4> SiH4.



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