Why are there only two elements in the first row of the periodic table?
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Answer:
The formula of hydrocarbon =
Explanation:
% of C = 85.7
Molar mass of C = 12.0107 g/mol
% moles of C = 85.7 / 12.0107 = 7.14
% of H = 14.3
Molar mass of H = 1.00784 g/mol
% moles of H = 14.3 / 1.00784 = 14.19
Taking the simplest ratio for C and H as:
7.14 : 14.19 = 1 : 2
The empirical formula is =
Also, Given that:
Pressure = 508 Torr
Temperature = 17 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T = (17 + 273.15) K = 290.15 K
Volume = 1.500 L
Using ideal gas equation as:
where,
P is the pressure
V is the volume
n is the number of moles
T is the temperature
R is Gas constant having value = 62.3637 L.torr/K.mol
Applying the equation as:
508 Torr × 1.500 L = n × 62.3637 L.torr/K.mol × 290.15 K
⇒n = 0.0421 moles
Given that :
Amount = 1.77 g
Molar mass = ?
The formula for the calculation of moles is shown below:
Thus,
Molar mass of the hydrocarbon = 42.04 g/mol
Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.
Thus,
Molecular mass = n × Empirical mass
Where, n is any positive number from 1, 2, 3...
Mass from the Empirical formula = 1×12 + 2×1= 14 g/mol
Molar mass = 42.04 g/mol
So,
Molecular mass = n × Empirical mass
42.04 = n × 14
⇒ n = 3
<u>The formula of hydrocarbon = </u>