A 1.00 L sample of a gas has a mass of 1.92 g at STP. What is the molar mass (molecular weight) of the gas

Given:

Now,

Number of moles will be:

=

=

hence,

The molar mass,

=

By putting the values,

=

=

Thus the answer above is correct.

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The answer is below

Explanation:

Avogadro stated that "Equal volumes of all gases at the same temperature and pressure contain the same number of molecules". Hence at standard temperature and pressure 1 mole of a gas occupies 22.4 liters of volume.

1 mol = 22.4 liters

Given a gas with 1 L and mass of 1.92 g at STP.

number of moles = 1 L / (22.4 L / mol) = 0.0446 mol

The molar mass = mass of gas / number of moles

molar mass = 1.92 g / 0.0446 mol

molar mass = 43.008 g / mol

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2