Question

What is the mass of 22.4 L of H2 at STP?

Answer 1

A. 1.01 is the right answer

Since

The formula is Pv= nRT

P=1 atm

V= 22.4 L

N= x

r= 0.0821

t = 273 k (bc it’s standard temperature)

So (1)(22.4)=(x)(0.0821)(273)

X= 1.001

Answer 2

Answer: Option (b) is the correct answer.

Explanation:

STP means standard temperature and pressure. At this condition pressure is 1 atm, volume is 22.4 L and temperature is 298 K.

Therefore, using ideal gas equation we will calculate the number of moles as follows.

                             PV = nRT

                        $1 atm \times 22.4 L = n \times 0.0832 Latm K^{-1}mol^{-1} \times 298K$

                                 n = 0.903 mol

                                    = 1 mol (approx)

Hence, it is known that molar mass of hydrogen molecule is 2 g/mol. Therefore, calculate mass of $H_{2}$ at STP as follows.

                 Number of moles = $\frac{mass}{molar mass}$

                       1 mol = $\frac{mass}{2.02 g/mol}$

                          mass = 2.02 g

Thus, we can conclude that the mass of 22.4 L of H2 at STP is 2.02 grams.