Question

рассчитайте массовые доли всех элементов в силане (SiH4) какова масса 22,4 л силана при норм условиях?

Answer 1

Calculation of Mass Fractions in Silane (SiH4)

To calculate the mass fractions of all elements in silane (SiH4), we need to know the molar mass of each element and the molar mass of silane itself.

The molar mass of silicon (Si) is approximately 28.09 g/mol, and the molar mass of hydrogen (H) is approximately 1.01 g/mol.

The molar mass of silane (SiH4) can be calculated as follows:

Molar mass of SiH4 = (Molar mass of Si) + 4 * (Molar mass of H) = 28.09 g/mol + 4 * 1.01 g/mol = 32.13 g/mol

Now, let's calculate the mass fractions of each element in silane.

The mass fraction of an element is calculated by dividing the molar mass of the element by the molar mass of the compound and multiplying by 100%.

Mass fraction of Si = (Molar mass of Si / Molar mass of SiH4) * 100% = (28.09 g/mol / 32.13 g/mol) * 100% ≈ 87.4%

Mass fraction of H = (4 * Molar mass of H / Molar mass of SiH4) * 100% = (4 * 1.01 g/mol / 32.13 g/mol) * 100% ≈ 12.6%

Therefore, the mass fractions of silicon (Si) and hydrogen (H) in silane (SiH4) are approximately 87.4% and 12.6%, respectively.

Calculation of the Mass of 22.4 L of Silane at Standard Conditions

To calculate the mass of 22.4 L of silane (SiH4) at standard conditions, we need to use the ideal gas law equation:

PV = nRT

Where: P = pressure (in atm) V = volume (in liters) n = number of moles R = ideal gas constant (0.0821 L·atm/(mol·K)) T = temperature (in Kelvin)

At standard conditions, the pressure is 1 atm and the temperature is 273.15 K.

Given that the volume is 22.4 L, we can rearrange the equation to solve for the number of moles (n):

n = PV / RT

Substituting the values into the equation:

n = (1 atm * 22.4 L) / (0.0821 L·atm/(mol·K) * 273.15 K) ≈ 1.007 moles

To calculate the mass, we need to multiply the number of moles by the molar mass of silane (SiH4):

Mass = n * Molar mass of SiH4 = 1.007 moles * 32.13 g/mol ≈ 32.36 g

Therefore, the mass of 22.4 L of silane (SiH4) at standard conditions is approximately 32.36 grams.

Please note that the calculations provided are based on the given molar masses and standard conditions.